Driver IC for fan and blower applications
The new A4941 from Allegro MicroSystems Europe is a three-phase, sensorless, brushless DC motor driver IC designed for fan and blower applications in the white goods and office automation sectors.
Key features of the new device, which is housed in a small eTSSOP package, include sensorless commutation, a wide (5-16 V) supply voltage range, 1.25 A peak output current, -40° to +105°C operating temperature range, lock detection with auto restart, and soft switching for reduced audible noise.
The motor drive system in the A4941 consists of three half-bridge NMOS outputs, back EMF sensing circuitry, adaptive commutation control and a state sequencer. The sequencer determines which output devices are active, while the back EMF sensing circuits and adaptive commutation circuits determine when the state sequencer advances to the next state.
