???????(POL)

1
?????????

• ??????
• ????,?????????
• ???????(POL)
• ??
• ? ???,???????,????
• ? ???
• ? ????????????PWM?????????

2
?????????

• ??????
• ? ????
• ? ???????PWM??IC
• ? ??????? PWM??IC
• ? ??????? PWM??IC
• ? ?????
• ? Buck???Buck????? PWM??IC

3
?????????

• 2?????

?????? ??????
??? ?? ??,??????????
?? ? ??
???? ??,??,??? ?
????? ????,??????? ???,??????
??????? ?,?????????? ??,??????????
??? ? ??
???? ? ??
?? ? ??
4
Step-Down/Buck?????
??Buck??? 1 ?????????(???gt?????????????) 2 ???
L
Vin
Vo
R
C
5
Step-Down/Buck?????
????????
6
CCM??????

• ???????
• IAVE gt ½ IRipple
• ?????????????
• ??????0
• PWM??,????????
• ?????????

L
rc
Vin
Vo
d
R
C
PWM
????????,??????,???????,?????????????????????????
7
DCM???????

• ???????
• IAVE lt ½ IRipple
• ?????(??)?????0
• ?????0??,????????????,???????0
• ????????????
• ??????????????

L
rc
???????
Vo
d
R
Vin
C
PWM
8
?????????

• ?????????????
• Forced Continuous Mode
• Pulse Skip Mode(??DCM)
• Burst Mode

9
Forced Continuous Mode

• ?????????????????????????
• ?????????????????????????

• ????????????
• ?????????????????????,??????
• ????????????????

10
Pulse Skipping Mode

• ???????????????,????????????
• ??????????????????????????????????
• ?????????????????????????
• ????????????????
• ???????????Iq?????
• ??????????,?????????????

• ????????????,?????????????

11
Burst Mode Operation

• ?????????,???????????
• ???????Iq????
• ?disable???,?????????????????
• ????
• ?????????????????????????????

?????????

• ?????????????????????????
• ????????????????????
• ????????,??????????????????????

12
Burst Mode vs. Pulse Skip mode (Vout and IL)
Burst mode
Pulse skip mode

• ?????????????
• ?????????

• ????????????
• ????????

13
????????

• Burst Mode?????????,??? Pulse Skip Mode,Forced
  Continuous Mode??????

• Forced Continuous Mode?????????,?? Pulse Skip
  Mode, Burst Mode???????

14
??
Forced Continuous Pulse Skipping Burst
???? Okay Good Best
????? Best Good Okay
?? Best Good Okay
15
??????BUCK???
L
rc
Vo
d
R
Vin
C
PWM
R2
d
VFB
slope
Comp.
R1
dkVc
vc
Comparator
Vref
????????
???????A(s)
16
??????BUCK???

• ??
• ????????????
• ??
• ????????????,????????
• ?????????ESR???,??????????
• ????/?????????
• ???????????????,????????????

17
??????BUCK???
Rsense
L
rc
vo
Vo
d
R
Ki
Vin
C
PWM
d
R2
slope comp
C2
iL feedback
Kref(s)
EAIN
gm
R1
C1
veain
igm
Comparator
ITH
vc
Rth
Ro

• ???????????
• ??????????
• ????????
• ????????????????C

Cthp
Vref
Cth
Error Op-Amp
Compensation Network
18
??????BUCK???

• ??
• ??/??????
• ??????????
• ????????/?????????????????
• ??/???????
• ????
• ??
• ???????????,???????

19

• ???????????

?????????????????IC VC??????RC??,?????????????????
??????????????,??????????????? ?
??????????????????????????????????????????????????
??,?????????????????????????,?????????????????????
???,?????????????,????????????????????????????????
??????????
20
????????BUCK???
L
rc
vo
Vo
d
R
C
PWM
d
iL x Rds(on)
R2
C1
Kref(s)
EAIN
gm
R1
veain
igm
Comparator
ITH
vIth
Rth
Ro
Cthp
Vref
Cth
Error Op-Amp
Compensation Network
21
????????BUCK???
iL
Io
iL X Rds(on)
VIth
VIth iL X Rds(on)
????????
????????
??????
??????????????VO
22
?????????????
iL
Io
??????????
??????????
?????? ???0A??5A
?????? ???0A??5A
23

• ??
• ????????
• ?????????
• ???????
• ??????????
• ??
• ????
• ????????????
• ?????????
• ??PCB??????

???????BUCK??
???????????????? (1)??, ???????????????. (2)
????????