Intelligent Controller Drives Small Motors

Targeting small motors found in industrial, home, and office electronics, the MC34929 three-phase brushless dc motor driver integrates over-temperature, under-voltage, and stalled-rotor protection circuitry. The device, in a 24-pin, 4 mm x 4 mm x 1 mm QFN package, operates with supply voltages from 8V to 28V and provides a continuous motor drive current up to 1A. Integrating a three-phase, hall-effect sensor interface and a hall-sensor voltage supply, it can drive motors autonomously with a pushbutton or switch interface or under the control of an external microcontroller. A state machine accommodates several modes of operation including clockwise, counterclockwise, run/stop, brake, variable speed, and torque current limit. Price for the MC34929 is $1.42 each/10,000. FREESCALE SEMICONDUCTOR INC., Austin, TX. (800) 521-6274.