The M54670P can drive a stepper motor by the 2-phase bipolar method and also control the coil current. Furthermore, it controls the direction of the coil current with Ph input pins (pins 3 and 30). The coil current value can be selected among four levels (0 to max.) by selecting the combination of three internal comparators by logic input (pins 14, 15, 18 and 19). It also can be continuously controlled with VR pins (pins 2 and 31). By selecting an I input pin among pins 14, 15, 1 8 o r 19, the operation timing, 2-phase excitation, 1-2-phase excitation o r microstep, can be selected. Because two control circuits are built in this IC, a stepper motor can be driven with a single IC by the 2-phase bipolar method.