MB3875 Datasheet, PDF (5/27 Pages) Fujitsu Component Limited. – DC/DC Converter IC for Charging

MB3875/MB3877
s BLOCK DIAGRAM
−INE1
11
OUTC1
10
+INC1
<Current Amp.1>
13
+
−INC1
12
× 25
−
+INE1
8
FB1
9
−INE2 ₆
OUTC2 ₄
+INC2 ^{<Current Amp.2>}
24
+
−INC2
1
× 25
−
+INE2
7
<Error
Amp.1>
VREF
−
+
<Error
Amp.2>
VREF
−
+
FB2
3
<PWM
Comp.>
+++−
<OUT>
Drive
VCC (O)
21
OUT
20
VCC
Bias voltage
block
VH
19
<VH>
(VCC − 5 V)
IN3
2
−INE3
16
R1
∗
R2
50 kΩ
FB3
15
<SOFT>
VREF
1 µA
CS
22
<Error
Amp.3>
VREF
−
+
+
VREF
(4.2 V)
<UVLO>
VCC
(VCC UVLO) 215 kΩ
35 kΩ
0.91 V
(0.77 V)
VREF
ULVO
2.5 V
1.5 V
<OSC>
(45 pF)
VCC
bias
<REF> <CTL>
17
5
23
RT VREF
GND
∗ : MB3875 100 kΩ
MB3877 150 kΩ
VCC
18
CTL
14
5