Allegro Announces New Digitally Programmable Dual Full-Bridge MOSFET Driver

Allegro Announces New Digitally Programmable Dual Full-Bridge MOSFET Driver

Allegro® MicroSystems, Inc. has announced a new DMOS bipolar stepper and DC motor driver designed to drive one bipolar stepper motor at up to 1.2 A and one DC motor at up to 2.4 A. Capable of drive voltages up to 36 V, Allegro's A3989 includes a fixed off-time current regulator for each of the three full-bridges.

Efficient Bipolar Solution with Minimal External Components

The two stepper motor full-bridges feature Allegro’s patented mixed decay mode. This current decay control scheme results in reduced audible motor noise, increased step accuracy, and reduced power dissipation. The DC motor full-bridge current regulator operates in either fast or slow decay mode, determined by the MODE input.

Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. PHASE, ENABLE, and MODE inputs are provided for use in controlling the speed, torque, direction, and brake or coast functions of a DC motor. The stepper motor is controlled with PHASE, I0, and I1 inputs for full-, half-, or quarter-step operation. Protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover current protection. Special power-up sequencing is not required.