Abstract: A solenoid driver applies an actuation current to a solenoid for a predetermined period and a lower holding current thereafter. A switching device pulses the applied current within upper and lower limits to maintain the actuation and holding current amplitudes, the pulses being integrated by solenoid inductance into a substantially steady-state current. A multiprocessing unit determines the amplitudes of solenoid current. A signal representative of desired current amplitudes is compared with a signal representative of measured solenoid current, and a signal representative of the difference therebetween is used to control the switching device. Voltage developed across a resistor in series with the solenoid is input to a differential amplifier having connected to its output a peak detector that mimics the decay rate of current in the solenoid, the signal representative of measured solenoid current being obtained from the peak detector.