Quad DMOS Full-Bridge PWM Motor Driver
Allegro MicroSystems, Inc. announces its quad DMOS full-bridge driver that is capable of driving up to two stepper motors or four DC motors. Each full-bridge output is rated up to 1.2 A and 36 V. The A3988 includes fixed off-time pulse width modulation (PWM) current regulators and 2-bit nonlinear DACs (digital-to-analog converters) that allow stepper motors to be controlled in full, half and quarter steps, and DC motors in forward, reverse and coast modes. The PWM current regulator uses the company’s patented mixed decay mode for reduced audible motor noise, increased step accuracy and reduced power dissipation. Internal synchronous rectification control circuitry is provided to improve power dissipation during PWM operation. Protection features include thermal shutdown with hysteresis, under-voltage lockout (UVLO) and crossover current protection.