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.