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Texas Instruments bq27500 User's Manual

1. 0 125 0 125 V CONV Conversion time Single conversion 1 S Resolution 14 15 bits TN Input Before 1 mV After calibration 10 uV INL Integral nonlinearity error 0 007 40 034 FSR 258 IN Effective input resistance 2 5 MQ leg 1 Input leakage current 0 3 UA 1 Specified by design Not tested in production 3 8 ADC TEMPERATURE AND CELL MEASUREMENT CHARACTERISTICS 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at T4 25 C and Voc 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS UNIT IN Input voltage range 0 2 1 V Submit Documentation Feedback ELECTRICAL SPECIFICATIONS 5 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 ADC TEMPERATURE AND CELL MEASUREMENT CHARACTERISTICS continued Ta 40 C to 85 2 4 V lt Voc lt 2 6 V Typical Values at 25 and Vec 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS MAX UNIT tADC CONV Conversion time 125 ms Resolution 14 15 bits VADC OS Input offset 1 mV ZADC1 Effective input resistance TS RID 8 0927501 only uu bq27500 1 not measuring cell voltage 8 ZADC2 Effective input resistance BAT bq27500 1 measuging cell voltage 100 Input Leakage Current 0 3 UA 1 Specified by design Not
2. ta sTa 5 t 1 tsu DAT REPEATED START START UDG 04122 Figure 3 1 I C Compatible Interface Timing Diagrams Submit Documentation Feedback ELECTRICAL SPECIFICATIONS 7 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 4 GENERAL DESCRIPTION 8 The bq27500 1 accurately predicts the battery capacity and other operational characteristics of a single Li based rechargeable cell It can be interrogated by a system processor to provide cell information such as State of Charge SOC Time to Empty TTE and Time to Full TTF Information is accessed through a series of commands called Standard Commands Further capabilities are provided by the additional Extended Commands set Both sets of commands indicated by the general format Command are used to read and write information contained within the bq27500 1 control and status registers as well as its data flash locations Commands are sent from system to gauge using the bq27500 1 s serial communications engine and can be executed during application development pack manufacture or end equipment operation Cell information is stored in the bq27500 1 in non volatile flash memory Many of these data flash locations are accessible during application development They cannot be accessed directly during end equipment operation Access to these locations is achieved by either use of the b
3. SCHEMATIC GEM UE 34 9 Submit Documentation Feedback 49 5 INSTRUMENTS www ti com 2 DEVICE INFORMATION bq27500 0427501 System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 2 1 AVAILABLE OPTIONS PART NUMBER PACKAGE TA PME EMT 5 bq27500DRZR 3000 04275000827 12 pin 2 5 mm x 4 0 mm _40 to 85 C 300 bq27501DRZR 02 SON 3000 bq27501DRZT 300 1 Forthe most current package and ordering information see the Package Option Addendum at the end of this document or see the TI website at www ti com 2 Product Preview 2 2 PIN DIAGRAMS BAT LOW BI TOUT TS bq27500 2 3 TERMINAL FUNCTIONS GD LOW BAT GD SCL BI TOUT SCL SDA TS SDA bq27501 NC BAT RID SRN SRP Vas LS SRP TERMINAL PIN NO NAME NAME Vo DESCRIPTION 1 bq27500 bq27501 Battery Low output indicator Active high by default though polarity can be configured BAT DON through the BATL_POL in Operation Configuration Push pull output Battery insertion detection input Power pin for pack thermistor network Thermistor 2 ah VBITOUT is multiplexer control pin Open drain I O use with pull up resistor gt 1 1 8MQ typical 3 TS TS P Pack thermistor voltage sense use 103AT type thermistor ADC input 4 BAT BAT l Cell voltage meas
4. SEALED Access This byte contains the checksum for the 32 bytes of block data written to Manufacturer Info Block A B or C The least significant byte of the sum of the data bytes written must be complemented 255 x for x the least significant byte before being written to 0x60 4 1 2 6 BlockDataControl 0x61 UNSEALED Access This command is used to control data flash access mode Writing 0 00 to this command enables BlockData to access general data flash Writing a 0x01 to this command enables SEALED mode operation of DataFlashBlock SEALED Access This command is not available in SEALED mode Submit Documentation Feedback GENERAL DESCRIPTION 15 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS www ti com SLUS785 SEPTEMBER 2007 4 1 2 7 DeviceNameLength 0x62 UNSEALED and SEALED Access This byte contains the length of the Device Name 4 1 2 8 DeviceName 0x63 0x69 UNSEALED and SEALED Access This block contains the device name that is programmed in Device Name 4 1 2 9 ApplicationStatus This byte function allows the system to read the Application Status register of the bq27500 01 See Section 6 1 3 for specific bit definitions 4 1 2 10 Reserved 0x6b 0x7f 4 2 DATA FLASH INTERFACE 4 2 1 ACCESSING THE DATA FLASH The bq27500 1 data flash is a non volatile memory that contains bq27500 1 initialization default cell status calibration config
5. constant current mode RUP DIS Status bit indicating the bq27500 1 Ra table updates are disabled Updates disabled when set VOK Status bit indicating the bq27500 1 voltages are OK for QMAX True when set QEN Status bit indicating the bq27500 1 QMAX updates enabled True when set 4 1 1 1 2 DEVICE TYPE 0x0001 Instructs the fuel gauge to return the device type to addresses 0x00 0x01 10 GENERAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 4 1 1 1 3 FW VERSION 0x0002 Instructs the fuel gauge to return the firmware version to addresses 0x00 0x01 4 1 1 1 4 HW VERSION 0x0003 Instructs the fuel gauge to return the hardware version to addresses 0 00 0 01 4 1 1 1 5 RESET DATA 0x0005 Instructs the fuel gauge to return the reset data to addresses 0x00 0x01 with the low byte being the number of partial resets and the high byte the number of full resets 4 1 1 1 6 PREV 0x0007 Instructs the fuel gauge to return the previous command written to addresses 0 00 0 01 4 1 1 1 7 CHEM ID 0x0008 Instructs the fuel gauge to return the chemical identifier for the Impedance Track configuration to addresses 0x00 0x01 4 1 1 1 8 BOARD OFFSET 0x0009 Instructs the fuel gauge to compute the coulomb counter offset with internal short and then without internal short applied across the SR inputs During this
6. 48 Data 6 Initial Standby Current n 256 0 10 Configuration 48 Data 7 Initial Max Load Current 12 32767 0 1000 Configuration 48 Data 9 CC Threshold 12 100 32767 1400 mAh Configuration 48 Data 12 Design Capacity 12 0 65535 1500 mAh bq27500 Configuration 48 Data 39 Device Name S8 X bq27501 Configuration 49 Discharge 0 SOCF Set 96 n 1 100 6 Configuration 49 Discharge 2 SOCF Clear 96 n 1 100 8 Configuration 49 Discharge 4 Max Load RSOC 11 0 100 50 System Data 58 ne 0 31 Block A 0 31 Hi 0x00 0x00 System Data 58 Manufacturer 32 63 Block B 0 31 0x00 0x00 5 System Data 58 5 64 95 Block C 0 31 0x00 0 00 5 18 GENERAL DESCRIPTION Submit Documentation Feedback 0427500 TEXAS 0427501 NSTRUMENTS System Side Impedance Track Fuel Gauge www ti com SLUS785 SEPTEMBER 2007 Table 4 7 Data Flash Summary continued Subclass Data Min Max Default i Class ID Subclass Offset Name Type Value Value Value Units Configuration 64 Registers 0 Operation Configuration H2 0x0000 Oxffff 0x0979 Configuration 64 Registers 2 Pack 0 Voltage U2 0 4200 1000 Configuration 64 Registers 4 Pack 1 Voltage U2 0 4200 4000 mV Configuration 64 Registers 8 Pack V Range U1 0 100 5 Configuration 68 Pow
7. A Acknowledge No Acknowledge and P Stop Figure 7 1 Supported Formats The quick read returns data at the address indicated by the address pointer The address pointer a register internal to the communication engine increments whenever data is acknowledged by the 427500 or the master Quick writes function the same manner and are a convenient means of sending multiple bytes to consecutive command locations such as two byte commands that require two bytes of data Attempt to write a read only address NACK after data sent by master p ADDR 6 0 CMD 7 0 0 AN pP Attempt to read an address above 0x7F command I Isl ADDR 6 0 CMD 7 0 Attempt at incremental writes NACK all extra data bytes sent sj paure fn An r Incremental read at the maximum allowed read address sij jA Srf 01 11 parare Address Data from Data from Ox7F addr Ox7F addr 0x00 The 2 engine releases both SDA and SCL if the bus is held low for If the fuel gauge was holding the lines releasing them frees the master to drive the lines If an external condition is holding either of the lines low the IC engi
8. LAND PATTERN DRZ 5 10x0 4 12 0 4 000000 00001 NOTES A B This C Pub D Pac for PDSO N12 Example Stencil Design Example Board Layout 0 125 thick stencil Note E 5 25 1 4 0 525 4 0 8 4x1 0 FIEL 000 12x0 8 ij 12x02 68 solder coverage on center pad Non Solder Mask Defined Pad Center Pad Geometry Example Solder Mask Opening Note F Pad Geometry Note C 4208113 A 07 06 inear dimensions are in millimeters drawing is subject to change without notice ication IPC 7351 is recommended for alternate designs This package is designed to be soldered to a thermal pad on the board Refer to Application Note Quad Flat Pack ages Texas Instruments Literature No SCBAO17 SLUA271 and also the Product Data Sheets specific thermal information via requirements and recommended board layout These documents are available at www ti com http www ti com gt E Laser cutting apertures with trapezoidal walls and also rounding corners will offer better paste release Customers should con F Cus act their board assembly site for stencil design recommendations Refer to IPC 7525 for stencil design considerations omers should contact their board fabrication site for minimum solder mask web tolerances between signal pads 8 Texas INSTRUMENTS www ti com IMPORTANT NOTICE Texas Instruments Incorporat
9. Sensitivity Level rating according to the JEDEC industry standard classifications and peak solder temperature Important Information and Disclaimer The information provided on this page represents TI s knowledge and belief as of the date that it is provided TI bases its knowledge and belief on information provided by third parties and makes no representation or warranty as to the accuracy of such information Efforts are underway to better integrate information from third parties has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals and TI suppliers consider certain information to be proprietary and thus CAS numbers and other limited information may not be available for release In no event shall TI s liability arising out of such information exceed the total purchase price of the TI part s at issue in this document sold by to Customer on an annual basis Addendum Page 1 MECHANICAL DATA DRZ S PDSO N12 PLASTIC SMALL OUTLINE PIN 1 INDEX AREA 0 20 REF Y SEATING PLANE tq EXPOSED THERMAL PAD NOTES A All linear dimensions are in millimeters 4207806 B 04 06 Dimensioning and tolerancing per ASME Y14 5M 1994 B This drawing is
10. The bq27500 1 uses temperature to monitor the battery pack environment which is used for fuel gauging and cell protection functionality To minimize power consumption the bq27500 1 has several power modes NORMAL SLEEP HIBERNATE and BAT INSERT CHECK The bq27500 1 passes automatically between these modes depending upon the occurrence of specific events though a system processor can initiate some of these modes directly More details can be found in the Section 5 7 POWER MODES NOTE FORMATTING CONVENTIONS IN THIS DOCUMENT Commands italics with parentheses and no breaking spaces e g RemainingCapacity Data Flash italics bold and breaking spaces e g Design Capacity Register Bits and Flags brackets only e g TDA Data Flash Bits italics and bold e g LED1 Modes and states ALL CAPITALS e g UNSEALED mode GENERAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas bq27501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 4 1 DATA COMMANDS 4 1 11 STANDARD DATA COMMANDS The bq27500 1 uses a series of 2 byte standard commands to enable system reading and writing of battery information Each standard command has an associated command code pair as indicated in Table 4 1 Because each command consists of two bytes of data two consecutive 2 transmissions must be executed both to initiate the command function and to read or write the corresponding two bytes of data Additi
