Sensorless sinusoidal three-phase gate controller reduces noise for automotives

Providing flexible, low audible noise and vibration for the automotive market, the A4964 is specifically designed for engine cooling fans and oil and water pumps. 

It is designed to provide the motor control functions in a system where a small microcontroller provides the communication interface to a central engine control unit (ECU) and intelligent fault and status handling, says Allegro Microsystems Europe. 

The A4964 provides the supply and watchdog for the microcontroller and the high-voltage interfaces between the microcontroller and the central ECU and ignition switch.  It can operate as an independent single chip remote motor controller, adds Allegro.

The motor is driven using a three-phase sinusoidal current drive where phase commutation is determined, without the need for independent position sensors, by monitoring the motor back-EMF.  The sensorless start-up scheme includes forward and reverse pre-rotation (windmill) detection and synchronisation, and allows the device to operate over a range of motor and load combinations.

The A4964 offers three control modes, open loop (voltage) control, current (torque limit) control, and closed-loop speed control which allows it to be used in a wide range of applications. 

Control mode, operating mode, and bridge parameters are programmed through an SPI-compatible serial interface. A single current sense amplifier provides peak current limiting and average current measurement through the serial interface. 

Integrated diagnostics provide indication of under-voltage, over-temperature, and power bridge faults and can protect the power switches under most short-circuit conditions.

The A4964 is supplied in 36-terminal QFN and a 32-lead QFP package options, both with exposed thermal pad for enhanced power dissipation. 

Allegro MicroSystems develops and manufactures semiconductors, serving the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts, USA, and has design, applications, and sales support centres located worldwide.

Allegro MicroSystems Europe, is headquartered in Chertsey, UK and the company has a technical and marketing centre in Heidelberg in Germany. Allegro also has an engineering design centre in Edinburgh, Scotland and a technical and marketing centre in Annecy in France.


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