Ricoh RH5RH13B User's Manual
Contents
1. gt gt g o gt 2 2 e 1 10 20 30 40 50 60 70 80 90 Output Current lour mA RH5RH502B L 28uH 120 Ripple Voltage Vr mV p p 1 50 100 150 200 250 Output Current lour mA 5 Start up Hold on Voltage vs Output Current Topt 25 C Start up Hold on Voltage Vstart Vhold V RH5RH301A PP L 120uH 1 2 1 0 0 8 i AE 0 4 0 2 0 0 10 20 30 Output Current lour mA RH5RH501A L 120uH 0 10 20 30 Output Current lout mA Start up Hold on Voltage Vstart Vhold V RICON RH5RH302B 14 L 28uH 1 2 1 0 Vstart 0 8 0 6 0 4 Vhold 0 2 0 20 40 60 80 100 Output Current lour mA Start up Hold on Voltage Vstart Vhold V 6 Output Voltage vs Temperature lour 10mA Vin 2V L 120uH RH5RH301A 3 2 3 1 3 0 2 9 Output Voltage Vout V 2 8 2 7 40 20 0 20 40 60 80 100 Temperature 10 Vin 2V L 284uH RH5RH302B 3 2 3 1 3 0 2 9 2 8 Output Voltage Vout V 2 7 40 20 0 20 40 60 80 100 Temperature Start up Hold on Voltage Vstart Vhold Output Voltage Vout V Output Voltage Vout RH5RH RH5RH502B 14 L 28uH 1 2 Vstart 1 0 0 8 0 6 0 4 Vhold 0 2 20 40 60 80 100 O2. Level 2 0 8V lt Vout lt 1 5V V mee mmn ev Oscillator Maximum Duty on Vix L side 70 90 Cycle Time required for the rising of VOUT up to Unless otherwise provided VIN 1 8V Vss 0V IouT 10mA Topt 25 C and use External Circuit of Typical Application FIG 3 Supply Current 2 fosc Soft Start Time Note 1 Soft Start Circuit is operated in the following sequence 1 VIN is applied 2 The voltage Vref of the reference voltage unit is maintained at OV for about 200ps after the application of VIN 3 The output of Error Amp is raised to level during the maintenance of the voltage Vref of the reference voltage unit 4 After the rise of Vref the output of Internal Error Amp is gradually decreased to an appropriate value by the function of Internal Phase Com pensation Circuit and the Output Voltage is gradually increased in accordance with the gradual decrease of the output of Internal Error Amp Note 2 is gradually increased after Lx Switch is turned ON In accordance with the increase of VLx is also increased When VLx reaches VLxlim Lx Switch is turned OFF by an Lx Switch Protection Circuit RICON RH5RH e RH5RH503B VOUT 5 0V Coma omm m oe m n e Tar dme e ow meme 0 EA fas os v mayman v Sete K
3. RICON RH5RH 13 Oscillator Frequency vs Temperature RH5RH301A lour 10mA RH5RH501A lour 10mA Vin 2V Vin 3V L 120uH L 120uH 29 100 H N N 90 90 9 80 8 80 2 70 70 gt gt 60 60 50 2 50 40 40 LL LL 5 30 5 30 6 20 8 20 10 9 10 O o o 40 20 0 20 40 60 80 100 40 20 0 20 40 60 80 100 Temperature Topt Temperature RH5RH302B lour 10mA RH5RH502B lour 10mA Vin 2V Vin 3V L 28uH 140 H _ 140 L 28uH T T lt 120 120 2 2 2 100 2 100 gt gt S 80 5 80 8 60 8 60 LL LL 5 40 5 40 s 9 20 9 20 0 0 40 20 0 20 40 60 80 100 40 20 0 20 40 60 80 100 Temperature Temperature Topt C 14 Oscillator Duty Cycle vs Temperature RH5RH301A lour 10mA RH5RH501A lour 10mA Vin 2V Vin 3V L 120pH L 120pH g 100 Q 100 90 9 90 G G gt gt 80 2 80 gt 5 70 70 8 60 2 60 5 o 2 N O 650 O 50 40 20 0 20 40 60 80 40 20 0 20 40 60 80 Temperature Temperature RICOH 19 RH5RH RH5RH302B 10 RH5RH502B 10 100 L 28uH L 28uH 22 90 8 90 G G gt gt 2 80 3 80 2 70 70 8 60 60 9 5 50 8 so 40 20 0 20 4
4. Oscillator Maximum Duty on side Soft Start Time Time required for the rising of VOUT up to Vix Voltage Limit Lx Switch ON Unless otherwise provided VIN 1 8V Vss 0V IouT 10mA Topt 25 C and use External Circuit of Typical Application FIG 1 Note 1 Note 2 Soft Start Circuit is operated in the following sequence 1 ViN is applied 2 The voltage Vref of the reference voltage unit is maintained at OV for about 200us after the application of VIN 3 The output of Error Amp is raised to level during the maintenance of the voltage Vref of the reference voltage unit 4 After the rise of Vref the output of Internal Error Amp is gradually decreased to an appropriate value by the function of Internal Phase Compensation Circuit and the Output Voltage is gradually increased in accordance with the gradual decrease of the output of Internal Error Amp ILx is gradually increased after Lx Switch is turned ON In accordance with the increase of ILx VLx is also increased When VLx reaches VLXlim Lx Switch is turned OFF by an Lx Switch Protection Circuit RICOH RH5RH e RH5RH501A Vout 5 0V Symbol Item Conditions Output Voltage Input Voltage Vstart Start up Voltage Tout 1mA Vin 0 2V Vhold Hold on Voltage Tout 1mA Vin 2 0V IDD1 Supply Current 1 To be measured at OUT Pin excluding Switching Current To be measured at OUT Pin Ipp2 Sup
