Abstract: A constant-current control circuit for a stepped motor of unipolar excitation. First and second switch devices are connected to phase and complementary phase inputs of the motor, respectively, and are responsive to a control signal. A sensor is connected to the switch devices to provide a sensor signal indicative of the current flowing in the phase or complementary phase input, and a generator means is included to provide a constant reference signal. Regulating and comparison means is included to compare the sensor signal and the reference signal, and regulate the current conducted by the switch devices in response thereto.