ON Semiconductor Fairchild PFC SPM, Руководство по конструкции

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PFC SPM
®
Design Guide
© 2005 Rev. 1.0.1-2012 Fairchild Semiconductor – System Engineering Group
11
] [ 470 471
10 300
002 . 0 2 50
6
_
  






GMMAX
sense peak AC
MO
I
R I
R
(Assuming the input current is 50A
RMS
@ V
AC
= 100V
RMS
)
 R
MO
= 470[ Ω ]
R
sense
= 0.002[ Ω ]( small resistance can cause distortions at low level current)
R
AC
& Optocoupler circuit:
Optocuopler: TLP180
RAC
RFF
UCC3818
ISINE
VFF
CL
VCC
Optocoupler
1
2
5
4
RAX
CFF
RL
-
+
Rc1
Rc2
Fig.7 Input AC voltage sensing circuit
R
AX
and R
L
depend on optocoupler :
] [ 64
10 6
2 270
2
3
max _
max _
 






k
I
V
R
LINEAR
RMS
AX

) 2 4 5 . 0 ]( [ 18 18 18 18 W k
     
] [ 18
10 5 . 0
9
3
max _
_
 

 

k
I
V
R
AC
PEAK RL
AC
] [ 390
 
L
R
R
C1
, R
C2
, C
L
, and an op-amp  I
SINE
off-set compensation
C
L
= 1[uF], R
C1
= 0[ Ω ], R
C2
= 150[ Ω ],