5. PON POFF T VOUuT IOUT POUT When the above Equation is solved for IOUT Iour ViN tonc 2 L T VOUT VIN EVIN Iconst VOUT mm HH Equation 8 The peak current which flows through L LxTr SD is ILriiaxzVIN t0n LE cODSl Equation 9 From Equations 6 and 9 the larger the value of L the smaller the load current at which the operation enters into the continuous mode and the smaller the difference between ILmax and ILmin and the smaller the value of ILmax Therefore when the load current is the same the larger the value of L the easier the selection of peripheral components with a small allowable current becomes and the smaller the ripple of the peripheral components can be made In this case however it must be noted from Equation 6 that IOUT becomes small when the allowable cur rent of the inductor is small or when VIN is so small that the operation cannot enter into the continuous mode The above explanation is directed to the calculation in an ideal case where there is no energy loss caused by the resistance in the external components and LxSW In an actual case the maximum output current will be 50 to 80 of the above calculated maximum output current In particular care must be taken because VIN is decreased in an amount corresponding to the voltage drop caused bv LxSW when IL is large or VIN is low Furthermore it is required that with respect to Vout Vf of the diode about 0 3V in t
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7. 50 50 40 40 0 50 100 150 0 50 100 150 Output Current lout mA Output Current lour mA RH5RH302B TT RH5RH502B 100 100 5 5 Vin 1 5V u o 0 0 200 400 600 0 500 1000 Output Current lour mA RICON Output Current lour mA RH5RH 3 Supply Curret No Load vs Input Voltage RH5RH301A RH5RH301A 70 L 120uH 70 L 270uH 60 60 5 50 5 s 40 40 30 5 30 20 ES 20 s 3 a 10 a 10 0 0 1 0 1 2 1 4 1 6 1 8 2 0 1 0 1 2 1 4 1 6 1 8 2 0 Input Voltage Vin V Input Voltage Vin V RH5RH501A RH5RH501A L 270uH 200 i ila 200 0 lt 150 5 150 5 100 5 100 8 50 a 50 2 5 n 42 0 0 Input Voltage Vin V Input Voltage Vin V 4 Output Current vs Ripple Voltage RH5RH301A L 120uH RH5RH501A L 120uH 80 100 90 a 70 2 0V gt gt 80 3 0V 4 0V E m 3 0V 70 gt 50 0 9 5 60 2 0V gt 40 50 5 30 5 40 Vin 0 9V 2 20 e 30 8 8 20 0 0 1 5 10 20 30 40 50 60 70 80 90 100 1 5 10 20 30 40 50 60 70 80 90 100 Output Current lour mA Output Current lour mA RICOH 15 16 RH5RH Ripple Voltage Vr mV p p Ripple Voltage Vr mV p p RH5RH301A 1 10 20 30 40 50 60 70 80 Output Current lour mA RH5RH302B 1 50 100 150 200 Output Current lour mA
8. Pons IL t dt f P Viv t L dt SVIN ton 2 L seen nennen ener Equation 3 In the case of the step up DC DC converter the energy is also supplied from the input power source at the time of OFF Thus Porr Vin IL t dt 2 Vour VtN t L dt VIN VOUT VIN topen 2 L Here topen VIN ton VOUT VIN from Equation 1 and when this is substituted into the above equation Equation 4 Input power is PON PoFF T When this is converted in its entirely to the output PIN PON POFF T VOUT IOUT POUT Equation 5 Equation 6 can be obtained as follows by solving Equation 5 for IouT by substituting Equations 3 and 4 into Equation 5 2 1 Equation 6 The peak current which flows through L LxTr SD is ILmax VIN 3 ton L EP TOO IA OI Equation 7 RIGO T 12 RH5RH Therefore it is necessary that the setting of the input output conditions and the selection of peripheral compo nents should be made with ILmax taken into consideration Output Current in Continuous Conduction Mode When the operation enters into the continuous conduction mode by increasing the IouT ILmin becomes equal to Iconst gt 0 and this current always flows through the inductor Therefore VIN Iconst is added to PIN in Equation 5 Thus PIN VIN Iconst
