Fujitsu MB39A105 User's Manual
Contents
1. X Ip x tr x fosc Ps 6 Off cycle switching loss Ps orr X p tf x fosc 5 6 Total loss Pr Pc Ps oy Ps oF Example Using the SANYO MCH3405 Input voltage 2 4 V output voltage Vo 9 V drain current Ip 0 94 A Oscillation frequency fosc 500 kHz L 6 8 uH drain source on resistance Ros on 160 tr 18 ns tf 2 8 ns Drain current Max Ip Mao Vox lo VIN Min Vo ViN Min p 100 ton Vo _ 9x0 25 2 4x 9 2 4 1 2 4 2 6 8 106 9 500 103 1 20 Drain current Min Ip min p Min VITE 2L ton 9x 0 25 2 4x 9 2 4 1 2 4 2 6 8 10 6 9 500 103 0 68 MB39A105 Pc lp2x x Duty 0 942x0 16x 224 0 104 W Vp X p x tr x fosc 6 9 x 0 94 x 18 x 10 9 x 500 x 103 6 0 013 W X D X tf x fosc 6 9 x 1 20 x 8 x 10 9 x 500 x 10 6 Ps 0 007 W Pc Ps oN Ps 0 104 0 013 0 007 0 124 W The above power dissipation figures for the MCH3405 is satisfied with ample margin at 0 8 W Inductors In selecting inductors it is of course essential not to apply more current than the rated capacity of the inductor but also to note that the lower limit for ripple current is a critical poi2. 7 5 kQ VCC 3 3 V 4 pd 4 0 35 gt a ii Icc 15 5 m 1 1 0 2 05 0 00 0 2 4 6 8 10 0 10 20 30 40 50 Power supply voltage Vcc V RT terminal current lar uA Error Amplifier Threshold Voltage vs Power Supply Voltage 1 0 T T Ta 25 C 0 9 5 VCC 0 8 07 06 05 O 55 0 4 03 lt gt 0 2 0 1 0 0 0 2 4 6 8 10 Power supply voltage Vcc Error Amplifier Threshold Voltage vs Triangular Wave Oscillation Frequency vs Ambient Temperature Power supply voltage 0 52 O 600 Ta 25 C RT 7 5 kQ t 7 5 m 051 os Qx 50 j 8 gt 9 2 050 500 lt _ Ga 2 049 5 g 450 k 0 48 m 400 40 20 0 20 40 60 80 100 1 2 3 4 5 6 7 Ambient temperature Ta C Power supply voltage Vcc V Continued MB39A105 Triangular Wa
3. FUJITSU SEMICONDUCTOR DS04 27233 2E ASSP For Power Supply Applications General Purpose DC DC Converter 1 ch DC DC Converter IC for low voltage MB39A105 DESCRIPTION The MB39A105 is 1 channel DC DC converter IC using pulse width modulation PWM This IC is ideal for up conversion The minimum operating voltage is low 1 8 V and the MB39A105 is best for built in power supply such as LCD monitors Also the short circuit protection detection output function prevents input output short on a chopper type up converter This product is covered by US Patent Number 6 147 477 FEATURES Power supply voltage range 1 8 V to 6 V Reference voltage accuracy 1 High frequency operation capability 1 MHz Max Built in standby function 0 uA Typ Built in timer latch short circuit protection circuit Built in short circuit protection detection output function Built in soft start circuit independent of loads Built in totem pole type output for Nch MOS FET Package TSSOP 8P Thickness 1 1 mm Max PACKAGE 8 pin plastic TSSOP FUJITSU MB39A105 PIN ASSIGNMENT INE CSCP VCC SCPOD TOP VIEW FPT 8P M05 FB RT GND OUT MB39A105 PIN DESCRIPTION Descriptions Error amplifiers Error Amp inverted input terminal Timer latch short circuit protection capacitor connection terminal Power suppl
4. 7 5 kQ Frequency temperature variation Afosc fosc Ta 0 C to 85 C 4 Soft start block CS Charge current 0 5 Error amplifier block Error Amp Threshold voltage FB 0 5 V Input bias current INE 0V Voltage gain DC Frequency band width 0 dB Output voltage Vo Output source current source FB 0 5V Output sink current 09 09 09 00 00 FB 0 5 V 6 PWM compar ator block PWM Comp Maximum duty cycle Dtr 7 5 7 Output block Drive Output source current source OUT 0 V Duty lt 5 t 1 foscxDuty Output sink current OUT 3 3 V Duty lt 5 t 1 foscxDuty Output ON resistor OUT 15 mA OUT 15 mA 8 General block Standby current RT OPEN Power supply current Standard design value 7 5 MB39A105 TYPICAL CHARACTERISTICS Power Supply Current vs Power Supply Voltage Power Supply Current vs RT Terminal Current 5 5 0 Ta 25 C Ta 25 C lt lt 45
