Low-voltage motor driver

Sept. 13, 2007
The A1442 full-bridge motor driver from Allegro MicroSystems Inc., Worcester, Mass., works for bipolar brushless dc motors at voltages down to 1.8 V.

A single Hall-element sensor detects rotational position of an alternating-pole ring magnet for motor commutation. A high-density CMOS semiconductor process integrates all the necessary electronics on a single chip, including the Hall sensor, motor control circuitry, and a full output bridge. The fully integrated design boosts reliability — including reverse-battery protection and output-short circuit protection — and eliminates external support components.

The A1442 employs a soft-switching algorithm to lower audible switching noise and EMI interference. A sleep mode triggered by an external signal cuts current consumption in portable electronic devices. The feature also eliminates an FET for switching the device on and off.

The A1442 targets space-constrained vibration motor applications such as cellular phones, pagers, electronic toothbrushes, handheld video-game controllers, and low-power fan motors. It comes in a lead-free, six-pin microlead frame package that is said to be the thinnest MLP available.

Allegro MicroSystems Inc., Worcester, MA, www.allegromicro.com

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