DC/DCコンバータ設計セミナー - ROHM

1 C ROHM Co.,Ltd. All Rights Reserved DC/DC c ROHM Co.,Ltd. All Rights Reserved 1. 1 / 2. ( ) / c ROHM Co.,Ltd. All Rights Reserved 2 1. c ROHM Co.,Ltd. All Rights Reserved 3 VREF 2 VOUT VIN VO VREF R2 R1 =VREF VREF = VO = R2 = 10k 100 A R1 23k 100 A 33k = IN OUT FB FB VIN VO Tr c ROHM Co.

2 ,Ltd. All Rights Reserved 4 LDO Low Drop Out LDO CMOS / LDO / LDO HTSOP-J8 HSON8 c ROHM Co.,Ltd. All Rights Reserved NPN / PNP Pch / nch mosfet 5 NPN 78xx/79xx 1A NPN LDO 5A PNP LDO LDO Pch/ nch mosfet VIN VO VREF R2 R1 =VREF NPN 3V NPN LDO 1V 2V PNP LDO MOSFET LDO c ROHM Co.

3 ,Ltd. All Rights Reserved 6 AV RF c ROHM Co.,Ltd. All Rights Reserved Vref 7 Typ Min Max c ROHM Co.,Ltd. All Rights Reserved VO Tj MAX VO IO Ta 8 VREF VIN MAX VDROPOUT Tj MAX VO IO Ta VREF % VO VREF VIN MAX VO VDROPOUT VREF c ROHM Co.

4 ,Ltd. All Rights Reserved Tj MAX VIN VO Ta 9 LDO IO IO Ta VIN MAX VO VDROPOUT VREF c ROHM Co.,Ltd. All Rights Reserved CPU IC 10 c ROHM Co.,Ltd. All Rights Reserved 10 100 1k 10k 100k 1M dB PSRR - 11 c ROHM Co.

5 ,Ltd. All Rights Reserved 12 VIN VO VDROPOUT VIN VO IIN IO c ROHM Co.,Ltd. All Rights Reserved 13 / ( ) 2. c ROHM Co.,Ltd. All Rights Reserved 14 DC/DC / AC/DC AC DC PWM PFM c ROHM Co.

6 ,Ltd. All Rights Reserved 15 / VO/VIN 95% W c ROHM Co.,Ltd. All Rights Reserved 16 75% 25% 50% 50% 50% 25% VIN % VO S1 ON S2 OFF L1 VIN S1 OFF S2 ON L1 GND VIN (DC) VIN/GND C1 DC VINVOS1S2L1C1 c ROHM Co.,Ltd. All Rights Reserved VIN D1 C1 L1 S1 VO 17 S1 D1 S2 S1 ON OFF IO IO IO 0 0 0 VIN VIN 0 0 0 0 0 VIN VOUT 0 IO IIN 0 S1 VIN C1 L1 D1 SW OFF SW ON SW OFF Diode ON Diode OFF Diode ON c ROHM Co.

7 ,Ltd. All Rights Reserved 18 c ROHM Co.,Ltd. All Rights Reserved 19 3 VIN VOUT VIN VOUT VIN VOUT VIN VOUT c ROHM Co.,Ltd. All Rights Reserved 20 ( ) L OUT C Vin IN Vout Vout Vin SW1 SW2 ON OFF ON OFF SW1 SW2 SW1 ON c ROHM Co.

8 ,Ltd. All Rights Reserved 21 Toff Toff Toff Ton Ton Ton SW Im Iout Id Iout FB OSC Vin M1 Di Id L Vout Im SW OSC ERROR AMP INV PWM COMPARATOR DRV FB R1 R2 ADJ FB ADJ FB ON Iout IL ton toff T IL IL R1 R Vin c ROHM Co.,Ltd. All Rights Reserved L1-N / / V-1135I(Q1-D) / A-20246 Time/uSecs1uSecs/div194195196197198199I( D1-anode) / A-20246C110uL1D1V1Q1V2R1I122 FET ON Vout SW FET Di c ROHM Co.,Ltd. All Rights Reserved C110uL1D1V1Q1V2R1I123 DUTY DUTY 20 DUTY 80 L1-N / / V-1135I(Q1-D) / A-113 Time/uSecs1uSecs/div193194195196197198I( D1-anode) / A-113R1-P / mV740780820860Q1-S / V-1135I(Q1-D) / A-113 Time/uSecs1uSecs/div194195196197198I(D1- anode) / A-113 Vout SW FET Di Vout SW FET Di c ROHM Co.

9 ,Ltd. All Rights Reserved 24 ( ) OUT C Vin IN Vout Vin Vout SW SWON L SW OFF c ROHM Co.,Ltd. All Rights Reserved 25 Ton Ton Ton Toff Toff Toff SW Im Iout Id Iout FB OSC Iout IL ton toff T Vin M1 Di L Vout SW OSC ERROR AMP INV PWM COMPARATOR DRV FB IL Im Id ADJ FB FB ON IL R1 R2 ADJ c ROHM Co.,Ltd. All Rights Reserved D1-cathode / / V-048I(D1-anode) / A036 Time/mSecs500 3 5 VC110uL1D1V1Q1V21R11I1 FET ON Vout SW FET Di c ROHM Co.

10 ,Ltd. All Rights Reserved 27 D1-cathode / / V1357I(Q1-D) / A-0123 Time/mSecs1 (D1-anode) / A-01234D1-cathode / / V-01020I(Q1-D) / A-0481216 Time/mSecs1 (D1-anode) / A-0481216 DUTY DUTY 20 DUTY 80 VC110uL1D1V1Q1V21R11I1 Vout SW FET Di Vout SW FET Di c ROHM Co.,Ltd. All Rights Reserved 28 ( ) OUT C Vin IN Vout Vin Vout SWON SW OFF SW1 L c ROHM Co.,Ltd. All Rights Reserved 29 Ton Toff SW Im Iout Id Iout FB OSC Vin M1 Di L Vout SW OSC ERROR AMP INV PWM COMPARATOR DRV FB IL Im Id ADJ FB FB ON IL R2 R1 ADJ Toff Ton Toff Ton Toff IL ton toff T Iout c ROHM Co.