9. 0 60 80 40 20 0 20 40 60 80 Temperature Topt Temperature Topt C 15 Vix Voltage Limit vs Temperature RH5RH501A 12 5 1 0 26 gt 08 5 0 6 04 gt 0 2 gt 0 0 40 20 0 20 40 60 80 16 EXT Output Current vs Temperature 17 EXT L Output Current vs Temperature RH5RH501A RH5RH501A 10 10 EXT H Output Current o B EXT L Output Current lExTL MA 40 20 0 20 40 60 80 40 20 0 20 40 60 80 Temperature Temperature RICON RH5RH 18 Load Transient Response RH5RH301A lour 1mA 30mA RH5RH501A lour 1mA 30mA Vin 2V Vin 3V 240 7 0 s E 210 6 5 210 180 lt 60 180 lt 5 T 5 5 150 3 5 55 Voltage 150 3 120 5 8 120 5 2 9 6 gt 90 69 5 5 5 B 8 e 8 30 9 30 9 0 3 0 0 0 20 40 60 80 0 20 40 60 80 Time t ms Time t ms RH5RH302B jouT 1mA 30mA RH5RH502B lour 1MA 30mA Vin 2V Vin 3V L 28uH 5 0 7 0 H 240 4 5 210 40 180 5 3 9 35 8 gt Output Voltage4 150 3 3 0 9 120 gt gt 25 gt 90 E 5 5 20 5 60 8 3 2 Output Current 2 O 15 9 30 9 1 0 0 0 0 20 40 60 80 Time t
10. 4 ELECTRICAL CHARACTERITICS 5 OPERATION OF STEP UP DC DC CONVERTER 10 TYPICAL 13 1 Output Voltage vs Output Current sss 13 2 Efficiencv vs Output Current 14 3 Supply Current No Load vs Input Voltage MM 15 4 Output Current vs Ripple Voltage 15 5 Start up Hold on Voltage VS Output Current Topt 25 C TET C TTL LLLI III 1 6 6 Output Voltage vs Temperature I nnne nnn nnn 17 7 Start up Voltage vs Temperature n nnne nnn nnn nnne 18 8 Hold on Voltage vs Temperature MM Hn 18 9 Supply Current 1 vs Temperature nn nnn n nnn 18 10 Supply Current 2 vs Temperature nnne nnn nnne 18 11 Lx Switching Current vs Temperature s 18 12 Lx Leakage Current vs Temperature MH 18 13 Oscillator Frequency vs Temperature enn 19 14 Oscillator Duty Cycle vs Temperature HH 19 15 Vix Voltage Limit vs I III Ie Inn nenne nnns 20 16 EXT H Output Current vs Temperature 20 17 EXT L Output Current vs Temperature MM nnn 20 18 Load Transient Response s I
11. 80dB and Phase Comp Phase Compensation Circuit provides the frequency characteristics including the 1st pole fp 0 25Hz and the zero point fz 2 5kHz Furthermore another zero point fz 1 0kHz is also obtained by the resistors and a capacitor connected to the OUT pin Note Lx Pin gt only for RH5RHXX1A and RHSRHXX3B EXT only for RH5RHXX2B and RHSRHXX3B CE Pin only for RHSRHxx3B SELECTION GUIDE In RH5RH Series the output voltage the driver and the taping type for the ICs can be selected at the user s request The selection can be made by designating the part number as shown below RH5RHXXXX XX lt Part Number TT Y a b c Setting Output Voltage VOUT Stepwise setting with a step of 0 1V in the range of 2 7V to 7 5V is possible Designation of Driver 1A Internal Lx Tr Driver Oscillator Frequency 50kHz 2B External Tr Driver Oscillator Frequency 100kHz 3B Internal Tr External Tr selectively available Oscillator Frequency 100kHz with chip enable function Designation of Taping Type Ex SOT 89 TI T2 SOT 89 5 T1 T2 refer to Taping Specifications 1 is prescribed as a standard For example the product with Output Voltage 5 0V the External Driver the Oscillator Frequency 100kHz and Taping Type T1 is designated by Part Number RH5RH502B T1 RICON RH5RH PIN CONFIGURATION SOT 89 SOT 89 5 mark side LI 1 2 3
12. H5RHXX3B IC also includes an internal chip enable circuit so that it is possible to set the standby sup ply current at 0 5 These RH5RHXX1A XX2B XX3B ICs are suitable for use with battery powered instruments with low noise and low supply current FEATURES e Small Number of External Components Only an inductor a diode and a capacitor RH5RHXX1A Low Supplv Current 15 RH5RH301A e Low Ripple and Low Noise e Low Start up Voltage when the output current is ImA 777777 MAX 0 9V High Output Voltage Accuracy 2 5 High Efficiency tin clap TT 85 e Low Temperature Drift Coefficient of Output Voltage 7777 50 ppm C MIN 500us Small Packages SOT 89 RH5RHXX1A RH5RHXX2B SOT 89 5 RH5RHXX3B APPLICATIONS Power source for battery powered equipment Power source for cameras camcorders VCRs PDAs electronic data banks and hand held communication equipment Power source for instruments which require low noise and low supply current such as hand held audio equip ment Power source for appliances which require higher cell voltage than that of batteries used in the appliances RICOH RH5RH BLOCK DIAGRAM Error Amp Error Amplifier has a DC gain of
