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Sensorless brushless DC motor controller allows easy integration into customers’ applications

Sensorless brushless DC motor controller allows easy integration into customers’ applications

06 January 2015

The A4963 from Allegro MicroSystems Europe is a new 3-phase sensorless brushless DC motor controller IC that can easily be customised for integration into users’ applications.

The new device is designed for use with external complementary p-channel and n-channel power MOSFETs. Reliable sensorless startup and run commutation can quickly be customised for individual motors and loads by adjusting a few simple default parameters, with considerable saving of design time. It can be used as a stand-alone controller communicating directly with an electronic control unit or in a close-coupled system with a local microcontroller (MCU).

The A4963 fits a wide range of applications since its output current requirements can be scaled up or down with external MOSFET selection. It also has a wide DC supply voltage range of 4.2 V to 50 V.

The A4963 controls a motor using block commutation (with trapezoidal drive waveforms) where phase commutation is determined by monitoring the motor back EMF without the need for Hall-effect position sensors. The sensorless start-up scheme allows the device to operate over a wide range of motor and load combinations including high or low inertial or friction loads.

The A4963 can operate over a motor speed range from less than 100 rev/min to more than 30,000 rev/min, depending on the supply voltage and motor capability. Several operational modes are available, including closed-loop speed control, duty-cycle (voltage) control, and current (torque limit) control. Operating mode and control parameters can be altered through an SPI-compatible serial interface or through adjustable default settings preloaded into the on-chip EEPROM memory.

Motor operation is through a single-line low-frequency PWM duty-cycle control input. An open-drain output is provided to report motor commutation frequency or electrical cycle frequency. Startup (inrush) current and peak motor current are limited by an integrated fixed-off-time PWM current limiter.

Integrated diagnostics provide indication of undervoltage, overtemperature, lost synchronisation, and power bridge faults, and can protect the power switches under most short-circuit conditions. Faults are indicated by a single open-drain output.

The A4963 motor controller is targeted at the consumer, industrial and white goods markets, with end applications to include pumps, blowers, power and garden tools, hair dryers, portable mixers, and airborne drones.

The A4963GLPTR-T is provided in a small, thermally enhanced 20-pin TSSOP package with exposed thermal pad.

About Allegro
Allegro MicroSystems, LLC is a leader in developing, manufacturing and marketing high-performance semiconductors. Allegro's innovative solutions serve high-growth applications within the automotive market, with additional focus on office automation, industrial, and consumer/communications solutions. Allegro is headquartered in Worcester, Massachusetts (USA) with design, applications, and sales support centers located worldwide. Further information about Allegro can be found at

Allegro MicroSystems Europe, headquartered in Chertsey, United Kingdom, is the European sales and marketing operation, and operates a network of representatives and distributors throughout Europe.  Allegro also has an engineering design centre in Edinburgh in Scotland and an application and marketing centre in Annecy in France.

  • Allegro MicroSystems, LLC
    115 Northeast Cutoff
    Worcester, MA 01606
    United States / America
    Tel.: +1-508-854-5359
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