5. While DC DC converter load conditions are stable the short circuit detection comparator output remains stable and the CSCP terminal pin 2 is held at soft start end voltage about 0 8 V If the load condition changes rapidly due to a short circuit of the load and the DC DC converter output voltage drops the output of the error amplifier usually goes over 0 9 V In that case the capacitor is charged further When the capacitor Csce is charged to about 1 0 V the latch is set and the external FET is turned off dead time is set to 100 At this time the latch input is closed and the CSCP terminal pin 2 is held at L level When CSCP terminal becomes L level SCPOD terminal Nch MOS FET becomes OFF SCPOD terminal pin 4 is held at L level and can be used as a short circuit operating detection signal during normal operation To reset the actuated protection circuit the power supply turn off and on again to lower the VCC terminal pin 3 voltage to 1 1 V Min or less Short circuit detection time tcscr tcsce s 0 23 x Timer latch short circuit protection circuit Vo FB 8 R1 Error INE 1 pos R2 T 0 5 V 0 88 uA 10 1 uA VREF SCP 0 9 V 425 to Drive CSCP 09v VREF 5 Latch UVLO 14 MB39A105 w G X G G G G G G D 5 S i D S e Soft start and short circuit protec
6. 06 Nch FET VDS 20 V Qg 4 5 nC SANYO MCH3405 D1 Diode VF 0 40 V atIF 1A SANYO SBS004 L1 Inductor 6 8 uH 1 4 A 144 SUMIDA CMD5D13 6R8 C1 C7 C9 Ceramics Condenser 0 1 uF 50 TDK C1608JB1H104K C2 to C6 NeoCapacitor 4 7 uF 10V NEC TOKIN TEPSLA21A475M8R Ceramics Condenser 0 22 uF 10V TDK C1608JB1A224K Resistor 7 5 KQ 0 5 ssm RR0816P 752 D Resistor 51 KQ 0 5 ssm RR0816P 513 D Resistor 43 0 5 ssm RR0816P 433 D Resistor 330 kQ 0 5 ssm RR0816P 334 D Resistor 22 0 5 ssm RR0816P 223 D Resistor 100 kQ 0 5 ssm RR0816P 104 D Note SANYO SANYO Electric Co Ltd SUMIDA SUMIDA Electric Co Ltd TDK TDK Corporation NEC TOKIN NEC TOKIN Corporation ssm SUSUMU Co Ltd 18 MB39A105 SELECTION OF COMPONENTS Nch MOS FET The N ch MOSFET for switching use should be rated for at least 20 more than the maximum output voltage To minimize continuity loss use a FET with low between the drain and source For high output voltage and high frequency operation on off cycle switching loss will be higher so that power dissipation must be considered In this application the SANYO MCH3405 is used Continuity loss on off switching loss and total loss are determined by the following formulas The selection must ensure that peak drain current does not exceed rated values Continuity loss Pc Pc Ip x Roson x Duty On cycle switching loss Ps
7. Dimensions in mm inches MB39A105 FUJITSU LIMITED All Rights Reserved The contents of this document are subject to change without notice Customers are advised to consult with FUJITSU sales representatives before ordering The information and circuit diagrams in this document are presented as examples of semiconductor device applications and are not intended to be incorporated in devices for actual use Also FUJITSU is unable to assume responsibility for infringement of any patent rights or other rights of third parties arising from the use of this information or circuit diagrams The products described in this document are designed developed and manufactured as contemplated for general use including without limitation ordinary industrial use general office use personal use and household use but are not designed developed and manufactured as contemplated 1 for use accompanying fatal risks or dangers that unless extremely high safety is secured could have a serious effect to the public and could lead directly to death personal injury severe physical damage or other loss i e nuclear reaction control in nuclear facility aircraft flight control air traffic control mass transport control medical life support system missile launch control in weapon system or 2 for use requiring extremely high reliability i e submersible repeater and artificial satellite Please note that Fujitsu will not be l