13. I IH nne annee rr ne nens 21 19 Distribution of Output Voltage MH HH 22 20 Distribution of Oscillator Frequency III Innern 22 TVPICAL APPLICATIONS 23 RH5RHXXAA 23 o RHSRHXXOB III 23 5 24 s CE pin Drive Circuittt 22 APPLICATION CIRCUITS rasasasanausasasananansasanananauausanananauauausanananauauausananauauausuanan 26 12V Step up 26 ta Step down Circuit 26 Step up Step down Circuit with Flyback rasansasasasasansusasanananausasasasananausasanananansasananauauuuauuan 27 DIMENSIONS BARARARARARRARARARARARRRRARARARARRRRARRRARRRRRARSASRSERSRRSARRRRRRRRRRRRRRR RR HG 28 TAPING SPECIFICATIONS rasasasausasasasanansusananananausasasananauusuuanananananansananauauausuuan 28 0 PWM STEP UP CONVERTER RH5RHXX1A XX2B Xx3B SERIES OUTLINE The RH5RHXX1A X X2B XX3B Series PWM Step up DC DC converter ICs by CMOS process The RH5RHXX 1A IC consists of an oscillator a PWM control circuit a driver transistor Lx switch a refer ence voltage unit an error amplifier a phase compensat
14. Input Power Source thereto so that a higher output voltage than the input voltage is obtained The operation will be explained with reference to the following diagrams lt Basic Circuits gt lt Current through L gt u Pt cR ILmax I 1 ton Lx Tr CL T 1 fosc Step 1 LxTr is turned ON and current IL 11 flows so that energy is charged in L At this moment IL il is increased from ILmin 0 to reach ILmax in proportion to the on time period ton of LxTr Step 2 When LxTr is turned OFF Schottky diode SD is turned ON in order that L maintains IL at ILmax so that current IL 12 is released Step 3 IL i2 is gradually decreased and in the case of discontinuous mode IL reaches ILmin 0 after a time period of topen so that SD is turned OFF However in the case of a continuous mode which will be mentioned later the time period toff runs out before IL reaches ILmin 0 so that LxTr is turned ON in the next cycle and SD is turned OFF In this case ILmin does not reach zero and IL i1 increases from ILmin gt 0 In the case of PWM control system the output voltage is maintained constant by controlling the on time peri od ton with the oscillator frequency fosc being maintained constant Discontinuous Conduction Mode and Continuous Conduction Mode In the above two diagrams the maximum value ILmax and the minimum value ILmin of the current which flows through t
15. KT foo To be measured at OUT pin Supply Current 2 VIN 5 5V E 0 EXT T Output Current SETTE fosc Oscillator Frequency Maxdty Oscillator Maximum Duty on Vix 17 side Cycle Time required for the rising of VOUT up to 5V Unless otherwise provided VIN 3V Vss 0V IouT 10mA Topt 25 C and use External Circuit of Typical Application FIG 3 tstart Soft Start Time Note 1 Soft Start Circuit is operated in the following sequence 1 VIN is applied 2 The voltage Vref of the reference voltage unit is maintained at OV for about 200us after the application of VIN 3 The output of Error Amp is raised to level during the maintenance of the voltage Vref of the reference voltage unit 4 After the rise of Vref the output of Internal Error Amp is gradually decreased to an appropriate value by the function of Internal Phase Com pensation Circuit and the Output Voltage is gradually increased in accordance with the gradual decrease of the output of Internal Error Amp Note 2 lx is gradually increased after Lx Switch is turned ON In accordance with the increase of ILx is also increased When Vix reaches VLxlim Lx Switch is turned OFF by an Lx Switch Protection Circuit RICOH RH5RH OPERATION OF STEP UP DC DC CONVERTER Step up DC DC Converter charges energy in the inductor when Lx Transistor LxTr is on and discharges the energy with the addition of the energy from
