3-PHASE BRUSHLESS DC MOTOR CONTROLLER/DRIVER WITH BACK-EMF SENSING

The A8904SLB and A8904SLP are three-phase brushless dc motor controller/drivers designed for applications where accurate control of high speed motors is required. The three half-bridge outputs are low on-resistance n-channel DMOS devices capable of driving up to 1.2 A. The A8904 provides complete, reliable, self-contained back-EMF sensing, motor startup and running algorithms. A programmable digital frequency-locked loop speed control circuit together with the linear current control circuitry provides precise motor speed regulation.

Features

■ Pin-for-pin replacement for A8902CLBA

■ Startup commutation circuitry

■ Sensorless commutation circuitry

■ Option of external sector data tachometer signal

■ Option of external speed control

■ Oscillator operation up to 20 MHz

■ Programmable overcurrent limit

■ Transconductance gain options: 500 mA/V or 250 mA/V

■ Programmable watchdog timer

■ Directional control

■ Serial Port Interface

■ TTL-compatible inputs

■ System diagnostics data out ported in real time

■ Dynamic braking through serial port or external terminal