Circuit Description - Kenwood KAC-PS650D Service Manual

2
D151
R129
D153
1 receives mute signal from MUTE-2 terminal of u-COM,
and bias voltage of is short-circuited, and driver transistors
2
and final transistors on X08- get in condition of non-operation,
and shock noise is prevented.
Triangular Wave Former Circuit
11
4
R365
12
5
820
6
IC11
D305
(1/2)
D309
R351 C331 R354
2.2K 10u16 1K
D5
Q13
MUTE
Dead Time Oscillation Circuit
5V
R368
4.7K
D310
IC12
(4/4)
14
12 10
11 8
R369
13 9
7
IC12
4.7K
(3/4)
D311
KAC-PS650D/X650D

CIRCUIT DESCRIPTION

Shock Noise Prevention Circuit
Q428
33
Q159
Q429
PWM Wave Former
R362
3K
C357
R366 8
2
0.01
1
3
4.7K
4
D306
IC10
(1/2)
IC10 (2/2)
4
5
R358
7
6
4.7K
R356 C354
1K 47P
R357
680K
R376
33K
OUTPUT
14
2 5
3 6
D312
1
4
IC12 IC13
(1/4) (2/4)
IC12 IC13
(2/4) (1/4)
5 1
6 3
D313
4 2
7
+B
1
R454
R451
10K
Q426
10K
Q427
R453
10K
D435
R517
10K
B
3 : Triangular wave form
3
: Analogue signal
4
5 : PWM wave form
This circuit creates PWM wave form
after comparing triangular wave form
and analogue signal
5
3
9
10
4
7
0
5
0
After PWM wave form
and down-gate wave forms, this circuit makes
off-timing so that up-gate and down-gate wave
forms do not turn on at same time.
R370
1K
UP-GATE
UP
R371
DEAD TIME
1K
DOWN-GATE
D431
u-COM
"MUTE-2"
5
3
4 .
is divided into up-gate
5
DOWN UP
3