16. PIN DESCRIPTION 1 1 5 Vss Ground Pin 2 2 2 OUT Step up Output Pin Power Supply for device itself RICOH RH5RH ABSOLUTE MAXIMUM RATINGS EXT Pin Voltage 0 3 to VouT4 0 3 CE Pin Voltage 0 3 to VouT 0 3 Lx Pin Output Current 250 EXT Pin Current 50 Operating Temperature Range 30 to 80 E Tstg Storage Temperature Range 55 to 125 Tsolder Lead Temperature Soldering 260 C 10s Note 1 Applicable to RHS5RHXX1A and 5 Note 2 Applicable to 2 and RH5RHXX3B Note Applicable to RH5RHXX3B ABSOLUTE MAXIMUM RATINGS Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under any conditions Moreover such values for any two items must not be reached simultaneously Operation above these absolute maximum ratings may cause degradation or permanent damage to the device These are stress ratings only and do not necessarily imply functional operation below these limits RICON RH5RH ELECTRICAL CHARACTERISTICS e RHSRH301A KT L1 LRL Start up Voltage Iour21mA VIN 022V Vhold Vour 3 0V Hold on Voltage IOUT 1mA VIN 20V IDD1 To be measured at OUT Pin excluding Switching Current To be measured at OUT Pin Supply Current 2 excluding Switching Current VIN 3 5V Supplv Current 1 Lx Switching Current Lx Leakage Current Vix 6V VIN 3 5V Oscillator Frequency
17. PWM STEP UP DC DC CONVERTER RH5RHXX1AM xx2B Xxx3B SERIES APPLICATION MANUAL RICOR ELECTRONIC DEVICES DIVISION NO EA 023 9803 NOTICE The products and the product specifications described in this application manual are subject to change or dis continuation of production without notice for reasons such as improvement Therefore before deciding to use the products please refer to Ricoh sales representatives for the latest information thereon This application manual mav not be copied or otherwise reproduced in whole or in part without prior written con sent of Ricoh Please be sure to take anv necessarv formalities under relevant laws or regulations before exporting or other wise taking out of vour countrv the products or the technical information described herein The technical information described in this application manual shows tvpical characteristics of and example application circuits for the products The release of such information is not to be construed as a warrantv ofora grant of license under Ricoh s or anv third partv s intellectual propertv rights or anv other rights The products listed in this document are intended and designed for use as general electronic components in standard applications office equipment computer equipment measuring instruments consumer electronic products amusement equipment etc Those customers intending to use a product in an application requiring extreme quality and reli
18. ability for example in a highly specific application where the failure or misoperation of the product could result in human injury or death aircraft spacevehicle nuclear reactor control system traffic control system automotive and transportation equipment combustion equipment safety devices life support system etc should first contact us We are making our continuous effort to improve the quality and reliability of our products but semiconductor products are likely to fail with certain probability In order prevent any injury to persons or damages to property resulting from such failure customers should be careful enough to incorporate safety measures in their design such as redundancy feature fire containment feature and fail safe feature We do not assume any liability or responsibility for any loss or damage arising from misuse or inappropriate use of the products Anti radiation design is not implemented in the products described in this application manual Please contact Ricoh sales representatives should you have any questions or comments concerning the prod ucts or the technical information June 1995 RHSRH SERIES APPLICATION MANUAL OUTLINE 1 FEATURES 1 APPLICATIONS 1 BLOCK DIAGRAM 2 SELECTION GUIDE 2 PIN CONFIGURATION Re HM 6 3 PIN DESCRIPTION nn 3 ABSOLUTE MAXIMUM RATINGS 8
19. d VouT 0 gt 2V Symbol Item Conditions M Y X Unit Note 5 ES ExT rolad nS EXT H Output Current Vexr Vouroav l 15 EXT T Output Current e l 1 Oscillator Maximum Duty Maxdty Vexr H side 70 Cvcle tstart Soft Start Time Time required for the rising 0 2 of VOUT up to 3V Unless otherwise provided VIN 1 8V Vss 0V IouT 10mA Topt 25 C and use External Circuit of Typical Application FIG 2 RH5RH502B Vour 5 0V N 5 E vw TA Ea EN EH 0 7 EXT no oad VOT EXT H Output Current 2 e EE Oscillator Maximum Duty Maxdty Vexr H side Cycle tart Soft Start Time Time required for the rising of VOUT up to Unless otherwise provided VIN 3V Vss 0V IOUT 10mA Topt 25 C and use External Circuit of Typical Application FIG 2 fl Note 1 referto page 5 Note 1 RICOH RH5RH e RH5RH303B Vour 3 0V eee ee savaa fos oo v saevae on fr me Supplv Current 1 To be measured at OUT pin To be measured at OUT pin VIN 3 5V Lx Switching Current 0 4 TEN B on xr EXT EP Output Current VEEVO OAV Output Current VEXT 0 4V 1 5 1 H Levell Vour gt 1 5V VouT 04 V VCEL1 CE L Level 1 gt 1 5
