KENWOOD KACX621
Manual de Servicio

KAC-PS621/X621
CIRCUIT DESCRIPTION
� Current detection circuit
Amplify and rectify potential differences at two points in the primary-side current circuit and send it to the AD-port of the MPU and obtain data for displaying current value.
1K

MPU AD-PORT OUTPUT

0.01

0.01

VOLTAGE LEVEL DETECTION
13K 1 2 3 8 470 L5

10K 7 4 6 5

D309 IC9 (2/2)

15K
10K

IC9 (1/2)

AMP RECT

� Constant current output circuit
Remove troubles caused by the potential differences between the constant current output and the GND, so that the GND potential differences between the H/U and the AMP is not overlapped in the AMP to H/U communication.

J3
4 3 7 2 6 10 13 H/U-GND 1 5

AD-I

8

Q301 to H/U
47 47 REQC

Q305 from Q307 MPU
10K 10K

12

10u35 +
11

9

Q303 H/U GND CONSTANT CURRENT

AMP GND

� I2C buffer
Using an IC for I2C communication, between-AMP communication is conducted so that there will be no trouble from GND potential differences.
5

to OTHER AMP TRANSMISSON RECEIVE
4.3K 4.3K 270

J4
24 13 270 CLK

D302
SX VCC 2 7

100K

20K 12K 1.8K

IC3
RX SY

3 6 1.8K TX RY GND TY 47

10 11

79
1 8

to MPU TRANSMISSON RECEIVE
1.5K 1.5K

DATA 10u25 10K

D301

BOTH DIRECTION BUFFER

ADJUSTMENT
No. 1 Item IDEL CURRENT VR2 (Rch) check land A, B. Alignment Point VR1 (Lch) Method Connect a DC voltmeter between 2.5mV 2 minutes (X09-577) Align For Note After Power on Fig. PC board

4 5

68

270

7