11. Yes Forces DF Pack Configuration HIBERNATE to 0 SEALED 0x0020 No Places the bq27500 1 in SEALED access mode IT ENABLE 0x0021 No Enables the Impedance Track algorithm IFCHECKSUM 0x0022 No Reports the instruction flash checksum CALMODE 0x0040 No Places the bq27500 1 in calibration mode RESET 0x0041 No Forces a full reset of the bq27500 1 4 1 1 1 1 CONTROL STATUS 0 0000 Instructs the gas gauge to return status information to Control addresses 0x00 0x01 The status word includes the following information Table 4 3 CONTROL STATUS Bit Definitions Flags bit7 bit6 bit5 bit4 bit3 bit2 bito High Byte 5 55 Low Byte x HIBERNATE SLEEP LDMD RUP DIS VOK QEN FAS Status bit indicating the bq27500 1 is in FULL ACCESS SEALED state Active when set SS Status bit indicating the bq27500 1 is in SEALED State Active when set CCA Status bit indicating the bq27500 1 is Coulomb Counter Calibration routine is active Active when set BCA Status bit indicating the bq27500 1 Board Calibration routine is active Active when set HIBERNATE Status bit indicating a request for entry into HIBERNATE from SLEEP mode True when set Default is 0 SLEEP Status bit indicating the bq27500 1 is in SLEEP mode True when set Default is 0 LDMD Status bit indicating the bq27500 1 Impedance Track algorithm is using constant power mode True when set Default is 0
12. default minimum and maximum values Table 4 7 Data Flash Summary Subclass Data Min Max Default j Class ID Subclass Offset Name Type Value Value Value Units Configuration 2 Safety 0 OT Chg 12 0 1200 550 0 1 C Configuration 2 Safety 2 OT Chg Time U1 0 60 2 5 Configuration 2 Safety 3 OT Chg Recovery 12 0 1200 500 0 1 C Configuration 2 Safety 5 OT Dsg 12 0 1200 600 0 1 C Configuration 2 Safety 7 OT Dsg Time U1 0 60 2 5 Configuration 2 Safety 8 OT Dsg Recovery 12 0 1200 550 0 16 Configuration 32 0 Charge Inhibit Temp Low 12 400 1200 0 0 1 C Configuration 32 um 2 Charge Inhibit Temp High 12 400 1200 450 0 1 C Configuration 32 Charge Inhibit 4 Temp Hys 12 0 100 50 0 1 C Config Configuration 34 Charge 2 Charging Voltage 12 0 20000 4200 Configuration 34 Charge 4 Delta Temperature l2 0 500 50 0 19 Configuration 34 Charge 6 Suspend Temperature Low 12 400 1200 50 0 1 C Configuration 34 Charge 8 Suspend Temperature High 12 400 1200 550 0 1 C Configuration 36 Termination 2 Taper Current 12 0 1000 100 Charge n Configuration 36 Termination 4 Minimum Taper Charge 12 0 1000 64 mAh 2 Configuration 36 Termination 6 Taper Voltage 12 0 1000 100 mV Charge Configuration 36 Termination 8 Current Taper Window U1 0 60 40 S Configuration 48 Data 0 SOC1 Set 12 0 700 100 mAh Configuration
13. field for each default cell profile The Impedance Track algorithm will update these values and maintain them the associated actual cell profiles Update Status 0 and Update Status 1 Bit 1 0x02 of the Update Status n registers indicates that the bq27500 1 has learned new Qmax parameters and is accurate The remaining bits are reserved Bits 1 is user configurable however it is also a status flag that can be set by the bq27500 1 Bit 1 should never be modified except when creating a golden image file as explained in the application note Preparing Optimized Default Flash Constants for specific Battery Types see SLUA334 pdf Bit 1 is updated as needed by the bq27500 1 Avg I Last Run The bq27500 logs the current averaged from the beginning to the end of each discharge cycle It stores this average current from the previous discharge cycle in this register This register should never need to be modified It is only updated by the bq27500 1 when required Avg P Last Run The bq27500 1 logs the power averaged from the beginning to the end of each discharge cycle It stores this average power from the previous discharge cycle in this register To get a correct average power reading the bq27500 1 continuously multiplies instantaneous current times Voltage to get power It then logs this data to derive the average power This register should never need to be modified It is only updated by the bq27500 1 when required Delta Voltage The bq2
14. mV 1 1 0 5 mV or 5b mV 1 1 1 10 mV or 10 mV 1 The actual resistance value vs the setting of the sense resistor is not important just the actual voltage threshold when calculating the configuration 5 8 3 FLASH UPDATES Data Flash can only be updated if Voltage gt Flash Update OK Voltage Flash programming current can cause an increase in LDO dropout The value of Flash Update OK Voltage should be selected such that the bq27500 1 Vcc voltage does not fall below its minimum of 2 4V during Flash write operations 5 9 AUTOCALIBRATION 30 The bq27500 provides an autocalibration feature that measures the voltage offset error across SRP and SRN as operating conditions change It subtracts the resulting offset error from normal sense resistor voltage for maximum measurement accuracy Auto calibration of the ADC begins on entry to SLEEP mode except if Temperature is lt 5 C or Temperature gt 45 C The fuel gauge also performs a single offset when 1 the condition of AverageCurrent lt 100mA and 2 voltage change since last offset calibration gt 256mV or temperature change since last offset calibration is greater than 80 C for gt 60s Capacity and current measurements will continue at the last measured rate during the offset calibration when these measurements cannot be performed If the battery voltage drops more than 32mV during the offset calibration the load current has likely in
15. subject to change without notice C Small Outline No Lead SON package configuration The package thermal pad must be soldered to the board for thermal and mechanical performance See the Product Data Sheet for details regarding the exposed thermal pad dimensions E This package is lead free 48 5 INSTRUMENTS www ti com X Texas THERMAL PAD MECHANICAL DATA INSTRUMENTS www ti com DRZ R PDSO N12 HERMAL INFORMATION This package incorporates an exposed thermal pad that is designed to be attached directly to an external heatsink The thermal pad must be soldered directly to the printed circuit board PCB the PCB can be used as a heatsink In addition through the use of thermal vias the thermal pad can be attached directly to a ground plane or special heatsink structure designed into the PCB This design optimizes the heat transfer from the integrated circuit IC For information on the Quad Flatpack No Lead QFN package and its advantages refer to Application Report Quad Flatpack No Lead Logic Packages Texas Instruments Literature No SCBAO17 This document is available at www ti com The exposed thermal pad dimensions for this package are shown in the following illustration 1 6 A Exposed Thermal Pad 2 45 0 10 2AN 0 20 1 7 1 95 0 10 Bottom View NOTE All linear dimensions are in millimeters Exposed Thermal Pad Dimensions 4208114 A 07 06
16. the battery reaches full charge in minutes based upon AverageCurrent The computation accounts for the taper current time extension from the linear TTF computation based on a fixed AverageCurrent rate of charge accumulation A value of 65535 indicates the battery is not being charged 4 1 1 14 StandbyCurrent 0x1a 0x1b This read only function returns a signed integer value of the measured standby current through the sense resistor The StandbyCurrent is adaptive measurement Initially it reports the standby current programmed in Initial Standby and after spending some time in standby reports the measured standby current The register value is updated every 1 second when the measured current is above the Deadband 3mA default and is less than or equal to 2 x Initial Standby The first and last values that meet this criteria are not averaged in since they may not be stable values To approximate a 1 minute time constant each new StandbyCurrent value is computed as follows StandbyCurrent new 239 256 x StandbyCurrent o p 17 256 x AverageCurrent 4 1 1 15 StandbyTimeToEmpty 0 1 0 14 This read only function returns an unsigned integer value of the predicted remaining battery life at the standby rate of discharge in minutes The computation uses Nominal Available Capacity NAC the uncompensated remaining capacity for this computation A value of 65535 indicates battery is not being discharged Su
17. 11 Update Status 1 H1 0x00 0x03 0x00 Gas Gauging 82 State 16 Avg Last Run 12 32768 32767 300 Gas Gauging 82 State 18 Avg P Last Run 12 32768 32767 1200 mAh OCVTables 83 OCVa0 Table 0 45 OCVTables 84 OCVa1Table 0 45 See Note 2 OCVTables 85 OCVb0 Table 0 64 OCVTables 86 OCVb1 Table 0 64 Default Ra Tables 87 Ra 0 18 See Note Default Ra Tables 88 Defi Ra 0 18 Rb Tables 89 RbO Table 0 18 See Note 2 Rb Tables 90 Rb1 Table 0 18 1 bq27501 only 2 Encoded battery profile information created by bqEASY software Submit Documentation Feedback GENERAL DESCRIPTION 19 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 Table 4 7 Data Flash Summary continued Class cae Subclass Offset Name Li eod pen Units Ra Tables 91 Pack0 Ra 0 18 Ra Tables 92 1 Ra 0 18 Ra Tables 93 Pack0 Rax 0 18 See Nae Ra Tables 94 Pack1 Rax 0 18 Calibration 104 Data 0 CC Gain F4 0 1 4 0 47095 Calibration 104 Data 4 CC Delta F4 29826 1193046 280932 6 Calibration 104 Data 8 CC Offset 12 32768 32767 1667 Calibration 104 Data 10 Board Offset n 128 127 0 mV Calibration 104 Data 11 Int Temp Offset l1 128 127 0 0 1 C Calibration 104 Data 12 Ext Temp Offset n 128 127 0 0 1 C Calibration 104 Data 13 Pack V Offse
18. 4 1 1 6 Flags 0x0a 0x0b This read word function returns the contents of the gas gauge status register depicting the current operating status Table 4 4 Flags Bit Definitions bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit High Byte OTC OTD CHG_INH XCHG FC CHG Low Byte CC_OFF WAIT ID BAT DET SOC1 SOCF DSG OTC Overtemperature in Charge condition is detected True when set OTD Overtemperature in Discharge condition is detected True when set CHG NH Charge Inhibit unable to begin charging temp outside the range Charge Inhibit Temp Low Charge Inhibit Temp High True when set XCHG Charge Suspend Alert temp outside the range Suspend Temp Low Suspend Temp High True when set FC Fully Charged set when Charge termination condition is met True when set CHG Fast charging allowed True when set OFF bq27500 1 performing Coulomb Counter Offset measurement True when set Good measurement taken True when set WAIT ID Waiting to identify inserted battery True when set BAT DET Battery detected True when set SOC1 State of Charge Threshold 1 8 1 Set reached True when set SOCF State of Charge Threshold Final SOCF Set reached True when set DSG Discharging detected True when set 12 GENERAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gau
19. 49 5 INSTRUMENTS www ti com 1 INTRODUCTION 1 1 FEATURES Battery Fuel Gauge for 1 Series Li lon Applications Resides on System Main Board Works with Embedded or Removable Battery Packs e Two Varieties bq27500 Uses PACK PACK and Battery Terminals bq27501 Includes Battery Pack ID Resistor RID Terminal Micro Controller Peripheral Provides Accurate Battery Fuel Gauging Internal Temperature Sensor for System Temperature Reporting Battery Low Interrupt Warning Battery Insertion Indicator Battery ID Detection 96 bytes of Non Volatile Scratch Pad FLASH Battery Fuel Gauge Based on Patented Impedance Track Technology Models the Battery Discharge Curve for Accurate Time to Empty Predictions Automatically Adjusts for Battery Aging Battery Self Discharge and Temperature Rate Inefficiencies Low Value Sense Resistor 10mO or Less lC Interface for Connection to System Micro Controller Port e 12 Pin 2 5 mm x 4 0 mm SON Package bq27500 bq27501 System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 12 APPLICATIONS e Smartphones PDAs Digital Still and Video Cameras Handheld Terminals e or Multimedia Players 1 3 DESCRIPTION The Texas Instruments bq27500 01 System Side Li lon Battery Fuel Gauge is a micro controller peripheral that provides fuel gauging for single cell Li lon battery packs The device requires little system micr