20. e Output Current FIG 8 The Starter Circuit is necessary for all above circuits 1 for Step up Circuit 2 Step down and Step up Step down Circuit VIN side VouT side Starter Circuit ZDst ZDst 2 5V lt ZDst lt Designation of Output Voltage Rst Input Bias Current of ZDst and Tr several kQ to several hundreds kQ RICOH 27 RH5RH PACKAGE DIMENSIONS Unit mm SOT 89 SOT 89 5 4 50 1 1 5 0 1 0 4 0 1 4 25MAX 0 5 0 3 e E 14 0 4 H il LLI 1 5 0 1 1 5 0 1 0 42 l 042 E T 01 t 04 i 04 1 5 0 1 1 540 1 TAPING SPECIFICATIONS unit mm SOT 89 0 3 0 1 12 0 3 2 5 SOT 89 5 0 3 0 1 0 0 2 5MAX User Direction of Feed RICON 28 RH5RH APPLICATION HINTS When using these ICs be sure to take care of the following points Set external components as close as possible to the IC and minimize the connection between the components and the IC In particular when an external component is connected to OUT Pin make minimum connection with the capacitor Make sufficient grounding A large current flows through Vss Pin bv switching When the impedance of the Vss connection is high the potential within the IC is varied by the switching current This may result in unstable operation of the IC Use capacitor with a capacity of 10uF or
21. he case of a Schottky type diode be taken into consideration RIGO RH5RH TYPICAL CHARACTERISTICS 1 Output Voltage vs Output Current RH5RH301A RH5RH301A L 270uH 3 1 3 1 S 30 lt 30 5 5 2 29 2 29 9 S 28 8 28 S 2 27 m 2 7 8 8 1 5V 3 26 gt 26 2 Vin 1 0V 9 Vin 1 0V 2 0V 2 5 2 5 l 0 10 20 30 40 50 60 Output Current lour mA Output Current lour mA T RH5RH501A L 120uH RH5RH501A L 270uH Output Voltage Vour V Output Voltage Vour V 0 50 100 150 70 50 100 150 Output Current lour mA Output Current lour mA RH5RH302B RH5RH502B 28 3 1 H 5 2 cep 3 0V 4 0 gt 15 2 0 2 5V 30 3 gt gt 9 2 8 Vin 0 9V o Vin 1 5V 2 8 0 200 400 600 0 500 1000 Output Current lout mA Output Current louT mA RICOH 13 14 RH5RH 2 Efficiencv vs Output Current Efficiency Efficiency Efficiency 96 RH5RH301A RH5RH301A 7120 90 H L 270uH 80 90 lt 80 70 1 5V 2 70 5 60 RI 60 Vin 1 0V Vin 1 0V 1 5V 50 50 40 40 0 10 20 30 0 10 20 30 40 Output Current lout mA Output Current lour mA RH5RH501A 1 L 120uH 100 90 90 80 80 70 5 70 59 Vin 1 0V E 99
22. he inductor are the same as those when LxTr is ON and also when LxTr is OFF The difference between ILmax and ILmin which is represented by AI is Al ILmax ILmin VIN ton L VouT VIN topen L PUEDES Equation 1 wherein T 1 fosc ton toff duty ton T 100 ton fosc 100 topenstoff In Equation 1 VIN ton L and VoUT VIN topen L are respectively show the change in the current at ON and the change in the current at OFF 10 RICOH RH5RH When the output current IOUT is relatively small topen lt toff as illustrated in the above diagram In this case the energy charged in the inductor during the time period of ton is discharged in its entirely during the time peri od of toff so that ILmin becomes zero ILmin 0 When IOUT is gradually increased topen eventually becomes equal to toff topen toff and when IOUT is further increased ILmin becomes larger than zero ILmin gt 0 The former mode is referred to as the discontinuous mode and the latter mode is referred to as the continuous mode In the continuous mode when Equation 1 is solved for ton and the solution is tonc tonc T 1 VIN VOUT Equation 2 When ton lt tonc the mode is the discontinuous mode and when ton tonc the mode is the continuous mode Output Current in Discontinuous Mode In the discontinuous mode when LxTr is on the energy PON charged in the inductor is provided by Equation 3 as follows
