Hitachi RAS-50YH4 Service Manual page 73

8. HIC and Peripheral Circuits
Fig. 8-1 shows the micro computer and its peripheral circuits, Table 8-1, the basic operations of each
●
circuit block, and Fig. 8-2, the system configuration.
Detection Resistor
N1
L
N
Table 8-1
Circuit block
Peak current
cutoff circuit
Set value circuit
Voltage amplifier
circuit
Reset circuit
Trip signal
synthesis circuit
R24
DC Current
R41
9
0V 0V
Is
CT1
D104 R005
58
+
0V
0V 0V
62
+
0V
Fig. 8-1 Microcomputer and Peripheral Circuits
Detects DC current flowing power module and during overcurrent (instantaneous
value) flows, stops upper/lower arm drive circuits and also produces lp signal by
which drive signal output is stopped.
Compares voltage detected, amplified and input to HIC with set voltage value in
microcomputer, and controls overload when set value exceeds input voltage.
Voltage-amplifies DC current level detected by the detection resistor and inputs
this to microcomputer. Internal or external overload is judged in microcomputer.
Produces reset voltage.
Modulates chopper signal to drive signal and stops according to presence/ab-
sence of lp signal or reset signal.
SPM2 – HIC
IC1
OC
9
F
8
P2
20
10 9
CN14 CN13
1 2
+
C205
0V
38 39
6
–
7
R245
+
R248
+ 5
IC4
R222
R221
0V
12V
0V
2
–
1
+
JW10
3
IC5
R288
0V 0V 0V 0V
Basic operation
– 83 –
Direct Current
DC260-380V
SPM2
1
MAIN P.W.B
5
HIC
37
59
Vd
0V 0V
17
Ip
5V
60 Id
0V IC1
5V
MICROCOMPUTER
61 Is
C218
0V
48 RESET
R252
0V