Full-bridge motor driver

Paul Boughton

Allegro Microsystems is announcing a new DMOS full-bridge motor driver to complement the company’s existing parallel-input dc motor driver family.

Designed for pulse width modulated (PWM) control of dc motors, the A3950 is capable of peak output currents to ±2.8A, and operating voltages to 36V. The A3950 is targeted at the office automation, industrial, and medical markets.

Phase and enable input terminals are provided for use in controlling the speed and the direction of rotation and torque of a dc motor with externally applied PWM control signals.

Internal synchronous rectification control circuitry reduces power dissipation, says the company, by switching on appropriate DMOS outputs to effectively short out the body diodes during PWM operation.

This internal control technique can reduce output power dissipation by 10 to 30percent in most applications.

The A3950 has an over-current protection (OCP) feature that prevents IC damage during motor lead short-to-supply and ground conditions.

Other internal circuit protection features include thermal shutdown with hysteresis, undervoltage lockout of the motor supply and charge pump output, and crossover-current protection.

A diagnostic, open drain output is provided to indicate fault conditions. 

For more information, visit www.allegromicro.com

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