ML4425 Datasheet | Micro Linear

July 2000 ML4425 Sensorless BLDC Motor Controller GENERAL DESCRIPTION The ML4425 PWM motor controller provides all of the functions necessary for starting and controlling the speed of delta or wye wound Brushless DC (BLDC) motors without Hall Effect sensors. Back EMF voltage is sensed from the motor windings to determine the proper mutation phase sequence using a PLL. This patented sensing technique will mutate a wide range of 3Phase BLDC motors and is insensitive to PWM noise and motor snubbing circuitry. The ML4425 limits the motor current using a constant offtime PWM control loop. The velocity loop is controlled with an onboard amplifier. The ML4425 has circuitry to ensure that...