Allegro MicroSystems Debuts A3932 Motor Controller IC
Allegro MicroSystems Europe (UK) recently debuted the A3932, a three-phase brushless dc motor controller IC. The device features a high-current, gate-drive capability of 1.25A for gate turn-on and 2.5A for gate turn-off. The company reports that it can drive a wide range of MOSFETs, and can support motor-supply voltages from 12V to 50V.
The new A3932, which integrates a boot-strapped high-side driver, also has internal fixed, off-time, pulse-width-modulated, current-control circuitry. The peak load-current limit is set by the user's selection of an input reference voltage and external sensing resistor. In addition to speed and direction control functions, the circuit features a brake input, a fault-diagnostic output and a tachometer output. Fast and slow current-decay modes can be implemented.
The fixed off-time pulse duration for the A3932 is set by a user-selected external RC timing network. For added flexibility, the PWM input can be used to provide speed or torque control. The device includes optional synchronous rectification, which will short out the current path through the power MOSFET's intrinsic body diodes during the PWM off-cycle current decay. Power MOSFET protection features include a gate-source voltage monitor, a bootstrap capacitor charging-current monitor, under-voltage monitoring, motor-lead short to supply or ground protection, and thermal shutdown.
The A3932 is supplied in a 32-pin PLCC package.