The UC3717 is an integrated circuit designed to control and drive the current in one winding of a bipolar stepper motor. It has half-step and full-step capability, built-in fast recovery Schottky commutating diodes, wide range of current control 5-1000mA, wide voltage range 10-45V, designed for unregulated motor supply voltage, current levels can be selected in steps or varied continuously, thermal overload protection.