8. N OFF CTL H ON operating L OFF H ON 7 3 Protective Functions 1 Timer latch short circuit protection circuit SCP Short circuit detection comparator detects the error amplifier output voltage level If the load conditions for the DC DC converter are stable the short circuit protection comparator is kept in equilibrium condition because the error amplifier is free from output variation At this time the CSCP terminal pin 2 is held at the soft start end voltage about 0 8 V If the DC DC converter output voltage falls and error amplifier output is over 0 9 V the timer circuits are actuated to start charging the external capacitor Csce When the capacitor voltage reaches about 1 0 V the latch is set and the circuit is turned off the external FET and sets the dead time to 100 96 At this time latch input is closed and the CSCP terminal is held at the L level To reset the actuated protection circuit turn off and on the power supply again and set VCC terminal voltage 3 to 1 1 V Min or less See BSETTING TIME CONSTANT FOR TIMER LATCH SHORT CIRCUIT PRO TECTION CIRCUIT 2 Under voltage lockout protection circuit UVLO The transient state or a momentary decrease in supply voltage which occurs when the power supply is turned on may cause the IC to malfunction resulting in breakdown or degradation of the system To prevent such malfunctions under voltage lockout protection circuit detects a decrease in inter
9. an set a soft start by connecting soft start capacitors to the terminal pin 2 When IC starts Vcc gt UVLO threshold voltage the external soft start capacitors Cscr connected to CSCP terminal are charged at 11 uA The error amplifier output FB pin 8 is determined by comparison between the lower one of the potentials at two non inverted input terminals 0 5 V in an internal reference voltage CSCP terminal voltages and the inverted input terminal voltage INE pin 1 voltage The FB terminal voltage is decided for the soft start period by the comparison between 0 5 V in an internal reference voltage and the voltages of the CSCP terminal The DC DC converter output voltage rises in proportion to the CSCP terminal voltage as the soft start capacitor connected to the CSCP terminal is charged The soft start time is obtained from the following formula Soft start time ts time to output 100 ts s 0 045 x Csce uF CSCP terminal voltage gt Soft start time ts Soft Start Circuit Vo VREF 11 uA INE 1 Q R2 z Error Amp AN ser 05V CscP 8 FB 13 MB39A105 SSS SETTING TIME CONSTANT FOR TIMER LATCH SHORT CIRCUIT PROTECTION CIRCUIT The error amplifiers output level alaways does the comparison operation with the short circuit protection com parator SCP Comp to the reference voltage
10. be set up with consideration for common impedance Take appropriate static electricity measures Containers for semiconductor materials should have anti static protection or be made of conductive material After mounting printed circuit boards should be stored and shipped in conductive bags or containers Work platforms tools and instruments should be properly grounded Working personnel should be grounded with resistance of 250 to 1 between body and ground Do not apply negative voltages The use of negative voltages below 0 3 V may create parasitic transistors on LSI lines which can cause abnormal operation ORDERING INFORMATION Partnumber number si 8 E ded 25 MB39A105 G G 5 G UOI NE PACKAGE DIMENSION 8 pin plastic TSSOP 8 5 3 00 0 10 118 004 lt 0 127 0 03_ m NI 0050 001 J A 4 40 0 10 6 40 0 20 173 004 252 008 Details of A part ses 1 10 043 MAX Y N Y _ 0 22 0 10 H 009 004 0 54 021 _ m 004 004 0 65 026 d 0 10 004 1 95 077 2002 FUJITSU LIMITED 080135 1 1
11. he mean output current level and peak current is within peak surge current limits there is no problem In this application the SANYO SBS004 is used The diode mean current and diode peak current can be calculated by the following formulas Diode mean current loi Vo ViN Min gt lox 1 Vo Diode peak current Vox lo VIN Min VIN Min 2L ton lpp gt Example Using the SANYO SBS004 VR DC reverse voltage 15 V mean output current 1 0 A peak surge current 10 A VF forward voltage 0 40 V IF 1 0 A Vo VIN Min gt lox 1 Vo gt 0 25 x 1 0 733 gt 66 8 mA Vox lo VIN Min C VIN Min 2L ton lbp gt gt 1 20 A MB39A105 Smoothing Capacitor The smoothing capacitor is an indispensable element for reducing ripple voltage in output In selecting a smooth ing capacitor it is essential to consider equivalent series resistance ESR and allowable ripple current Higher ESR means higher ripple voltage so that to reduce ripple voltage it is necessary to select a capacitor with low ESR However the use of a capacitor with low ESR can have substantial effects on loop phase characteristics and therefore requires attention to system stability Care should also be taken to use a capacity with sufficient margin for allowable ripple current This application uses the TEPSLA21A475M8R NEC TOKIN The ESR capacitance value and ripple cu