20. 7500 1 stores the maximum difference of Voltage during short load spikes and normal load so the Impedance Track algorithm can calculate remaining capacity for pulsed loads It is not recommended to change this value OCV Default Ra Rb and Ra Tables These tables contain encoded data and with the exception of the Default Ra Tables are automatically updated during device operation No user changes should be made except for reading writing the values from a pre learned pack part of the process for creating golden image files 22 FUNCTIONAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas bq27501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 5 3 DETAILED DESCRIPTION OF DEDICATED PINS 5 3 1 The Operation Configuration Register Some bq27500 1 pins are configured via the Operation Configuration data flash register as indicated in Table 5 3 This register is programmed read via the methods desribed in Section 4 2 1 Accessing the Data Flash The register is located at subclass 64 offset 0 Table 5 3 Operation Configuration Bit Definition Operation bit7 bit6 bit5 bit4 bit3 bit2 bitO Cfg High Byte RESCAP CFG1 CFGO IWAKE RSNS1 RSNSO Low Byte IDSELEN SLEEP RMFCC BATL POL BATG POL TEMPS RESCAP No load rate of compensation is applied to the reserve capacity calculation True when set Default is 0 PFC_CFG1 PFC_
21. ACTURER INFORMATION BLOCKS The bq27350 contains 96 bytes of user programmable data flash storage Manufacturer Info Block A Manufacturer Info Block B Manufacturer Info Block The method for accessing these memory locations is slightly different depending on whether the device is in UNSEALED or SEALED modes When in UNSEALED mode and when and 0x00 has been written to BlockDataControl accessing the Manufacturer Info Blocks is identical to accessing general data flash locations First a DataFlashClass command is used to set the subclass then a DataFlashBlock command sets the offset for the first data flash address within the subclass The BlockData command codes contain the referenced data flash data When writing the data flash a checksum is expected to be received by BlockDataChecksum Only when the checksum is received and verified is the data actually written to data flash As an example the data flash location for Manufacturer Info Block B is defined as having a Subclass 58 and an Offset 32 through 63 32 byte block The specification of Class System Data is not needed to address Manufacturer Info Block B but is used instead for grouping purposes when viewing data flash info in the bq27500 1 evaluation software When in SEALED mode or when 0x01 BlockDataControl does not contain 00 data flash is no longer available in the manner used in UNSEALED mode Rather than issuing subclass information a desig
22. CFGO Pin Function Code PFC mode selection PFC 0 1 or 2 selected by 0 0 0 1 or 1 0 respectively Default is PFC 1 0 1 IWAKE RSNS1 RSNSO These bits configure the current wake function ref Table 5 3 Default is 0 0 1 IDSELEN Enables cell profile selection feature True when set Default is 1 SLEEP The fuel gauge can enter sleep if operating conditions allow True when set Default is 1 RMFCC RM is updated with the value from FCC on valid charge termination True when set Default is 1 BATL_POL BAT_LOW pin is active high True when set Default is 1 BATG_POL BAT_GD pin is active low True when cleared Default is 0 TEMPS Selects external thermistor for Temperature measurements True when set Default is 1 5 3 2 Pin Function Code Descriptions The bq27500 1 has three possible pin function variations that can be selected in accordance with the circuit architecture of the end application Each variation has been assigned a Pin Function Code or PFC When the is set to 0 only the bq27500 1 measures battery temperature under discharge and relaxation conditions The charger does not receive any information from the bq27500 1 about the temperature readings and therefore operates open loop with respect to battery temperature A of 1 is like a of 0 except temperature is also monitored during battery charging If charging temperature falls outside of the preset range defined in data flash a char
23. PARAMETER TEST CONDITIONS MIN UNIT fosc Operating frequency 2 097 MHz Ta 0 C to 60 C 2 0 0 38 2 0 feio Frequency error 7 9 20 C to 70 C 3 0 0 3896 3 0 Ta 40 C to 85 4 5 0 38 4 5 tsxo Start up time 9 2 5 5 ms 1 The frequency error is measured from 2 097 MHz 2 The frequency drift is included and measured from the trimmed frequency at Voc 2 5V Ta 25 C 3 The startup time is defined as the time it takes for the oscillator output frequency to be 3 3 6 LOW FREQUENCY OSCILLATOR 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at 25 C and Vec 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP UNIT flosc Operating frequency 32 768 kHz Ta 0 C to 60 C 1 5 0 25 1 5 Frequency error 0 2 TA 20 C to 70 C 2 5 0 25 2 5 Ta 40 C to 85 C 4 0 0 25 4 0 ti exo Start up time 9 500 us 1 The frequency drift is included and measured from the trimmed frequency at Voc 2 5V Ta 25 C 2 The frequency error is measured from 32 768 kHz 8 The startup time is defined as the time it takes for the oscillator output frequency to be 396 3 7 INTEGRATING ADC COULOMB COUNTER CHARACTERISTICS Ta 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at 25 C and Vec 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS UNIT IN Input voltage range and
24. R R Submit Documentation Feedback GENERAL DESCRIPTION 9 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 4 1 1 1 Control 0x00 0x01 Issuing Control command requires a subsequent two byte sub command These additional bytes specify the particular control function desired The Control command allows the system to control specific features of the 0427500 during normal operation and additional features when the bq27500 1 is in different access modes as described in Table 4 2 Table 4 2 Control Subcommands CNTL FUNCTION DESCRIPTION CONTROL STATUS 0x0000 Yes Reports the status of DF Checksum Hibernate IT etc DEVICE TYPE 0x0001 Yes Reports the device type eg bq27500 FW VERSION 0x0002 Yes Reports the firmware version on the device type HW VERSION 0x0003 Yes Reports the hardware version of the device type Reserved 0x0004 No Not to be used RESET DATA 0x0005 No Returns reset data Reserved 0x0006 No Not to be used PREV MACWRITE 0x0007 No Returns previous MAC command code CHEMID 0x0008 Yes 2 identifier of the Impedance BOARD OFFSET 0x0009 No Forces the device Board Offset to be measured and stored CC INT OFFSET 0x000b No Forces the device to measure and store the internal CC offset SET HIBERNATE 0x0011 Yes Forces DF Pack Configuration HIBERNATE to 1 CLEAR HIBERNATE 0x0012
25. SH MEMORY CHARACTERISTICS 3 10 INTERFACE COMMUNICATION 4 GENERAL DESCRIPTION 4 1 TIMING CHARACTERISTICS DATA COMMANDS Contents Contents 1 42 DATA FLASH INTERFACE 16 1 4 3 MANUFACTURER INFORMATION BLOCKS 17 1 44 ACCESS 12 45 SEALING UNSEALING DATA FLASH 17 3 46 DATA FLASH 5 18 3 5 FUNCTIONAL DESCRIPTION 20 3 5 1 FUEL 20 3 5 2 IMPEDANCE TRACK VARIABLES 21 4 53 DETAILED DESCRIPTION OF DEDICATED PINS 23 4 54 TEMPERATURE 26 4 55 OVERTEMPERATURE INDICATION 26 4 5 6 CHARGING AND CHARGE TERMINATION INDICATION 26 5 57 POWER 27 5 58 29 5 59 80 6 APPLICATION SPECIFIC INFORMATION 31 5 6 1 BATTERY PROFILE STORAGE AND SELECTION 31 6 2 APPLICATION SPECIFIC FLOW AND CONTROL 31 7 5 33 5 71 12 33 6 8 REFERENCE 5 34 8 84
26. Temperature falls to OT Dsg Recovery the OTD bit of Flags is reset 5 6 CHARGING AND CHARGE TERMINATION INDICATION 5 6 1 Detecting Charge Termination For proper bq27500 1 operation the cell charging voltage must be specified by the user The default value for this variable is Charging Voltage 4200mV The bq27500 1 detects charge termination when 1 during 2 consecutive periods of Current Taper Window the AverageCurrent is Taper Current and 2 during the same periods the accumulated change in capacity 0 25mAh Current Taper Window and 3 Voltage Charging Voltage Taper Voltage When this occurs the CHG bit of Flags is cleared Also if the RMFCC bit of Operation Configuration is set and HemainingCapacity is set equal to FullChargeCapacity 5 6 2 Charge Inhibit 26 When PFC 1 the bq27500 1 can indicate when battery temperature has fallen below or risen above predefined thresholds Charge Inhibit Temp Low and Charge Inhibit Temp High respectively In this mode the line is made high to indicate this condition and is returned to its ow state once battery temperature returns to the range Charge Inhibit Temp Low Temp Hys Charge Inhibit Temp High Temp Hys When 0 or 2 the bq27500 1 must be queried by the system in order to determine the battery temperature At that time the bq27500 1 will sample the temperature This saves battery energy when operating from batter
27. UNIT Voc Supply voltage range 0 3 to 2 75 V Viop Open drain pins TOUT SDA SDL GD 0 3 to 6 V VBAT BAT input pin 0 3 to 6 Vi Input voltage range to all other pins TS SRP SRN RID bq27501 only NC 0 3 to Voc 0 3 V bq27500 only 1 kV ESD Human Body Model HMB 2 kV Tr Functional temperature range 40 to 100 C Storage temperature range 65 to 150 1 Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device These stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied Exposure to absolute maximum rated conditions for extended periods may affect device reliability 3 2 RECOMMENDED OPERATING CONDITIONS 25 C Voc 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS MIN MAX UNIT Voc Supply Voltage 2 4 2 5 2 6 V loc Normal operating mode current 95 UA Low power storage mode current 15 UA loc Hibernate operating mode current 2 VoL Output voltage low SDA LOW BI TOUT lo 0 5 mA 0 4 V VoH PP Output high voltage BAT LOW 1 mA 0 5 V Output high voltage SDA SCL BI TOUT 7 Voc 0 5 v Input voltage low SDA SCL 0 3 0 8 Input v
28. UREMENT The bq27500 1 measures battery temperature via its TS input in order to supply battery temperature status information to Impedance Track and charger control sections of the gauge Alternatively it can also measure internal temperature via its on chip temperature sensor but only if the TEMPS bit of Operation Configuration register is cleared Regardless of which sensor is used for measurement a system processor can request the current battery temperature by calling the Temperature function see Section 4 1 1 Standard Data Commands for specific information The recommended thermistor circuit uses an external 103AT type thermistor Additional circuit information for connecting this thermistor to the bq27500 1 is shown in the Section 8 Reference Schematic 5 5 OVERTEMPERATURE INDICATION 5 51 Overtemperature Charge If during charging Temperature reaches the threshold of OT Chg for a period of OT Chg Time and AverageCurrent gt Chg Current Threshold then the OTC bit of Flags is set Note if OT Chg Time 0 then feature is completely disabled When Temperature falls to OT Chg Recovery the OTC of Flags is reset 5 5 2 Overtemperature Discharge If during discharging Temperature reaches the threshold of OT Dsg for a period of OT Dsg Time and AverageCurrent lt Dsg Current Threshold then the OTD bit of Flags is set Note if Dsg Time 0 then feature is completely disabled When
