ML4428 Datasheet | Micro Linear

April 1997 PRELIMINARY ML4428- Sensorless Smart-Start™ BLDC PWM Motor Controller GENERAL DESCRIPTION The ML4428 motor controller provides all of the functions necessary for starting and controlling the speed of delta or wye-wound Brushless DC (BLDC) Motors without the need for Hall Effect sensors. Back-EMF voltage is sensed from the motor windings to determine the proper mutation phase sequence using PLL techniques. The patented back-EMF sensing technique used will mutate virtually any 3-phase BLDC motor that has at least a 30% variation in inductance during rotation and is insensitive to PWM noise and motor snubbing circuitry. The ML4428 also utilizes a patented start-up technique...