12. iable against you and or any third party for any claims or damages arising in connection with above mentioned uses of the products Any semiconductor devices have an inherent chance of failure You must protect against injury damage or loss from such failures by incorporating safety design measures into your facility and equipment such as redundancy fire protection and prevention of over current levels and other abnormal operating conditions If any products described in this document represent goods or technologies subject to certain restrictions on export under the Foreign Exchange and Foreign Trade Law of Japan the prior authorization by Japanese government will be required for export of those products from Japan F0209 FUJITSU LIMITED Printed in Japan
13. nal reference voltage with respect to the power supply voltage turns off the output FET and sets the dead time to 10096 while holding the CSCP terminal pin 2 at the L level The circuit restores the output transistor to normal when the supply voltage reaches the threshold voltage of the undervoltage lockout protection circuit 3 Short circuit protection detection output function Connecting the Pch MOS FET to SCPOD terminal pin 4 turns off the Pch MOS FET when the short circuit protection is detected or under voltage lockout protection circuit operate This allows you to prevent the short circuit between the input and output when the short circuit protection is detected thus preventing the input voltage from occurring in the output region in the standby state 4 Protection circuit operating function table This table refers to output condition when protection circuit is operating Short circuit protection circuit Under voltage lockout protection circuit 11 MB39A105 SETTING THE OUTPUT VOLTAGE Output Voltage Setting Circuit SETTING THE TRIANGULAR OSCILLATION FREQUENCY The triangular oscillation frequency is determined by the timing resistor Rr connected to the RT terminal pin 7 Triangular oscillation frequency fosc 3750 fosc kHz Rr MB39A105 G SETTING THE SOFT START TIMES To prevent rush currents when the IC is turned on you c
14. nt that if reached will cause discontinuous operation and a considerable drop in efficiency This can be prevented by choosing a higher inductance value which will enable continuous operation under light loads Note that if the inductance value is too high however direct current resistance DCR is increased and this will also reduce efficiency The inductance must be set at the point where efficiency is greatest Note also that the DC superimposition characteristics become worse as the load current value approaches the rated current value of the inductor so that the inductance value is reduced and ripple current increases causing loss of efficiency The selection of rated current value and inductance value will vary depending on where the point of peak efficiency lies with respect to load current Inductance values are determined by the following formulas Inductance value L Vin2 MB39A105 Example VIN Max 2 2loVo 42 9 4 1 9x025x8 89 500x10 ton gt 9 95 uH Inductance values derived from the above formulas are values that provide sufficient margin for continuous operation at maximum load current but at which continuous operation is not possible at light loads It is therefore necessary to determine the load level at which continuous operation becomes possible In this application the Sumida CMD5D13 6R8 is used At 6 8 WH the load current value under continuous operating conditions is determined by the f
