UC3717A

UC3717A Stepper Motor Drive Circuit FEATURES Full-Step, Half-Step and Micro-Step Capability Bipolar Output Current up to 1A Wide Range of Motor Supply Voltage 10-46V Low Saturation Voltage with Integrated Bootstrap Built-In Fast Recovery Commutating Diodes Current Levels Selected in Steps or Varied Continuously Thermal Protection with Soft Intervention DESCRIPTION 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 diagram shown below presents the building blocks of the UC3717A. Included are an LS-TTL compatible logic input, a current sensor, a monostable, a thermal shutdown network, and an H-bridge output stage. The output stage features built-in fast recovery commutating diodes and integrated bootstrap pull up. Two UC3717As and a few external components form a complete control and drive unit for LS-TTL or micro-processor controlled stepper motor systems. The UC3717A is characterized for operation over the temperature range of 0°C to +70°C. ABSOLUTE MAXIMUM RATINGS (Note 1) Voltage Logic Supply, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V Output Supply, Vm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50V Inp...