To control a plurality of power supplies for a DC motor by one controller without using a sample and hold circuit for each power supply.
Outputs of a multiplexer circuit 8 arranged between a plurality of switching power supplies 3 for driving a DC motor and one microcomputer 1 are connected to control inputs for the switching power supplies 3 via an integrating capacitor C. The microcomputer 1 outputs a control signal for setting an output voltage to the power supplies 3 by switching the multiplexer circuit 8. In that case, the switching power supplies 3 determine the amplitude and duty ratio of the pulse train of the control signal to be output so as to attain a predetermined control voltage so that one microcomputer 1 can control the plurality of power supplies 3 for a DC motor without using the sample and hold circuit.
Takayoshi Tagawa
Higashio Masahiro
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