The UC3717A is an improved version of the UC3717, used to switch drive the current in one winding of a bipolar stepper motor. The UC3717A has been modified to supply higher winding current, more reliable thermal protection, and improved efficiency by providing integrated bootstrap circuitry to lower recirculation saturation voltages. The UC3717A features LS-TTL compatible logic input, a current sensor, a monostable, a thermal shutdown network, and an H-bridge output stage. Two UC3717As and a few external components form a complete control and drive unit for LS-TTL or micro-processor controlled stepper motor systems.