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Text excerpt from page 7 (click to view)
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
