■ General Description

ATS477 that integrates Hall sensor with output drivers is designed for electrical commutation of brush-less DC motor application. The device includes on-chip Hall voltage generator for magnetic sensing, the error amplifier that amplifies the Hall voltage, a comparator that is to provide switching hysteresis for noise rejection, the bi-direction drivers for sinking and driving large current load, and the frequency generator (FG) that provides a signal proportional to rotation speed. Internal bandgap regulator is used to provide temperature compensated bias for internal circuits and allows a wide operating supply voltage range. Built-in protection circuit and output shunt Zener diodes were applied for protecting output drivers during operating.

If a magnetic flux density is larger than threshold Bop, DO is turned to sink and DOB is turned to drive. The output state is held until a magnetic flux density reversal falls below Brp causing DO to be turned to drive and DOB turned to sink.

ATS477 is rated for operation over-temperature range from -20 oC to 85 oC and voltage range from 3.5V to 20V. The devices are available in low cost die forms or rugged SIP-4L and power SOP-7L packages.

■ Features

- On-chip Hall sensor

- Bi-direction H type output drivers for single coil

- Internal bandgap regulator allows temperature compensated operations and a wide operating voltage range

- High output sinking capability up to 250mA

- Operating voltage: 3.5V~20V

- Low output switching current noise

- Build-in shunt Zener protection for output driver

- SOP-7L provide FG output pin

- Package: SIP-4L and SOP-7L

■ Applications

- Single-coil Brush-less DC Fan

- Single-coil Brush-less DC Motor