29. activity CONROL STATUS is set The difference between the two measurements is the Board Offset The Board Offset is written to data flash and is also returned to addresses 0x00 0x01 The user must prevent any charge or discharge current from flowing during the process This function is only available when the fuel gauge is UNSEALED When SEALED this command will only read back the Board Offset value stored in data flash 4 1 1 1 9 CC INT OFFSET 0x000A Instructs the fuel gauge to compute the coulomb counter offset with internal short applied across the SR inputs The offset value is written to data flash and is also returned to addresses 0x00 0x01 This function is only available when the fuel gauge is UNSEALED When SEALED this command will only read back the CC INT OFFSET value stored in data flash 4 1 1 1 10 SET HIBERNATE 0x0011 Instructs the fuel gauge to force the CONTROL STATUS HIBERNATE bit to 1 This will allow the gauge to enter the HIBERNATE power mode after the transition to SLEEP power state is detected The HIBERNATE bit is automatically cleared upon exiting from HIBERNATE mode 4 1 1 1 11 CLEAR HIBERNATE 0x0012 Instructs the fuel gauge to force the CONTROL STATUS HIBERNATE bit to 0 This will prevent the gauge from entering the HIBERNATE power mode after the transition to SLEEP power state is detected It can also be used to force the gauge out of HIBERNATE mode 4 1 1 1 12 SEALED 0x0020 Instructs the f
30. and regulatory ramifications of their applications and acknowledge and agree that they are solely responsible for all legal regulatory and safety related requirements concerning their products and any use of TI products in such safety critical applications notwithstanding any applications related information or support that may be provided by Further Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in such safety critical applications TI products are neither designed nor intended for use in military aerospace applications or environments unless the TI products are specifically designated by TI as military grade or enhanced plastic Only products designated by TI as military grade meet military specifications Buyers acknowledge and agree that any such use of TI products which TI has not designated as military grade is solely at the Buyer s risk and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use TI products are neither designed nor intended for use in automotive applications or environments unless the specific products are designated by TI as compliant with ISO TS 16949 requirements Buyers acknowledge and agree that if they use any non designated products in automotive applications TI will not be responsible for any failure to meet such requirements Following are URLs where you can obtain information
31. apacity 5 or a C 5 rate in mA AtRate mA Use whatever current is AtRate User Rate mA Use the value in User This gives a completely user configurable method AJOJN If ILoad Mode 1 Constant Power then the following options shown in Table 5 2 are available Table 5 2 Constant Power Model Used When Load Mode 1 LoadSelect Value Power Model Used Average discharge power from previous cycle There is an internal register that records the average discharge power through each entire discharge cycle The previous average is stored in this register Present average discharge power This is the average discharge power from the beginning of this discharge cycle until present time Average CurrentxVoltage based off the AverageCurrent and Voltage Current xVoltage based off of a low pass filtered version of AverageCurrent 145 and Voltage Design Energy 5 C Rate based off of Design Energy 5 or a C 5 rate in mA AtRate 10 mW Use whatever value is in AtRate User Rate 10mW Use the value in User Rate mW This gives a completely user configurable method 1 default nm Reserve Reserve Cap mAh determines how much actual remaining capacity exists after reaching 0 RemainingCapacity before Terminate Voltage is reached A no load rate of compensation is applied to this reserve Reserve Cap mW
32. ation SLEEP 1 and AverageCurrent is below the programmable level Sleep Current Once entry into SLEEP mode has been qualified but prior to entering it the bq27500 1 performs an ADC autocalibration to minimize offset During SLEEP mode the bq27500 1 periodically takes data measurements and updates its data set However a majority of its time is spent in an idle condition The bq27500 1 exits SLEEP if any entry condition is broken specifically when 1 AverageCurrent rises above Sleep Current or 2 a current in excess of lwaxe through Rsense is detected In the event that a battery is removed from the system while a charger is present and powering the gauge Impedance Track updates are not necessary Hence the fuel gauge enters a state that checks for battery insertion and does not continue executing the Impedance Track M algorithm 5 7 3 BAT INSERT CHECK MODE This mode is a halted CPU state that occurs when an adapter or other power source is present to power the bq27500 1 and system yet no battery has been detected When battery insertion is detected a series of initialization activities begin which include OCV measurement setting the BAT_GD pin and selecting the appropriate battery profiles Some commands issued by a system processor be processed while the bq27500 1 is halted in this mode The gauge will wake up to process the command then return to the halted state awaiting battery insertion Submi
33. attery is not being discharged The value is reported in units of mW 4 1 1 20 TimeToEmptyAtConstantPower 0x26 0x27 This read only function returns an unsigned integer value of the predicted remaining operating time if the battery is discharged at the AveragePower value in minutes A value of 65535 indicates AveragePower 0 The fuel gauge automatically updates TimeToEmptyatContantPower based on the AveragePower value every 1s 4 1 1 21 CycleCount 0x2a 0x2b This read only function returns an unsigned integer value of the number of cycles the battery has experienced with a range of 0 to 65535 One cycle occurs when accumulated discharge CC Threshold 4 1 1 22 StateOfCharge 0 2 0 2 This read only function returns an unsigned integer value of the predicted remaining battery capacity expressed as a percentage of FullChargeCapacity with a range of 0 to 100 4 1 2 EXTENDED DATA COMMANDS Extended commands offer additional functionality beyond the standard set of commands They are used in the same manner however unlike standard commands extended commands are not limited to 2 byte words The number of commands bytes for a given extended command ranges in size from single to multiple bytes as specified in Table 4 5 For details on the SEALED and UNSEALED states see Section 4 4 Access Modes Table 4 5 Extended Data Commands NAME cope UNTS Accessi Reserv
34. bmit Documentation Feedback GENERAL DESCRIPTION 13 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 4 1 1 16 MaxLoadCurrent 0x1e 0x1f This read only function returns a signed integer value in units of mA of the maximum load conditions The MaxLoadCurrent is an adaptive measurement which is initially reported as the maximum load current programmed in Initial Max Load Current If the measured current is ever greater than Initial Load Current then MaxLoadCurrent updates to the new current MaxLoadCurrent is reduced to the average of the previous value and Initial Max Load Current whenever the battery is charged to full after a previous discharge to an SOC less than 5096 This prevents the reported value from maintaining an unusually high value 4 1 1 17 MaxLoadTimeToEmpty 0x20 0x21 This read only function returns an unsigned integer value of the predicted remaining battery life at the maximum load current discharge rate in minutes A value of 65535 indicates that the battery is not being discharged 4 1 1 18 AvailableEnergy 0x22 0x23 This read only function returns an unsigned integer value of the predicted charge or energy remaining in the battery The value is reported in units of mWh 4 1 1 19 AveragePower 0x24 0x25 This read word function returns an unsigned integer value of the average power of the current discharge A value of 0 indicates that the b
35. creased considerably hence the offset calibration will be aborted FUNCTIONAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 6 APPLICATION SPECIFIC INFORMATION 6 1 BATTERY PROFILE STORAGE AND SELECTION 6 1 1 General Profile Description When a battery pack is removed from system equipment that implements the bq27500 01 the fuel gauge will maintain some of the battery s information in case it is re inserted This way the Impedance Track algorithm has a means of recovering battery status information thereby maintaining good State of Charge SOC estimates Two default battery profiles are available to store battery information They are used to provide the Impedance Track algorithm with the default information on two possible battery types expected to be used with the end equipment These default profiles can be used to support batteries of different chemistry same chemistry but different capacities or same chemistry but different models Default profiles are programmed by the end equipment manufacturer Note that in the case of bq27500 only one of the default profiles can be selected and this selection cannot be changed during end equipment operation In addition to the default profiles the bq27500 01 maintains two abbreviated profiles These tables hold dynamic battery data and keep track of the status for up to two of t
36. ction to support existing customers but TI does not recommend using this part in a new design PREVIEW Device has been announced but is not in production Samples may or may not be available OBSOLETE TI has discontinued the production of the device 2 Eco Plan The planned eco friendly classification Pb Free ROHS Pb Free RoHS Exempt or Green RoHS 8 no Sb Br please check http Avww ti com productcontent for the latest availability information and additional product content details TBD The Pb Free Green conversion plan has not been defined Pb Free RoHS TI s terms Lead Free or Pb Free mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances including the requirement that lead not exceed 0 196 by weight in homogeneous materials Where designed to be soldered at high temperatures TI Pb Free products are suitable for use in specified lead free processes Pb Free RoHS Exempt This component has a RoHS exemption for either 1 lead based flip chip solder bumps used between the die and package or 2 lead based die adhesive used between the die and leadframe The component is otherwise considered Pb Free RoHS compatible as defined above Green RoHS amp no Sb Br TI defines Green to mean Pb Free RoHS compatible and free of Bromine Br and Antimony Sb based flame retardants Br or Sb do not exceed 0 196 by weight in homogeneous material 3 MSL Peak Temp The Moisture
37. d the Qmax value to determine FullChargeCapacity and StateOfCharge specifically for the present load and temperature FullChargeCapacity is reported as capacity available from a fully charged battery under the present load and temperature until Voltage reaches the Term Voltage NominalAvailableCapacity and FullAvailableCapacity are the uncompensated no or light load versions of RemainingCapacity and FullChargeCapacity respectively The bq27500 1 has two flags accessed by the F ags function that warns when the cell s SOC has fallen to critical levels When RemainingCapacity falls below the first capacity threshold specified in SOC1 Set the SOC 1 State of Charge Initial flag is set The flag is cleared once RemainingCapacity rises above 5 Set All units are in mAh When RemainingCapacity falls below the second capacity threshold SOCF Set the SOCF State of Charge Final flag is set serving as a final discharge warning If SOCF Set 1 the flag is inoperative during discharge Similarly when HemainingCapacity rises above SOCF Clear and the SOCF flag has already been set the SOCF flag will be cleared provided SOCF Set 1 All units are in mAh FUNCTIONAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas bq27501 INSTRUMENTS System Side Impedance Track Fuel Gauge www ti com SLUS785 SEPTEMBER 2007 5 2 IMPEDANCE TRACK VARIABLES The bq27500 1 has
