Allegros New Low Voltage, Full Bridge Brushless DC Motor Driver Integrates Hall Element Commutation Circuitry to Drive Vibration Motors
August 7, 2007—
Allegro Microsystems introduced a new full bridge motor drive designed to drive low voltage bi-polar brushless D motors.
Commutation of the motor is achieved by use of a single Hall element sensor to detect the rotational design position of an alternating-pole ring magnet. A high density CMOS semiconductor process allow integration of all the necessary electronics, including a Hall element sensor, motor control circuitry, and full output bridge. Low voltage design techniques were employed to achieve design functionality down to 1.8 V VDD.
According to the company's press release, the fully integrated single chip solution provides additional reliability including reverse battery protection and output short circuit protection and eliminates the need for external support components.
A soft-switching algorithm reduces audible switching noise and EMI interface. A micro power sleep mode can be enabled by an external signal to reduce current consumption for battery management in portable electronic devices. This feature allows for the removal of a FET transistor for switching the device on and off. In addition, the device offers an active function for motor braking, which can be used to improve stop/start cycles for the caller ID feature in vibration mode.