Hitachi RAM-35QH5, Service Manual

Page: 48 / 78

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7. Peripheral circuits of microcomputer
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Fig. 7-1 shows the microcomputer and its peripheral circuits.
Table 7-1, the basic operations of each circuit block and Fig. 7-2, the system configuration.
Table 7-1
Circuit block Basic operation
Peak current
cutoff circuit
Overload external
judgment circuit
Voltage amplifier
circuit
Reset circuit
This circuit detects DC current flowing to power module: When over-current
(instantaneous value) flows, it stops upper and lower arm drive circuits and also
produces lp signal to stop microcomputer.
This circuit detects DC current flowing to power module and produces signal to
notify microcomputer of overload status.
This circuit voltage-amplifies DC current level detected by detection resistor and
sends it to microcomputer. In addition, setting of internal/external overload
judgment is performed.
This circuit produces reset voltage.
Fig. 7-1 Peripheral circuit of microcomputer (AX-6M01)