38. eak 1 8 pull up resistor will keep the pin high while no battery is present When a battery is inserted or is already inserted into the system device the BI TOUT pin will be pulled low This state is detected by the fuel gauge which polls this pin every second when the gauge has power A battery disconnected status is assumed when the bq27500 1 reads a thermistor voltage that is near 2 5V FUNCTIONAL DESCRIPTION Submit Documentation Feedback 49 5 INSTRUMENTS www ti com bq27500 0427501 System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 Start Bq27500 POR Batt No detected wes Init disabled OCV 4 taken BAT_GD enabled Y Battery Volt No Sufficient to FG Yes Batt Present IT Operations dsg chg rlx Icc gt Istandby T gt 30min Bad batt detected Batt removed Batt N removed No Batt Present OR bad batt BAT GD disabled Forced SLEEP Mode Batt Bad batt detected detected AC or USB Present End Figure 5 1 BAT GD Pin Operation Based Upon Battery Presence and bq27500 Operating Mode Submit Documentation Feedback FUNCTIONAL DESCRIPTION 25 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 5 4 TEMPERATURE MEAS
39. ection If the bq27501 measures a voltage other than Pack 0 Voltage or Pack 1 Voltage then it sets the Application Configuration UNSUPBAT to 1 alerting the system that the inserted battery is not supported The system can use this information to download the default profile for this battery if one exists The system should unseal the gauge then download the new battery profile into the older Defn Ra memory profile The last used profile is indicated by the Application Configuration LU PROF bit Overwriting the older default profile allows the bq27501 to retain information stored regarding the most recently used battery After the new default profile is downloaded the bq27501 clears the Application Configuration UNSUPBAT When the bq27501 starts operation for the first time it copies the Def0 Ra profile into the 0 Ra profile and the Ra profile into the Pack Ra profile Then when a battery pack is inserted for the first time the bq27501 starts gauging using Ha profile if the voltage measured on the RID pin is Pack 0 Voltage or starts gauging using Pack Ra profile if the voltage measured on the RID pin is Pack 1 Voltage The Impedance Track algorithm regularly updates the specific Packn Ra profile as the battery is used If a pack is replaced with a second pack having the same resistor ID as the first cell impedance is measured after pack detection as explained in Section 6 1 2 1 First OCV and Impedance Measu
40. ed RSVD 0x34 0x3b N A R R DesignCapacity DCAP 0 3 Ox3d mAh R R DataFlashClass 9 DFCLS Ox3e N A N A R W DataFlashBlock DFBLK Ox3f N A R W R W Authenticate BlockData A DF 0 40 0 53 R W R W AuthenticateCheckSum BlockData ACKS DFD 0x54 N A R W R W 1 SEALED and UNSEALED states are entered via commands to CNTL 0x00 0x01 2 In sealed mode data flash CANNOT be accessed through commands 0x3e and Ox3f 14 GENERAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gauge www ti com SLUS785 SEPTEMBER 2007 Table 4 5 Extended Data Commands continued NAME cope UNITS access accEssine BlockData DFD 0 55 0 5 R R W BlockDataCheckSum DFDCKS 0x60 N A R W R W BlockDataControl DFDCNTL 0x61 N A N A R W DeviceNameLength DNAMELEN 0x62 N A R R DeviceName DNAME 0x63 0x69 N A R R ApplicationStatus APPSTAT 0x6a N A R R Reserved RSVD Ox6b 0x7f N A R R 4 1 2 1 DesignCapacity 0x3c 0x3d SEALED and UNSEALED Access This command returns the theoretical or nominal capacity of a new pack The value is stored in Design Capacity and is expressed in mAh This is intended to be the theoretical or nominal capacity of a new pack but has no bearing on the operation of the fuel gauge functionality 4 1 2 2 DataFlashClass 0 3 UNSEALED Access This com
41. ed and its subsidiaries TI reserve the right to make corrections modifications enhancements improvements and other changes to its products and services at any time and to discontinue any product or service without notice Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete All products are sold subject to Tl s terms and conditions of sale supplied at the time of order acknowledgment TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with 5 standard warranty Testing and other quality control techniques are used to the extent deems necessary to support this warranty Except where mandated by government requirements testing of all parameters of each product is not necessarily performed TI assumes no liability for applications assistance or customer product design Customers are responsible for their products and applications using Tl components To minimize the risks associated with customer products and applications customers should provide adequate design and operating safeguards TI does not warrant or represent that any license either express or implied is granted under any TI patent right copyright mask work right or other TI intellectual property right relating to any combination machine or process in which TI products or services are used Information published by TI rega
42. epending on which default impedance profile most closely matches Care is taken not to over write the last used Packn profile 6 2 2 Battery With Resistor ID bq27501 Only 32 The bq27501 can administrate the information of up to two battery packs For a given pack connected to the fuel gauge the identity of the battery is determined by a combination of 1 reading the pack ID resistor and 2 measuring the impedance of the currently connected pack and 3 remembering which pack characteristics were most recently used by the gauge A battery pack s ID resistor should connect to the RID pin of the fuel gauge Either A Q or B resistor values should be used to indicate the battery type If a battery connection is detected bq27501 measures the voltage developed at RID If the voltage is Pack 0 Voltage then it is identified as battery pack with A resistor and bq27501 will use the Ra profile If the voltage measured is Pack 1 Voltage then it is identified as battery pack with resistor and the bq27501 will use Pack Ra profile The measurement window around each threshold is specified by Pack V96 Range which indicates the positive or negative deviation around each level Choosing RID values of 5000 and 8 for A and B correspond to Pack 0 Voltage and Pack 1 Voltage threshold levels of 110mV and 1070 respectively These resistance values assume a 3000 resistance already exists in front of the RID pin for ESD prot
43. er 0 Flash Update OK Voltage 12 0 4200 2800 mV Configuration 68 Power 7 Sleep Current 12 0 100 10 Configuration 68 Power 16 Bat Low Threshold 12 0 700 100 mAh Configuration 68 Power 18 Hibernate Voltage Threshold U2 2400 3000 2550 mV Gas Gauging 80 IT Cfg 0 Load Select U1 0 255 1 Gas Gauging 80 IT Cfg 1 Load Mode U1 0 255 0 Gas Gauging 80 IT Cfg 48 Terminate Voltage 12 32768 32767 3000 Gas Gauging 80 IT Cfg 53 User Rate mA 12 0 9000 0 Gas Gauging 80 IT Cfg 55 User Rate mW 12 0 14000 0 10mW Gas Gauging 80 IT Cfg 57 Reserve Cap mAh 12 0 9000 0 mAh Gas Gauging 80 IT Cfg 59 Reserve Cap mWh 12 0 14000 0 10mWh Current Gas Gauging 81 Thresholds 0 Dsg Current Threshold 12 0 2000 15 Current Gas Gauging 81 Thresholds 2 Chg Current Threshold 12 0 2000 75 Current Gas Gauging 81 Thresholds 4 Quit Current 12 0 1000 50 Current Gas Gauging 81 Thresholds 6 Dsg Relax Time U2 0 8191 1800 S Current Gas Gauging 81 Thresholds 8 Chg Relax Time U1 0 255 60 S Current 4 Gas Gauging 81 Thresholds 9 Quit Relax Time U1 0 63 1 S Gas Gauging 82 State 0 IT Enable H1 0x00 Oxff 0x00 Gas Gauging 82 State 1 Application Status H1 0x00 Oxff 0x00 Gas Gauging 82 State 2 Qmax 0 12 0 32767 1500 mAh Gas Gauging 82 State 4 Cycle Count 0 U2 0 65535 0 Gas Gauging 82 State 6 Update Status 0 H1 0x00 0x03 0x00 Gas Gauging 82 State 7 Qmax 1 12 0 32767 1500 mAh Gas Gauging 82 State 9 Cycle Count 1 U2 0 65535 0 Gas Gauging 82 State
44. ge SLUS785 SEPTEMBER 2007 4 1 1 7 NominalAvailableCapacity Ox0c OxOd This read only command pair returns the uncompensated no or light load battery capacity remaining Units are mAh per bit 4 1 1 8 FullAvailableCapacity 0 0 0 01 This read only command pair returns the uncompensated no or light load capacity of the battery when fully charged Units are mAh per bit FullAvailableCapacity is updated at regular intervals as specified by the IT algorithm 4 1 1 9 RemainingCapacity 0x10 0x11 This read only command pair returns the compensated battery capacity remaining Units are mAh per bit 4 1 1 10 FullChargeCapacity 0x12 13 This read only command pair returns the compensated capacity of the battery when fully charged Units are mAh per bit FullChargeCapacity is updated at regular intervals as specified by the IT algorithm 4 1 1 11 AverageCurrent 0x14 0x15 This read only command pair returns a signed integer value that is the average current flow through the sense resistor It is updated every 1 second Units are mA per bit 4 1 1 12 0x16 0x17 This read only function returns an unsigned integer value of the predicted remaining battery life at the present rate of discharge in minutes A value of 65535 indicates battery is not being discharged 4 1 1 13 TimeToFull 0x18 0x19 This read only function returns an unsigned integer value of predicted remaining time until
45. ger can be disabled via the BAT pin until cell temperature recovers See Section 5 6 2 Charge Inhibit for additional details Finally when the PFC is set to 2 the battery thermistor can be shared between the fuel gauge and the charger The charger has full usage of the thermistor during battery charging while the fuel gauge uses the thermistor exclusively during discharge and battery relaxation is specified in Operation Configuration PFC CFG1 CFG0 The default is PFC 1 5 3 3 BAT LOW Pin The LOW pin provides a system processor with an electrical indicator of battery status The signaling on the LOW pin follows the status of the 5 17 bit in the Flags register Note that the polarity of the BAT LOW pin can be inverted via the BATL POL bit of Operation Configuration 5 3 4 Power Path Control with the Pin The bq27500 1 must operate in conjunction with other electronics in a system appliance such as chargers and other IC s and subcircuits that draw appreciable power After a battery is inserted into the system this electronics must be disabled so that an accurate can be read The is used for helping determine which battery profile to use as it constitutes part of the battery impedance measurement When a battery is inserted into a system the Impedance Track algorithm requires that no charging of the battery takes place and that any discharge is limited to less t
46. h Reserve Cap mWh determines how much actual remaining capacity exists after reaching O AvailableEnergy before Terminate Voltage is reached A no load rate of compensation is applied to this reserve capacity Submit Documentation Feedback FUNCTIONAL DESCRIPTION 21 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS www ti com SLUS785 SEPTEMBER 2007 Dsg Current Threshold This register is used as a threshold by many functions in the bq27350 to determine if actual discharge current is flowing into or out of the cell The default for this register is 100mA which should be sufficient for most applications This threshold should be set low enough to be below any normal application load current but high enough to prevent noise or drift from affecting the measurement Chg Current Threshold This register is used as a threshold by many functions in the bq27500 1 to determine if actual charge current is flowing into or out of the cell The default for this register is 50mA which should be sufficient for most applications This threshold should be set low enough to be below any normal charge current but high enough to prevent noise or drift from affecting the measurement Quit Current Dsg Relax Time Chg Relax Time and Quit Relax Time The Quit Current is used as part of the Impedance Track algorithm to determine when the bq27500 enters relaxation mode from a current flowing mode in either the charge direction o
