Atmel rolls gate driver ICs for automotive BLDC motor-control applications

April 06, 2011 //By Christoph Hammerschmidt
Atmel Corporation has developed a new set of highly-integrated system basis gate driver ICs. The Atmel ATA6843 and ATA6844 devices are new members of the company's extensive gate driver family designed for 3-phase brushless DC (BLDC) motor control applications including turbo chargers, waste gates, EGR, pumps, fans, power window, power doors and power seats.

The new gate driver chips feature six-output stages for direct motor control when combined with an Atmel AVR microcontroller (MCU), and an on-chip Atmel automotive LIN transceiver IP for in-car communication.

Atmel claims that the ATA684x are the only products in the industry to incorporate all the essential functional blocks to supply and monitor a microcontroller in BLDC motor control applications. This feature enables a smaller footprint for applications with limited space and increases the overall system safety.

With most automotive BLDC motor applications located in hot under-the-hood environments, the ability to withstand extremely hot temperatures is a device requirement. The new Atmel ATA6844 is a high-temperature version to operate at chip temperatures of up to 200°C. The device is manufactured in Atmel's own state-of-the-art BCD-on-SOI technology SMART-I.S for extreme temperatures, and enables direct attachment of the ECU to hot actuators for short wiring and optimized construction.

Atmel automotive-qualified AVR microcontrollers are ideally suited to support the new system basis gate driver ICs in various BLDC motors with Hall sensors as well as sensorless BLDC motors with back-electromagnetic force (BEMF) sensing. With the devices' six input stages, the MCU individually controls each of the six output stages. The MCU also defines the adjustable overcurrent detection threshold of the ATA6843/44 to enable a current monitoring tailored to the various types of power MOSFETs used in the application.

The chips contain comprehensive protection and diagnostic functions, such as monitoring of overtemperature, overvoltage, undervoltage, short-circuit conditions and charge-pump failures. All incidents are communicated via three-diagnostic outputs to the microcontroller to enable appropriate countermeasures. A coast function allows simultaneous disabling of all six output stages in case of emergency. The on-board integrated watchdog independently monitors the MCU to increase the overall system safety, eliminating an additional external component. Dangerous short-circuit currents caused by faulty control signals are prevented from the pin-programmable timer stage that allows users to set a dead time for disabling unintended