23. ion circuit resistors for voltage detection a soft start cir cuit and an Lx switch protection circuit A low ripple high efficiency step up DC DC converter can be constructed of this RHSRHXxX1A IC with only three external components that is an inductor a diode and a capacitor These RH5RHXX 1A X X 2B XX3B ICs can achieve ultra low supply current no load TYP 15 by a new ly developed PWM control circuit equivalent to the low supply current of a VFM chopper Step up DC DC con verter Furthermore these ICs can hold down the supply current to TYP 2 by stopping the operation of the oscil lator when the input voltage gt the output voltage set value the dropout voltage by the diode and the inductor These RH5RHXX LA XX2B XX3B Series ICs are recommendable to the user who desires low ripple PWM DC DC converter but cannot adopt a conventional PWM DC DC converter because of its too large supply current The RH5RHXX2B XX3B Series ICs use the same chip as that employed in the RH5RHXX1A IC and are pro vided with a drive pin EXT for an external transistor Because of the use of the drive pin EXT an external transistor with a low saturation voltage can be used so that a large current can be caused to flow through the inductor and accordingly a large output current can be obtained Therefore these RH5RHxx2B xX3B Series ICs are recommendable to the user who need a current as large as several tens mA to several hundreds mA The R
24. layed by an internal phase compensation circuit in order to prevent the oscillation because of such setting of the transient response characteristics take care of the occurrence of the overshoot and or undershoot of the output voltage The internal phase compensation circuit is designed with the avoidance of the problem of the occurrence of the oscillation fully taken into consideration However there may be the case the oscillation takes place depending upon the conditions for the attachment of external components In particular take the utmost care when an inductor with a large inductance is used The performance of power source circuits using these ICs largely depends upon the peripheral circuits Take the utmost care in the selection of the peripheral circuits In particular design the peripheral circuits in such a manner that the values such as voltage current and power of each component PCB patterns and the IC do not exceed their respective rated values RIGO 29 n RICON RICOH COMPANY LTD ELECTRONIC DEVICES DIVISION HEADQUARTERS 13 1 Himemuro cho Ikeda City Osaka 563 8501 JAPAN Phone 81 727 53 1111 Fax 81 727 53 6011 YOKOHAMA OFFICE International Sales 3 2 3 Shin Yokohama Kohoku ku Yokohama City Kanagawa 222 8530 JAPAN Phone 81 45 477 1697 Fax 81 45 477 1694 1695 http www ricoh co jp LSI english RICOH CORPORATION ELECTRONIC DEVICES DIVISION SAN JOSE OFFICE 3001 Orchard Parkwav
25. more and with good high frequency characteristics such as tanta lum capacitor We recommend the use of a capacitor with a resistance to the voltage being at least three times the output set voltage This is because there may be the case where a spike shaped high voltage is gen erated by the inductor when Lx transistor is turned OFF Take the utmost care when choosing a inductor Namely choose such an inductor that has sufficiently small d c resistance and large allowable current and hardly reaches magnetic saturation When the inductance value of the inductor is small there may be the case where ILX exceeds the absolute maximum ratings at the maximum load Use an inductor with an appropriate inductance Use a diode of a Schottky type with high switching speed and also take care of the rated current These ICs are provided with a soft start circuit However there may be the case where the overshoot of the out put voltage takes place depending upon the peripheral circuits employed and the input output condi tions In particular when the input voltage is increased slowly the occurrence of the overshoot of the output voltage becomes conspicuous Therefore in the case where the overshoot becomes a problem take a counter measure against this problem for example by clamping the output OUT Pin by use of a Zener diode The transient response characteristics corresponding to the variations in the input and output are set so as to be slightly de