15. ollowing formula Load current value under continuous operating conditions lo VIN 2 lo 2 vV ton 42 9 4 1 2 6 8 10 9 9 500 103 gt 145 2 determine whether the current through the inductor is within rated values it is necessary to determine the peak value of the ripple current as well as the peak to peak values of the ripple current that affect the output ripple voltage The peak value and peak to peak value of the ripple current can be determined by the following formulas Peak value IL gt Vo x lo Vin ion dome Vo Vin 2L Vo Peak to peak value Al AlL ViN ton Example Using the CMD5D13 6R8 6 8 uH allowable tolerance 20 rated current 1 4 Peak value Vo x lo Vo Vin l 2 ViN T 2L ton ton t 9 x 0 25 n 2 4 x 9 2 4 1 2 4 2 6 8 10 9 500 x 103 gt 41 20 A MB39A105 Peak to peak value Mise _ 4x 9 4 1 6 8 10 8 9 x 500 x 103 0 654 A Flyback diode The flyback diode is generally used as a Shottky barrier diode SBD when the reverse voltage to the diode is less than 40V The SBD has the characteristics of higher speed in terms of faster reverse recovery time and lower forward voltage and is ideal for achieving high efficiency As long as the DC reverse voltage is sufficiently higher than the output voltage the average current flowing through the diode is within t
16. or Rr RT terminal Short circuit detection capacitor Csce CSCP terminal Operating ambient temperature Ta WARNING The recommended operating conditions are required in order to ensure the normal operation of the semiconductor device All of the device s electrical characteristics are warranted when the device is operated within these ranges Always use semiconductor devices within their recommended operating condition ranges Operation outside these ranges may adversely affect reliability and could result in device failure No warranty is made with respect to uses operating conditions or combinations not represented on the data sheet Users considering application outside the listed conditions are advised to contact their FUJITSU representatives beforehand MB39A1 ELECTRICAL CHARACTERISTICS 05 Parameter Conditions VCC 3 3 Ta 25 1 Under voltage lockout protection circuit block UVLO Threshold voltage VCC 2 Short circuit protection block SCP Threshold voltage Short circuit detection time setting difference voltage AVcscP Input source current lcscP CSCP 0 85 V Reset voltage Vnsr VCC SCPOD terminal output leak current ILEAK SCPOD 3 3 V SCPOD terminal output on resistor Ron SCPOD 1 mA 3 Triangular wave oscillator block OSC Oscillation frequency fosc RT
17. rrent can be calculated from the following formulas Equivalent Series Resistance ESR AVo 1 ESR Capacitance value C Al C gt 3x AVo AILXESR Ripple current AIC ViN L AIC gt ton Example Using the TEPSLA21A475M8R Three piecies are parallel Rated voltage 10 V ESR 500 maximum allowable ripple current 1 Ap p Equivalent series resistance AVo 1 ESR Si 2n CL 2 0 18 1 0 654 500 x 103 x 14 1 x 10 lt 252 7 Capacitance value C Al gt AL XESR 0 39 2nx500x103x 0 18 0 654 x 0 167 gt 2 94 uF Ripple current AIC Vin L 4x 9 4 1 6 8x10 x9 500 x 103 AIC gt ton V gt 0 654 Ap p MB39A105 REFERENCE DATA Conversion Efficiency vs Load current 100 25 PN 9 V output MY x 90 lt 5 r 4 80 5 77 5 4 5 2 Vy Vin 1 8 V 5 PA r Nin 3 3 V gt 60 7 Vin 6 0V 5 4 9 50 40 30 1m 10m 100m 1 Load current I A Switching Wave Form 25 VIN 3 3 V Vo 9 V lo 100 t us 24 MB39A105 USAGE PRECAUTION e Printed circuit board ground lines should
