A5947: Three-Phase Sensorless Fan Driver IC

The A5947 three phase motor driver IC incorporates sensorless sinusoidal drive to minimize vibration for a wide variety of fan applications. Sensorless control eliminates the requirement for Hall sensors.  As automotive industry continues to improve efficiency, the market for BLDC fan drivers continue to grow.  A5947, highly efficient sinusoidal algorithm is designed to meet the market demand while providing an easy to implement code free solution.

A5947 is an ideal solution to address a wide range of cooling fan systems including automotive seat ventilation, battery cooling, ADAS GPU/CPU and server/telecom cooling fans.  A flexible closed-loop speed control system is integrated into the IC. EEPROM is used to tailor the common functions of the fan speed curve to a specific application. 

The device has built in full sinusoidal sensorless BLDC control algorithm and programmable speed curve that eliminates the need of external micro controller and software development. It reduces PCB space by including multiple external components including MOSFETs.  Allegro’s proprietary algorithm includes Zero Torque Position Detection (ZTPD) and Automatic Phase Advance not only improve startup performance but also enhance motor efficiency at high speed.  

The A5947 is available in two packages including a 28-contact 5 mm × 5 mm QFN with exposed thermal pad (suffix ET) and a 24-contact eTSSOP (suffix LP).