26. ms Time t ms RICOH 22 19 Distribution of Output Voltage 2 2 2 2 2 2 2 2 2 RH5RH501A 2 2 Por 2 Output Voltage Vour V BB B Bogoogoooooo Oo CO OO COCO COCO COD O OCO O ae gt gt gt gt gt 2 OO DO 34555 N O ON 4 0 OTO gt 0 00 T OOO 20 Distribution of Oscillator Frequencv 10 15 20 Distribution RH5RH501A 25 30 Oscillator Frequency fosc kHz ti e 10 15 Distribution 96 RICON 20 RH5RH 35 25 RH5RH TYPICAL APPLICATIONS e RH5RHXX1A Inductor VOUT Capacitor Components Inductor L 120uH Sumida Electric Co Ltd Diode D MA721 Matsushita Electronics Corporation Schottkv Tvpe Capacitor CL 22uF Tantalum Type FIG 1 RHSRHXX2B Inductor Diode NIL a VIN Capacitor TIT 777 Components Inductor L 28uH Troidal Core Diode D HRP22 Hitachi Schottkv Tvpe Capacitor CL 100 Tantalum Type Transistor Tr 2SD1628G Base Resistor Rb 3000 Base Capacitor Cb 0 01pF FIG 2 RICOH 23 RH5RH e RH5RHxX3B VIN 77 Capacitor TIT TIT Components I
27. nductor L 120uH Sumida Electric Co Ltd Diode D MA721 Matsushita Electronics Corporation Schottky Capacitor CL 22uF Tantalum Type FIG 3 Inductor Capacitor TIT Components Inductor L 28uH Troidal Core Diode D HRP22 Hitachi Schottkv Tvpe Capacitor CL 100 Tantalum Transistor Tr 2SD1628G Base Resistor Rb 3000 Base Capacitor Cb 0 01pF FIG 4 24 RICOH pin Drive Circuit Inductor VIN Diode gt RH5RHXx3B z Pull u resistor Capacitor FIG 5 RICOH RH5RH 25 RH5RH APPLICATION CIRCUITS 12V Step up Circuit Inductor Vana Diode Vout kd RH5RH502B VIN Capacitor Tr 777 777 Starter Circuit Note When the Output Current is small or the Output Voltage is unstable use the Rzd for flowing the bias current through the Zener diode ZD FIG 6 Step down Circuit Inductor PNP Tr 00 N Diode 5 Capacitor Starter Circuit Note When the Lx pin Voltage is over the rating at the time PNP Tr is OFF use a RH5RHxX2B and drive the PNP Tr by the external NPN Tr FIG 7 26 RICOH RH5RH Step up Step down Circuit with Flyback Diode Vout Trance1 1 gt 42 RHSRHXx1A ZZ Capacitor Starter Circuit Note Use a RHSRHXX2B depend on th
28. ply Current 2 excluding Switching Current VIN 5 5V Hx Lx Switching Current 0 4 ILXleak Lx Leakage Current VLX 6V VIN 5 5V Oscillator Frequency Oscillator Maximum Duty l Maxdtv on VLX side Cycle Efficiency tstart Soft Start Time Time required for the rising Notel of VOUT up to 5V VLX Voltage Limit Lx Switch ON E Unless otherwise provided VIN 3V Vss 0V IouT 10mA Topt 25 C and use External Circuit of Typical Application FIG 1 Note 1 Soft Start Circuit is operated in the following sequence 1 VIN is applied 2 The voltage Vref of the reference voltage unit is maintained at OV for about 200us after the application of VIN 3 The output of Error Amp is raised to H level during the maintenance of the voltage Vref of the reference voltage unit 4 After the rise of Vref the output of Internal Error Amp is gradually decreased to an appropriate value by the function of Internal Phase Compensation Circuit and the Output Voltage is gradually increased in accordance with the gradual decrease of the output of Internal Error Amp Note 2 is gradually increased after Lx Switch is turned ON In accordance with the increase of ILx is also increased When VLx reaches Lx Switch is turned OFF by an Lx Switch Protection Circuit RICON RH5RH e RH5RH302B VOUT 3 0V TYP MA 0 Oscillator Start up Voltage EXT no loa
29. utput Current lour mA lour 10mA Vin 3V L 120uH RH5RH501A 5 2 5 1 5 0 4 9 4 8 4 7 40 20 0 20 40 60 80 100 Temperature lout 10mA Vin 3V L 284uH RH5RH502B 5 2 5 1 5 0 4 9 4 8 4 7 40 20 0 20 40 60 80 100 Temperature RICOH 17 RH5RH 7 Start up Voltage vs Temperature Start up Voltage Vstart V RH5RH501A 1 2 1 0 0 8 0 6 0 4 0 2 20 0 20 40 60 80 Temperature 9 Supply Current 1 vs Temperature Supply Current 1 Ippi uA RH5RH501A 100 80 60 40 20 20 0 20 40 60 80 Temperature 11 Lx Switching Current vs Temperature Lx Switching Current ILx mA RH5RH501A 150 125 100 75 50 25 20 0 20 40 60 80 Temperature 8 Hold on Voltage vs Temperature Hold on Voltage Vhold V RH5RH501A 1 0 0 8 0 6 0 4 0 2 20 0 20 40 60 80 Temperature 10 Supplv Current 2 vs Temperature Supply Current 2 Ipp2 uA RH5RH501A 5 4 3 2 1 0 40 20 0 20 40 60 80 Temperature 12 Lx Leakage Current vs Temperature Lx Leakage Current ILXieak RH5RH501A 1 0 0 8 0 6 0 4 0 2 20 0 20 40 60 80 Temperature
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