18. the PWM comparator in the IC 2 Error amplifier block Error Amp1 Error Amp2 The error amplifier detects the DC DC converter output voltage and outputs PWM control signals In addition an arbitrary loop gain can be set by connecting a feedback resistor and capacitor from the output terminal to inverted input terminal of the error amplifier enabling stable phase compensation to the system Also it is possible to prevent rush current at power supply start up by connecting a soft start capacitor with the CSCP terminal pin 2 which is the non inverted input terminal for Error Amp The use of Error Amp for soft start detection makes it possible for a system to operate on a fixed soft start time that is independent of the output load on the DC DC converter 3 PWM comparator block PWM Comp The PWM comparator is a voltage to pulse width modulator that controls the output duty depending on the input output voltage The comparator keeps output transistor on while the error amplifier output voltage and the DTC voltage remain higher than the triangular wave voltage 4 Output block Drive The output block is in the totem pole configuration capable of driving an external N channel MOS FET MB39A105 2 Power Control Function A switch in series with a resistor connected with the RT terminal pin 7 allows you to turn on or turn off the power On off setting conditions of power supply RT Lem L OFF standby O
19. tion circuit timing chart FB voltage pee sess sss 1 0 V M UNA E 8 L CSCP voltage 1 0 8 V 1 beT n 1 1 r cy uuum 1 1 I sassa i Output MM LL ou shot Output short E Soft start time Short circuit detection time t ts tcscP 15 MB39A105 I O EQUIVALENT CIRCUIT Soft start block CS gt gt vec 3 ESD A protection ESD element protection CSCP element ESD protection GNE element Triangular wave oscillator block RT gt VCC 4 0 33 V GND 4 Output block Short circuit protection circuit block SCP gt VCC 4 CSCP 1 0 V GND 4 Error amplifier block SCPOD VCC J 17 110 440 NO MB39A105 O 001 n LLH go t NO H 430 1 Es ONT 3dJO NO d3HA a 1 T A09 jueuno 1H NIA LLL 01411 zy zy ro 10 90 159 O t K dwy A e A 0 6 8 9 ON 13 JjNI VA 068 OM 9H SH 001 41 zy zv 3r 9H 9 19 APPLICATION EXAMPLE MB39A105 PARTS LIST COMPONENT ITEM SPECIFICATION VENDOR PARTS No Q1 Pch FET VDS 20 V ID 2 A Max SANYO MCH33
20. ve Oscillation Frequency Triangular Wave Oscillation Frequency vs Timing Resistor vs Ambient Temperature 10000 600 _ Ta 425 01 VCC 33V Sm MEME 7 5 or 550 9 x o 2 1000 lt 8 gt gt 49 z 9 gt 500 a ry F C So S 5 9 100 52 S Do 450 E 10 400 1 10 100 40 20 0 20 40 60 80 100 Timing resistor Rr kQ Ambient temperature Ta C Max On Duty vs Triangular Wave Oscillation Frequency 100 T T TTTTT Ta 25 C 95 VCC 3 3 V 9 90 85 x 80 gt 75 70 10 100 1000 10000 Triangular wave oscillation frequency fosc kHz Error Amplifier Gain and Phase vs Frequency 40 180 7 240 W 20 90 10 ao 10 D gt T OUT bo lt N 9 40 10 pa 10koz OUT 20 90 Error Amp 30 1 24 V 40 180 T T 100 10k 100k 1M 10M Frequency f Hz Continued Continued MB39A105 Power dissipation Pp mW Power Dissipation vs Ambient Temperature gt AM o oo 200 100 20 0 2 40 60 80 Ambient temperature Ta C 100 MB39A105 FUNCTIONS 1 DC DC Converter Functions 1 Triangular wave oscillator block OSC The triangular wave oscillator incorporates a timing resistor connected to RT terminal pin 7 to generate triangular oscillation waveform amplitude of 0 3 V to 0 7 V The triangular waveforms are input to
21. y terminal Open drain output terminal for short circuit protection detection During timer latch short circuit protection operation Output High Z During normal operation Output L External Nch FET gate drive terminal Ground terminal Triangular wave oscillation frequency setting resistor connection terminal Error Amplifier Error Amp output terminal MB39A105 BLOCK DIAGRAM 777 Error Amp SCPOD lo 400 mA at VCC 3 3 V RT Current Power VREF ON OFF CTL MB39A105 ABSOLUTE MAXIMUM RATINGS Parameter Power supply voltage Condition VCC terminal Output current OUT terminal Output peak current Duty lt 5 t 1 foscxDuty Power dissipation lt 25 Storage temperature The packages are mounted on the epoxy board 10 cm x 10 WARNING Semiconductor devices can be permanently damaged by application of stress voltage current temperature etc in excess of absolute maximum ratings Do not exceed these ratings RECOMMENDED OPERATING CONDITIONS Parameter Power supply voltage Condition VCC terminal Input voltage SCPOD terminal output voltage VscPoD NE terminal SCPOD terminal SCPOD terminal output current IscPor SCPOD terminal Output current lo OUT terminal Oscillation frequency fosc Timing resist
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