The circuit uses one chopper to chop all currents supplying to the solenoids and to compensate the differences of solenoid characteristics as a whole. The circuit comprises a solenoid and switch circuit (10) having a logic circuit generating the solenoid drive control signal according to the signals input through wires (Wire1-Wiren) and switching devices drived by the control signals, a waveform modulator (30) for modulating signals transmitted through the wires, a current detector (20) for detecting the currents flowing through the solenoids, an adder (40) for adding the output signals of the modulator and the current detector, a divider (50) for dividing the output of the adder by certain value, and a switching circuit (70) for pulling up and down the fire unit according to the output signal of the comparator (60).
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