MB3881
s
BLOCK DIAGRAM
• General view
FB1 47
−IN1
46
Error
−
Amp.1
+
+
1.25 V
SCP
Comp.1
−
+
+
PWM
Comp.1-1
+
+
−
PWM
Comp.1-2
+
−
Drive
1-2
CH1
Drive
1-1
58 VCC(O)-1
50 OUT1-1
49 VSS(O)-1
VB1
52 VDD(O)
51 OUT1-2
1.0 V
DTC1 48
FB2 44
−IN2
43
Error
−
Amp.2
+
+
1.25 V
SCP
Comp.2
−
+
+
1.0 V
DTC2 45
PWM
Comp.2-1
+
+
−
PWM
Comp.2-2
+
−
CH2
Drive
2-1
53 OUT2-1
VB2
Drive
2-2
54 OUT2-2
FB3 41
−IN3
40
Error
−
Amp.3
+
+
1.25 V
SCP
Comp.3
−
+
+
1.0 V
DTC3 42
PWM
Comp.3
+
+
−
CH3
Drive
3
56 OUT3
A
FB4 38
−IN4
37
Error
−
Amp.4
+
+
1.25 V
SCP
Comp.4
−
+
+
1.0 V
DTC4 39
PWM
Comp.4
+
+
−
CH4
Drive
4
57 OUT4
55 GND(O)-1
FB5 20
−IN5
21
Error
−
Amp.5
+
+
0.6 V SCP
Comp.5
−
+
PWM
Comp.5
+
+
−
CH5
Drive
5
59 VCC(O)-2
60 OUT5
63 VSS(O)-2
−IN5(C)
23
+IN5
22
DTC5 19
FB6 14
−IN6
15
Error
−
Amp.6
+
+
0.6 V SCP
Comp.6
−
+
PWM
Comp.6
+
+
−
CH6
Drive
6
61 OUT6
B
−IN6(C)
17
+IN6
16
OVP 18
DTC6 13
FB7 10
−IN7
11
Error
−
Amp.7
+
+
+
1.25 V
SCP
Comp.7
−
+
+
+
1.0 V
DTC7 9
PWM
Comp.7
+
+
−
CH7
Drive
7
62 OUT7
+IN7
12
20 kΩ
80 kΩ
FB8 4
−IN8
5
−
+
+IN8
6
−IN8(C)
7
+IN8(C)
8
DTC8 3
−
+
SCP
Comp.8
Error
Amp.8
PWM
Comp.8
−
−
+
CH8
Drive
8
64 OUT8
2 RB8
1 GND(O)-2
C
CTL
1, 3, 4 CS CTL
CTL-2 29
Logic
CTL-3 30
CTL-4 31
Buff
Buff
×0.8
CT1 1.73 V
1.0 V
CT2 1.73 V
1.0 V
CT
0.8 V
0.3 V
CS 32
UVLO
Power
Ref ON/OFF
CTL
2.5 V
24
VREF
25
GND
27 VCC
VB 36
OSC
2V
35
33
34
CT
SCP
28 CTL-1
H : ON (Power/CH1, 3, 4, 8)
L : OFF (Standby mode)
26
CSCP
SYNC RT
(64 pin)
5
FUJITSU [ FUJITSU COMPONENT LIMITED. ]
