A4962: Sensorless BLDC Controller

The A4962 is a three-phase, sensorless, brushless DC (BLDC) motor controller for use with external complementary P-channel and N-channel power MOSFETs and is specifically designed for automotive applications.

The A4962 can be used as a stand-alone controller communicating directly with an electronic control unit (ECU) or it can be used in a close coupled system with a local microcontroller (MCU).

The motor is driven using block commutation (trapezoidal drive) where phase commutation is determined, without the need for independent position sensors, by monitoring the motor back-EMF (bemf). The sensorless start-up scheme allows the A4962 to operate over a wide range of motor and load combinations.

Dedicated circuits allow the A4962 to operate over a wide range of motor speeds, from less than 100 rpm to in excess of 30,000 rpm, depending on the supply voltage and motor capability.

Several operational modes are available including duty-cycle (voltage) control, current (torque limit) control and closed loop speed control. Operating mode and control parameters can be altered through an SPI compatible serial interface. Motor operation is controlled by a programmable PWM input that can be used to define the motor operating state and provide the proportional input for the selected operating mode. Integrated diagnostics provide indication of under voltage, over temperature and power bridge faults and can protect the power switches under most short circuit conditions. Faults are indicated by a single open drain output than can be used to pull the PWM input low.

The A4962 is provided in a small, thermally enhanced 20-pin TSSOP with exposed thermal pad.