| 摘要 |
PROBLEM TO BE SOLVED: To suitably suppress a current supplied to an electromagnetic device and realize a failsafe function in the form of an electronic circuit, when an operating part in the control circuit for controlling the electromagnetic device having a proportional solenoid part runs away. SOLUTION: A CPU 33 generates command signals for a plurality of respective proportional solenoid valves 30-1 to 30-n, the command signals are selected by a multiplexer 36, supplied to corresponding channels, held in capacitors 40-1 to 40-n as command voltages, amplified by operational amplifiers 41-1 to 41-n, and converted into currents to be supplied to proportional solenoid parts. A runaway detection circuit 11 is provided for detecting a runaway of the CPU 33. When the runaway detection circuit 11 detects the runaway of the CPU 33, a discharge path is formed for preventing a higher voltage in the capacitors 40-1 to 40-n. The discharge path is made up of preferably a diode connected between a reset terminal of the runaway detection circuit and the capacitors.
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