Harman Kardon DPR 1001, Service Manual

Page: 137 / 165

Features
• 5V
±
1% Reference
• O scillator Sync Term inal
• Internal Soft Start
• D eadtim e Control
• U nder Voltage Lockout
D escription
The K A 3525A is a m onolithic integrated circuit that
includes all of the control circuits necessary for a pulse w idth
m odulating regulator. There are a voltage reference, an error
am plifier, a pulse w idth m odulator, an oscillator, an under
voltage lockout, a soft start circuit, and the output driver in
the chip.
16-D IP
1
Internal B lock D iagram
16
15
12
1
2
9
8
10
5
7
3
6
4
14
11
13
U .V.L.O .
BAN D G AP
R EF 5V
LATC H
S
R
F/F
Q
Q
5K
VC
O U TPU T A
O U TPU T B
O SC ILLATO R
D ISC H AR G E
5K
ER R
AM P
P W M
C O M P
_
+
_
+
C
T
V
R EF
V
C C
G N D
EA(-)
EA(+)
EA O U T
C
(S O FT
STA R T)
SH U T D O W N
SYN C
R
T
O SC
O U TPU T
K A 3525A
137
DPR1001 harman/kardon