47. han C 20 these conditions are sufficient Submit Documentation Feedback FUNCTIONAL DESCRIPTION 23 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 www ti com for the fuel gauge to take an accurate OCV reading To disable these functions the BAT GD pin is merely set high floating output pulled high Once an reading has be made the pin is pulled ow thereby enabling battery charging and regular discharge of the battery The Operation Configuration BATG POL bit can be used to set the polarity of the battery good signal should the default configuration need to be changed The flowchart of Figure 5 1 details how the pin functions in the context of battery insertion and removal as well as NORMAL vs SLEEP modes In PFC 1 the BAT GD pin is also used to disable battery charging when the bq27500 1 reads battery temperatures outside the range defined by Charge Inhibit Temp Low Charge Inhibit Temp High The BAT GD line is returned to low once temperature falls within the range Charge Inhibit Temp Low Temp Hys Charge Inhibit Temp High Temp Hys 5 3 5 Battery Detection Using the BI TOUT Pin 24 During power up or HIBERNATE activities or any other activity where the bq27500 1 needs to determine whether a battery is connected or not the fuel gauge applies a test for battery presence First the BI TOUT pin is put into high Z status The w
48. he most recent batteries used In most cases the bq27500 01 can administrate information on two removable battery packs 6 1 2 Activities Upon Pack Insertion 6 1 2 1 First OCV and Impedance Measurement At power up the BAT GD pin is inactive so that the system cannot obtain power from the battery this depends on actual implementation In this state the battery is put in an open circuit condition Next the bq27500 1 measures its first open circuit voltage via the BAT pin From the OCV SOC table the SOC of the inserted battery is found Then the pin is made active and the impedance of the inserted battery is calculated from the measured voltage and the load current 7 5 OCV SOC V 1 This impedance is compared with the impedance of the dynamic profiles Packn Ra and default profiles Defn Ra for the same SOC the letter n depicts either a 0 or 1 6 1 2 2 Reading Application Status The Application Status data flash location contains cell profile status information and can be read using the ApplicationStatus Extended Command 0x6a 0x6b The bit configuration of this function location is shown in Section 6 1 3 Table 6 1 3 ApplicationStatus bit Definitions Application bit7 bit6 bit5 bit4 bit3 bit2 bitO Configuration Byte UNSUPBAT LU_ PROF UNSUPBAT Flag indicating inserted battery is not supported the current cel
49. l profiles True when set bq27501 only LU PROF Last profile used by gas gauge 0 last used when cleared Cell1 last used when set Default is 0 6 2 APPLICATION SPECIFIC FLOW AND CONTROL 6 2 1 Simple Battery bq27500 Only The bq27500 supports only one type of battery profile This profile is stored in both the DefO0 Ra and Ra profiles When a battery pack is inserted for the first time the default profile is copied into the Packn Ra profiles Then the Impedance Track algorithm begins gas gauging regularly updating Packn Ha as the battery is used When an existing pack is removed from the bq27500 and a different or same pack is inserted cell Submit Documentation Feedback APPLICATION SPECIFIC INFORMATION 31 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 impedance is measured immediately after battery detection The bq27500 chooses the profile which is closest to the measured impedance starting with the Packn Ha profiles That is if the measured impedance matches 0 Ha then the 0 Ra profile is used If the measured impedance matches Pack1 Ha then the Pack1 Ra profile is used If the measured impedance does not match the impedance stored in either Pack0 or Pack1 the battery pack is deemed new not any of the previously used packs Either the 0 Ra or Ra profile is copied into either the Pack0 or Pack Ha profile d
50. lf of a two function command set used to set the AtRate value used in calculations made by the AtHateTimeToEmpty function The AtRate units are in mA The AtRate value is a signed integer and both positive and negative values will be interpreted as discharge current value The AtRateTimeToEmpty function returns the predicted operating time at the AtRate value of discharge The default value for AtRate is zero and will force AtHate to return 65535 Both the AtRate and AtRateTimeToEmpty commands should only be used in NORMAL mode 4 1 1 3 AtRateTimeToEmpty 0x04 0x05 This read word function returns an unsigned integer value of the predicted remaining operating time if the battery is discharged at the AtHate value in minutes with a range of 0 to 65534 A value of 65535 indicates AtHate 0 The gas gauge updates AtHateTimeToEmpty within 1s after the system sets the AtRate value The fuel gauge automatically updates AtRateTimeToEmpty based on the AtRate value every 1s Both the AtRate AtRateTimeToEmpty commands should only be used in NORMAL mode 4 1 1 4 Temperature 0x06 0x07 This read word function returns an unsigned integer value of the temperature in units of 0 1 K measured by the gas gauge and has a range of 0 to 6553 5 K 4 1 1 5 Voltage 0x08 0x09 This read word function returns an unsigned integer value of the measured cell pack voltage in mV with a range of 0 to 6000 mV
51. mand sets the data flash class to accessed The class to be accessed should be entered in hexadecimal SEALED Access This command is not available in SEALED mode 4 1 2 3 DataFlashBlock Ox3f UNSEALED Access This command sets the data flash block to be accessed When 0x00 is written to BlockDataControl DataFlashBlock holds the block number of the data flash to be read or written Example writing a 0x00 to DataFlashBlock specifies access to the first 32 byte block and a 0x01 specifies access to the second 32 byte block and so on SEALED Access This command directs which data flash block will be accessed by the BlockData command Writing a 0x00 to DataFlashBlock specifies the BlockData command will transfer authentication data Issuing a 0x01 0 02 or 0 03 instructs the BlockData command to transfer Manufacturer Info Block A B or C respectively 4 1 2 4 BlockData 0x40 0x5f UNSEALED Access This data block is the remainder of the 32 byte data block when accessing data flash SEALED Access This data block is the remainder of the 32 byte data block when accessing Manufacturer Block Info A B or C 4 1 2 5 BlockDataChecksum 0x60 UNSEALED Access This byte contains the checksum on the 32 bytes of block data read or written to data flash The least significant byte of the sum of the data bytes written must be complemented 255 x for x the least significant byte before being written to 0x60
52. nated Manufacturer Information Block is selected with the DataFlashBlock command Issuing a 0x01 0x02 or 0x03 with this command causes the corresponding information block A B or C respectively to be transferred to the command space 0x40 0x5f for editing or reading by the system Upon successful writing of checksum information to BlockDataChecksum the modified block is returned to data flash Note Manufacturer Info Block A is read only when in SEALED mode 4 4 ACCESS MODES The bq27500 1 provides three security modes in which control data flash access permissions according to Table 4 6 Public Access refers to those data flash locations specified in Table 4 7 that are accessible to the user Private Access refers to reserved data flash locations used by the bq27500 1 system Care should be taken to avoid writing to Private data flash locations when performing block writes in FULL ACCESS mode by following the procedure outlined in Section 4 2 f Table 4 6 Data Flash Access Security Mode DF Public Access DF Private Access BOOTROM N A N A FULL ACCESS R W R W UNSEALED R W R W SEALED R N A Although FULL ACCESS and UNSEALED modes appear identical FULL ACCESS allows the bq27500 1 to directly transition to BOOTROM mode and also write access mode transition keys The UNSEAL mode lacks these abilities 4 5 SEALING UNSEALING DATA FLASH The bq27500 1 implements a key access scheme to transition be
53. nd space Finally the data residing in the command space is transferred to data flash once the correct checksum for the whole block is written to BlockDataChecksum 0x60 Occasionally a data flash CLASS will be larger than the 32 byte block size In this case the DataFlashBlock command is used to designate in which 32 byte block the desired locations resides The correct command address is then given by 0x40 offset modulo 32 For example to access Terminate Voltage in the Gas Gauging class DataFlashClass is issued 80 0x50 to set the class Because the offset is 48 it must reside in the second 32 byte block Hence DataFlashBlock is issued 0x01 to set the block offset and the offset used to index into the BlockData memory area is 0x40 48 modulo 32 0x40 16 0x40 0x10 0x50 Reading and writing subclass data are block operations up to 32 bytes in length If during a write the data length exceeds the maximum block size then the data is ignored None of the data written to memory are bounded by the bq27500 1 the values are not rejected by the fuel gauge Writing an incorrect value may result in hardware failure due to firmware program interpretation of the invalid data The written data is persistent so a Power On Reset does resolve the fault 16 GENERAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas bq27501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 4 3 MANUF
54. ne enters the low power sleep mode Submit Documentation Feedback COMMUNICATIONS 33 INSTRUMENTS www ti com 49 5 System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 8 REFERENCE SCHEMATICS 8 1 SCHEMATIC bq27500 bq27501 uonooijddo goc zbq 40 1495944 you sjueuoduJoo oss Kies SNOLLO3NNOO IYON SSA M39NVHO W3ISAS OL avoi 2 1 0Vd VAOS W3LSAS OL vas 1925 W31SAS OL 125 SNOLLO3NNOO 109 0149 WALSAS OL a5 1 8 OQ 1 3398VHO NW31SAS 1 005 254 in LAANI 0189 W31SAS OL 104 WLISIG Old9 W31SAS OL 11001 18 13 104100 001 AS Z GANIVLSNS OL SLAANI LVGA 3393VHO W3ISAS OL Submit Documentation Feedback REFERENCE SCHEMATICS 34 49 Texas PACKAGE OPTION ADDENDUM INSTRUMENTS www ti com 25 Sep 2007 PACKAGING INFORMATION Orderable Device Status Package Package Pins Package Eco Plan Lead Ball Finish MSL Peak Temp Type Drawing Qty BQ27500DRZR ACTIVE SON DRZ 12 3000 TBD Call TI Call TI BQ27500DRZT ACTIVE SON DRZ 12 250 TBD Call TI Call TI 0 The marketing status values are defined as follows ACTIVE Product device recommended for new designs LIFEBUY TI has announced that the device will be discontinued and a lifetime buy period is in effect NRND Not recommended for new designs Device is in produ
55. o controller firmware development The bq27500 01 resides on the system s main board and manages an embedded battery non removable or a removable battery pack The bq27500 01 uses the patented Impedance Track algorithm for fuel gauging and provides information such as remaining battery capacity mAh state of charge run time to empty min battery voltage mV and temperature C Battery fuel gauging with the bq27500 requires only PACK P PACK P and Thermistor T connections to a removable battery pack or embedded battery circuit The bq27501 works with identification resistors in battery packs to gauge batteries of different fundamental chemistries and or significantly different rated capacities TYPICAL APPLICATION Host System Power Management Controller Single Cell Li lon Battery Pack Voltage Sense Battery Lo us RID Warning Sense Temp Sense bq27500 1 Battery Good bq27501 Only Please be aware that an important notice concerning availability standard warranty use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this document Impedance Track is a trademark of Texas Instruments is a trademark of Philips Electronics UNLESS OTHERWISE NOTED this document contains PRODUCTION DATA information current as of publication date Products conform to
