-51-
IC Block Diagrams
●
FA7701 <DC-DC control, IC5611>
FA7701
+
–
+
P W M
–
+
E R . A M P
ON/OFF
V R E F
O S C
BIAS
U V L O
5.5V
–
+
–
+
ON/OFF
S.C.DET
0.3V
1.5V
1.5V
–
+
S.C.P
2.2V
OFF
RT
REF
4
FB
IN–
1
2
3
8
7
6
5
CS
VCC
OUT
GND
0.88V
Power Good Signal
VREF
2.2V
●
FA7703 <DC-DC control, IC5631>
9
12
13
16
15
14
11
10
5
4
1
2
3
6
7
8
REG
VCC
CUT1
SEL
1
FB1
IN1-
RE
F
DT
1
RT
OUT
2
GND
FB2
IN2-
IN2+
DT
2
CS
OS
C
Power Good Signal
BIAS
UVL0
BIAS
2.2V
1V
lcs
+
_
_ +
+ +
+
_
+ +
+
_
+
_ _
+
_
1.5V
1.27V
2.0V
ON/OFF
ON/OFF
S.C.P
S.C.DET
Error AMP1
Error AMP2
Pedestal
Vo
ltage
PWM
Comparator1
PWM
Comparator2