FUJITSU MB3878 - Manual (Page 4)

MB3878
4
■ ■ ■ ■ BLOCK DIAGRAM
+
−
−
+
8
10
13
12
9
+
−
−
+
4
2
24
1
3
Ч
25
Ч 25
+
+
+
−
5
20
21
19
−
+
+
+
−
11
16
22
17 6 23
14
18
<Current Amp.1> <Error
Amp.1>
7
VREF
<Current Amp.2> <Error
Amp.2>
VREF
<Error
Amp.3> VREF
VREF
VREF
5.0 V
4.2 V
1
µ
A
15
<SOFT>
2.5 V
1.5 V
<OUT>
<UVLO>
<OSC>
Bias
Voltage
<VH>
<REF> <CTL>
<PWM Comp.>
Drive
VCC
(V
CC
− 5 V)
(VCC UVLO)
VCC
VCC
VCC
CTL
215 k
Ω
35 k Ω
0.91 V
(0.77 V)
VREF
UVLO
bias
−
INC2
OUTD
FB2
OUTC2
VREF
−
INE2
+
INE2
+
INE1
FB1
OUTC1
− INE1
−
INC1
+ INC2
GND
CS
VCC (O)
OUT
VH
RT
−
INE3
FB3
+
INC1
(45 pF)