56. oltage high SDA SCL 2 CiN Input capacitance 5 pF Vat Input voltage range TS RID bq27501 only 0 125 2 V Input voltage range BAT 0 125 5 V Input voltage range SRP SRN 0 125 0 125 V tPUCD Power up communication delay 250 ms TA Operating free air temperature range 40 85 1 High level of system activity 2 Low level of system activity 3 Fuel gauge algorithm power inactive Only able to receive IC communication 3 3 POWER ON RESET 40 C to 85 C Typical Values at 25 C and Vegar 3 6 V unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Vire Positive going battery voltage input at Vcc 2 09 2 20 2 31 V Vuys 45 115 185 4 ELECTRICAL SPECIFICATIONS Submit Documentation Feedback 0427500 49 Texas bq27501 INSTRUMENTS System Side Impedance Track Fuel Gauge B SLUS785 SEPTEMBER 2007 3 4 INTERNAL TEMPERATURE SENSOR CHARACTERISTICS 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at T4 25 C and Vec 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS MIN UNIT Temperature sensor voltage gain 2 0 mV C 3 5 HIGH FREQUENCY OSCILLATOR Ta 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at 25 and Vec 2 5 V unless otherwise noted
57. on other Texas Instruments products and application solutions Products Applications Amplifiers amplifier ti com Audio www ti com audio Data Converters dataconverter ti com Automotive www ti com automotive DSP dsp ti com Broadband www ti com broadband Interface interface ti com Digital Control www ti com digitalcontrol Logic logic ti com Military www ti com military Power Mgmt power ti com Optical Networking www ti com opticalnetwork Microcontrollers microcontroller ti com Security www ti com security RFID www ti rfid com Telephony www ti com telephony Low Power www ti com lpw Video amp Imaging www ti com video Wireless Wireless www ti com wireless Mailing Address Texas Instruments Post Office Box 655303 Dallas Texas 75265 Copyright 2007 Texas Instruments Incorporated
58. onal options for transferring data such as spooling are described in Section 7 1 INTERFACE Standard commands are accessible in NORMAL operation Read Write permissions depend on the active access mode SEALED or UNSEALED for details on the SEALED and UNSEALED states see Section 4 4 Access Modes Table 4 1 Standard Commands NAME CODE UNIS ACCESS ACCESS Control CNTL 0x00 0x01 N A R W R W AtRate AR 0x02 0x03 mA R W R W AtRateTimeToEmpty ARTTE 0x04 0x05 Minutes R R Temperature TEMP 0x06 0x07 0 1 K R R Voltage VOLT 0x08 0x09 mV R R Flags FLAGS 0x0a OxOb N A R R NominalAvailableCapacity NAC 0 OxOd mAh R R FullAvailableCapacity FAC 0 0 OxOf mAh R R RemainingCapacity RM 0x10 0 11 mAh R R FullChargeCapacity FCC 0x12 0 13 mAh R R AverageCurrent 0x14 0x15 mA R R TimeToEmpty TTE 0x16 0x17 Minutes R R TimeToFull TTF 0x18 0x19 Minutes R R StandbyCurrent SI 0x1a 0 10 mA R R StandbyTimeToEmpty STTE Ox1c Oxid Minutes R R MaxLoadCurrent MLI 0 1 Ox1f mA R R MaxLoadTimeToEmpty MLTTE 0x20 0x21 Minutes R R AvailableEnergy AE 0x22 0x23 10mWhr R R AveragePower AP 0x24 0x25 10 TimeToEmptyAtConstantPower TTECP 0x26 0x27 Minutes R R Reserved RSVD 0x28 0x29 N A R R CycleCount 0x2a Ox2b Counts R R StateOfCharge SOC Ox2c Ox2d 96
59. q27500 1 s companion evaluation software through individual commands or through a sequence of data flash access commands To access a desired data flash location the correct data flash subclass and offset must be known The bq27500 provides 96 bytes of user programmable data flash memory partitioned into 32 byte blocks Manufacturer Info Block A Manufacturer Info Block B and Manufacturer Info Block C This data space is accessed through a data flash interface For specifics on accessing the data flash see Section 4 3 Manufacturer Information Blocks The key to the bq27500 1 s high accuracy gas gauging prediction is Texas Instrument s proprietary Impedance Track algorithm This algorithm uses cell measurements characteristics and properties to create state of charge predictions that can achieve less than 196 error across a wide variety of operating conditions and over the lifetime of the battery The bq27500 1 measures charge discharge activity by monitoring the voltage across a small value series sense resistor 5 mQ to 20 typ located between the system s Vss and the battery s PACK terminal When a cell is attached to the bq27500 1 cell impedance is computed based on cell current cell Open Circuit Voltage OCV and cell voltage under loading conditions bq27500 1 can use thermistor default is Semitec 103AT for temperature measurement or can also be configured to use its internal temperature sensor
60. r the discharge direction The value of Quit Current is set to a default value of 10mA and should be above the standby current of the system Either of the following criteria must be met to enter relaxation mode 1 AverageCurrent Quit Current Dsg Relax Time 2 AverageCurrent Quit Current tor Chg Relax Time After about 30 minutes in relaxation mode the bq27500 attempts to take accurate OCV readings An additional requirement of dV dt lt 4 uV sec is required for the bq27500 1 to perform Qmax updates These updates are used in the Impedance Track algorithms It is critical that the battery voltage be relaxed during OCV readings to and that the current is not be higher than C 20 when attempting to go into relaxation mode Quit Relax Time specifies the minimum time required for AverageCurrent to remain above the QuitCurrent threshold before exiting relaxation mode Qmax 0 and Qmax 1 Generically called Qmax these dynamic variables contain the respective maximum chemical capacity of the active cell profiles and are determined by comparing states of charge before and after applying the load with the amount of charge passed They also correspond to capacity at very low rate of discharge such as C 20 rate For high accuracy this value is periodically updated by the bq27500 1 during operation Based on the battery cell capacity information the initial value of chemical capacity should be entered in the Qmax n
61. rding third party products or services does not constitute a license from TI to use such products or services or a warranty or endorsement thereof Use of such information may require a license from a third party under the patents or other intellectual property of the third party or a license from TI under the patents or other intellectual property of TI Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties conditions limitations and notices Reproduction of this information with alteration is an unfair and deceptive business practice TI is not responsible or liable for such altered documentation Information of third parties may be subject to additional restrictions Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice TI is not responsible or liable for any such statements TI products are not authorized for use in safety critical applications such as life support where a failure of the TI product would reasonably be expected to cause severe personal injury or death unless officers of the parties have executed an agreement specifically governing such use Buyers represent that they have all necessary expertise in the safety
62. rement This impedance is compared with the associated Packn Ha and Defn profiles that correspond to the current RID If the impedance matches the Packn impedance then the Packn profile is used If not the bq27501 resets the Packn Ra data by copying the Defn Ra profile into the Packn Ha profile this operation overwrites the previously stored information The Impedance Track algorithm begins converging on the data for the new battery and storing it in the Packn Ra profile APPLICATION SPECIFIC INFORMATION Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 7 COMMUNICATIONS 7 1 PC INTERFACE The fuel gauge supports the standard read incremental read one byte write quick read and functions The 7 bit device address ADDR is the most significant 7 bits of the hex address and is fixed as 1010101 The 8 bit device address is therefore OxAA or OxAB for write or read respectively Host generated Fuel Gauge Generated S ADDR 6 0 OVA CMD 7 0 A DATA 7 0 o ADDR E6 0 1 DATA 7 0 1 byte write b quick read Isi ADDR S 0 CMD 7 0 ni ADDR 6 0 E Ammo 1 byte read S ADDR 6 0 CMD 7 0 A sr ADDR 6 0 1 A DATA 7 0 Al DATA 7 0 d incremental read S Start Sr Repeated Start
63. rtial reset was detected a RAM checksum is generated and compared against the previously stored checksum If the checksum values do not match the RAM is reinitialized a Full Reset The stored checksum is updated every time RAM is altered DEVICE RESET Generate Active RAM checksum value Stored checksum Reinitialize all Do the Checksum Values Match RAM NORMAL OPERATION Active RAM changed Store Generate New checksum checksum value Figure 5 3 Partial Reset Flow Diagram Submit Documentation Feedback FUNCTIONAL DESCRIPTION 29 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 5 8 2 WAKE UP COMPARATOR The wake up comparator is used to indicate a change cell current while the bq27500 1 is in either SLEEP or HIBERNATE modes Operation Configuration uses bits RSNS1 RSNSO to set the sense resistor selection Operation Configuration also uses the IWAKE bit to select one of two possible voltage threshold ranges for the given sense resistor selection An internal interrupt is generated when the threshold is breached in either charge or discharge directions Setting both RSNS1 and RSNSQ to disables this feature Table 5 4 Iwake Threshold Settings RSNS1 RSNSO IWAKE Vth SRP SRN 0 0 0 Disabled 0 0 1 Disabled 0 1 0 1 25 mV or 1 25 mV 0 1 1 2 5 mV 2 5 mV 1 0 0 2 5 mV 2 5 mV 1 0 1 5 mV or 5
64. several data flash variables that permit the user to customize the Impedance Track algorithm for optimized performance These variables are dependent upon the power characteristics of the application as well as the cell itself Load Mode Load Mode is used to select either the constant current or constant power model for the Impedance Track algorithm as used Load Select see Load Select When Load Mode is 0 the Constant Current Model is used default When 1 the Constant Power Model is used The LDMD bit of CONTROL STATUS reflects the status of Load Mode Load Select Load Select defines the type of power or current model to be used to compute load compensated capacity in the Impedance Track algorithm If Load Mode 0 Constant Current then the options presented in Table 5 1 are available Table 5 1 Constant Current Model Used When Load Mode 0 LoadSelect Value Current Model Used Average discharge current from previous cycle There is an internal register that records the average discharge 0 current through each entire discharge cycle previous average is stored in this register Present average discharge current This is the average discharge current from the beginning of this discharge 1 default cycle until present time Average Current based on AverageCurrent Current based off of a low pass filtered version of AverageCurrent 2 14s Design Capacity 5 C Rate based off of Design C
65. specifications per the terms of Texas Instruments standard warranty Production processing does not necessarily include testing of all parameters Copyright O 2007 Texas Instruments Incorporated 0427500 9427501 49 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 E These devices have limited built in ESD protection The leads should be shorted together or the device placed in 1 INTRODUCTION conductive foam during storage or handling to prevent electrostatic damage to the MOS gates 1 1 12 APPLICATIONS 13 2 2 2 4 AVAILABLE OPTIONS 2 2 DIAGRAMS 2 3 TERMINAL 3 ELECTRICAL SPECIFICATIONS 31 ABSOLUTE MAXIMUM RATINGS 3 2 RECOMMENDED OPERATING CONDITIONS 3 3 POWER ON 3 44 INTERNAL TEMPERATURE SENSOR CHARACTERISTICS 3 5 HIGH FREQUENCY OSCILLATOR 3 6 LOW FREQUENCY OSCILLATOR 3 7 INTEGRATING ADC COULOMB COUNTER CHARACTERISTICS 3 8 ADC TEMPERATURE AND CELL MEASUREMENT CHARACTERISTICS 3 9 FLA
