MB3785A Datasheet, PDF (5/29 Pages) Fujitsu Component Limited. – Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)

MB3785A
s BLOCK DIAGRAM
+IN1 (E) 7
–IN1 (E) 6
FB1 5
–IN1 (C) 8
DTC1 ⁴
CH 1
Error Amp 1
+
–
+
VREF
+
Comparator 1
DTC
–
2V
–
Comparator 1
–
–
+
VREF
PWM comparator 1
OFF Current
Setting
2.5 V
+IN2 (E) 12
–IN2 (E) 11
FB2 10
–IN2 (C) 13
DTC2 9
CH 2
Error Amp 2
+
–
VREF
Comparator 2
+
–
+
–
DTC ^{2 V}
Comparator 2
–
–
+
VREF
PWM comparator 2
OFF Current
Setting
2.5 V
+IN3 (E) 25
–IN3 (E) 26
FB3 27
–IN3 (C) ²⁴
DTC3 28
CH 3
Error Amp 3
+
–
Comparator 3
+
0.6 V
–
PWM comparator 3
+
+
–
100 Ω
OFF Current
Setting
2.5 V
CH 4
Error Amp 4
+IN4 (E) 30
+
–IN4 (E) 31
FB4 32
–IN4 (C) 29
–
Comparator 4
+
0.6 V
–
DTC4 33
SCP
Comparator
––––+
2.1 V
SCP
23
1 µA
PWM comparator 4
+
+
–
100 Ω
OFF Current
Setting
2.5 V
–
–
DTC
+
Comparator 3
VREF
1.2 V
–1.9 V
–1.3 V
SR
SR Latch
Under Voltage
Lock-out
Protection Circuit
Triangular-Wave
Oscillator Circuit
Ref. Power Supply
Vol. Circuit & Channel
Circuit
Control
14
OSCIN
15 16
2.5 V
17
19
RT CT
VREF
42
GND
Ca1
1
48 ^Cb1
45 VCC2
46 OUT1
47
VE1
3
2 ^Ca2
Cb2
44 OUT2
43
VE2
34
33 ^Ca3
Cb3
40 OUT3
41
VE3
Ca4
36
37
Cb4
39 OUT4
38
VE4
21 CTL2
22 CTL3
18 _VCC1
20 CTL1
OSCOUT
Ceramic Resonator
5