66. t Documentation Feedback FUNCTIONAL DESCRIPTION 27 0427500 0427501 System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 a d Pd xit From HIBERNATE Communication Activity AND Comm address is for bq27500 1 OR Fi Battery Removed Control Status HIBERNATE is set to 0 HIBERNATE Disable all b032 subcircuits except GPIO Set BAD GD to high status Wakeup From HIBERNATE Communication Activity Al Comm address is NOT for bq27500 1 Icc Hibernate x Entry To HIBERNATE Host has set Control Status HIBERNATE 1 OR lt Hibernate Voltage EM 7 45 TEXAS INSTRUMENTS www ti com _ M Check for battery insertion CONSE from HALT state No gauging _ Flags BATDET N gt lcc Sleep BN Sie Entry to NORMAL N Flags IBALDET T Exit FromNORMAL X Flags BATDET 0 PA Fuel gauging and data updated every 1s Exit From SLEEP N Flags BATDET 0 Icc Normal BN Exit From SLEEP V AverageCurrent Sleep Current OR 1 Current is Detected above Entry to SLEEP Entry to SLEEP Operation Configuration SLEEP 1 1 AND N lAverageCurrent s Sleep Current Fuel gauging and data updated every 60 seconds lcc Sleep Figure 5 2 Power Mode Diagram 5 7 4 HIBERNATE MODE HIBERNATE mode should be used when the system equipmen
67. t n 128 127 0 0 1 C Calibration 107 Current 1 Deadband U1 0 255 3 mA Security 112 Codes 0 Usealed KeyO H2 0x0000 Oxffff Security 112 Codes 2 Usealed Key1 H2 0x0000 Oxffff Security 112 Codes 4 Full Access 0 H2 0x0000 Oxffff Security 112 Codes 6 Full Access Key1 H2 0x0000 Oxffff 5 FUNCTIONAL DESCRIPTION 5 1 FUEL GAUGING 20 The bq27500 1 measures the cell voltage temperature and current to determine battery SOC The bq27500 1 monitors charge and discharge activity by sensing the voltage across a small value resistor bmQ to 20 typ between the SRP and SRN pins and in series with the cell By integrating charge passing through the battery the cell s SOC is adjusted during battery charge or discharge The total battery capacity is found by comparing states of charge before and after applying the load with the amount of charge passed When an application load is applied the impedance of the cell is measured by comparing the OCV obtained from a predefined function for present SOC with the measured voltage under load Measurements of OCV and charge integration determine chemical state of charge and Chemical Capacity Qmax The initial Qmax values are taken from a cell manufacturers data sheet multiplied by the number of parallel cells It is also used for the value in Design Capacity The bq27500 1 acquires and updates the battery impedance profile during normal battery usage It uses this profile along with SOC an
68. t needs to enter a very low power state and minimal gauge power consumption is required This mode is ideal when a system equipment is set to its own SLEEP HIBERNATE or SHUTDOWN modes To enter HIBERNATE mode either the system must set the HIBERNATE bit of the CONTROL STATUS register OR the cell voltage must fall below Hibernate Voltage The gauge will remain in HIBERNATE mode until the battery is removed or the system issues direct IC command to the gauge Communication that is not directed to the gauge will not wake the gauge It is important that GD be set to disable status no battery charging discharging This prevents charger application from inadvertently charging the battery before an OCV reading can be taken It is the system s responsibility to wake the bq27500 1 after it has gone into HIBERNATE mode After waking the gauge can proceed with the initialization of the battery information OCV profile selection etc 28 FUNCTIONAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 5 8 POWER CONTROL 5 8 1 RESET FUNCTIONS When the 0427500 detects software reset RESET bit of Control initiated it determines the type of reset and increments the corresponding counter This information is accessible by issuing the command Control function with the RESET DATA subcommand As shown in Figure 5 3 if a pa
69. tested in production 3 9 DATA FLASH MEMORY CHARACTERISTICS Ta 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at 25 and Vec 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ton Data retention See 0 100 Flash programming write cycles See 0 20 000 Cycles twoRDPROG Word programming time See 0 2 ms lccPRoG Flash write supply current 5 10 mA 1 Specified by design Not production tested 3 10 lC COMPATIBLE INTERFACE COMMUNICATION TIMING CHARACTERISTICS T4 40 C to 85 C 2 4 V lt Voc lt 2 6 V Typical Values at T4 25 C and Vec 2 5 V unless otherwise noted PARAMETER TEST CONDITIONS MIN UNIT t SCL SDA rise time 1 us SCL SDA fall time 300 ns tw H SCL pulse width high 4 us tw L SCL pulse width low 4 7 us tsu STA Setup for repeated start 4 7 us la sTA Start to first falling edge of SCL 4 us lsu DAT Data setup time 250 ns Receive mode 0 lnDAT Data hold time ns Transmit mode 300 tsu STOP Setup time for stop 4 us Bus free time between stop and start 4 7 us fscL Clock frequency 10 100 kHz BUSERR Bus error timeout 17 3 21 2 5 6 ELECTRICAL SPECIFICATIONS Submit Documentation Feedback 0427500 49 Texas 0427501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 tsu STA tw H tw L t t BUF
70. tween SEALED UNSEALED and FULL ACCESS modes Each transition requires that a unique set of 2 keys be sent to the bq27500 1 via the Control control command The keys must be sent consecutively with no other data being written to the Control register in between Note that to avoid conflict the keys must be different from the codes presented in the CNTL DATA column of Table 4 2 Control subcommands When in SEALED mode the Control Status s SS bit is set but when the UNSEAL keys are correctly received by the bq27500 1 the SS bit is cleared When the FULL ACCESS keys are correctly received then the Control Status FAS bit is cleared Submit Documentation Feedback GENERAL DESCRIPTION 17 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 Both the sets of keys for each level are 2 bytes each in length and are stored in data flash The UNSEAL key stored at Unseal Key 0 and Unseal Key 1 and the FULL ACCESS key stored at Full Access Key 0 and Full Access Key 1 can only be updated when in FULL ACCESS mode The order of the bytes entered through the Control command is the reverse of what is read from the part For example if the 1st and 2nd word of Unseal Key 0 read returns 0x1234 and 0x5678 then the Control should supply 0x3412 and 0x7856 to unseal the part 4 6 DATA FLASH SUMMARY Table 4 7 summarizes the data flash locations available to the user including their
71. uel gauge to transition from UNSEALED state to SEALED state The fuel gauge should always be set to SEALED state for use in end equipment 4 1 1 1 13 IT ENABLE 0x0021 This command forces the fuel gauge to begin the Impedance Track M algorithm sets the active UpdateStatus n location to 0x04 and causes the VOK and QEN flags to be set in the CONTROL STATUS register VOK is cleared if the voltages are not suitable for a Qmax update Once set QEN cannot be cleared This command is only available when the fuel gauge is UNSEALED 4 1 1 1 14 IF CHECKSUM 0x0022 This command instructs the fuel gauge to compute the instruction flash checksum When the checksum has been calculated and stored then CONTROL STATUS CVS is set In UNSEALED mode the checksum value is returned to addresses 0x00 0x01 The checksum will not be calculated in SEALED mode however the checksum value can still be read Submit Documentation Feedback GENERAL DESCRIPTION 11 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 4 1 1 1 15 CAL MODE 0x0040 This command instructs the fuel gauge to enter calibration mode This command is only available when the fuel gauge is UNSEALED 4 1 1 1 16 RESET 0x0041 This command instructs the fuel gauge to perform a full reset This command is only available when the fuel gauge is UNSEALED 4 1 1 2 AtRate 0x02 0x03 The AtRate read write word function is the first ha
72. uration and user information The data flash can be accessed in several different ways depending on what mode the bq27500 1 is operating in and what data is being accessed Commonly accessed data flash memory locations frequently read by a system are conveniently accessed through specific instructions already described in Section 4 1 DATA COMMANDS These commands are available when the bq27500 1 is either in UNSEALED or SEALED modes Most data flash locations however are only accessible in UNSEALED mode by use of the bq27500 1 evaluation software or by data flash block transfers These locations should be optimized and or fixed during the development and manufacture processes They become part of a golden image file and can then be written to multiple battery packs Once established the values generally remain unchanged during end equipment operation To access data flash locations individually the block containing the desired data flash location s must be transferred to the command register locations where they can be read to the system or changed directly This is accomplished by sending the set up command BlockDataControl 0x61 with data 0x00 Up to 32 bytes of data can be read directly from the BlockData 0x40 0x5f externally altered then re written to the BlockData command space Alternatively specific locations can be read altered and re written if their corresponding offsets are used to index into the BlockData comma
73. urement input ADC input 5 Voc P Processor power input Decouple with 0 1uF capacitor minimum 6 Vss Vss P Device ground 7 SRP SRP IA Analog input pin connected to the internal coulomb counter where SRP is nearest the CELL connection Connect to 5 20mQ sense resistor 8 SRN SRN IA Analog input pin connected to the internal coulomb counter where SRN is nearest the PACK connection Connect to 5 20mQ sense resistor 9 NC RID 21 connection bq27500 Resistor ID input 09427501 Analog input with current sourcing capabilities 10 SDA SDA Slave serial communications data line for communication with system Master Open drain I O Use with 10kQ pull up resistor typical 11 SCL SCL Slave serial communications clock input line for communication with system Master Open drain I O Use with 10kQ pull up resistor typical BATGD BATGD Battery Good indicator Active ow by default though polarity can be configured through EA GE VEU RR the BATG_POL of Operation Configuration Open drain output 1 VO Digital Input Output IA Analog Input P Power Connection Submit Documentation Feedback DEVICE INFORMATION 3 0427500 0427501 33 Texas System Side Impedance Track Fuel Gauge INSTRUMENTS SLUS785 SEPTEMBER 2007 3 ELECTRICAL SPECIFICATIONS 3 4 ABSOLUTE MAXIMUM RATINGS over operating free air temperature range unless otherwise noted PARAMETER VALUE
74. y as periodic temperature updates are avoided during charging mode FUNCTIONAL DESCRIPTION Submit Documentation Feedback 0427500 49 Texas bq27501 INSTRUMENTS System Side Impedance Track Fuel Gauge SLUS785 SEPTEMBER 2007 5 7 POWER MODES 5 7 1 The bq27500 1 has four power modes NORMAL SLEEP HIBERNATE and BAT INSERT CHECK In NORMAL mode the bq27500 1 is fully powered and can execute any allowable task In SLEEP mode the fuel gauge exists in a reduced power state periodically taking measurements and performing calculations In HIBERNATE mode the fuel gauge is in its lowest power state but can be woken up by communication activity or certain 1 activity Finally the BAT INSERT CHECK mode is a powered up but low power halted state where the bq27500 1 resides when no battery is inserted into the system The relationship between these modes is shown in Figure 5 2 NORMAL MODE The fuel gauge is in NORMAL Mode when not in any other power mode During this mode AverageCurrent and Temperature measurements are taken and the interface data set is updated Decisions to change states are also made This mode is exited by activating a different power mode Because the gauge consumes the most power in NORMAL mode the Impedance Track algorithm minimizes the time the fuel gauge remains in this mode 5 7 2 SLEEP MODE SLEEP mode is entered automatically if the feature is enabled Operation Configur

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