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 commutation phase sequence using a PLL. This patented sensing technique will commutate a wide range of 3-Phase BLDC motors and is insensitive to PWM noise and motor snubbing circuitry.

FEATURES

■Stand-alone operation

■Motor starts and stops with power to IC

■On-board start sequence: Align->Ramp->Set Speed

■Patented Back-EMF commutation technique provides jitterless torque for minimum “spin-up” time

■Onboard speed control loop

■PLL used for commutation provides noise immunity from PWM spikes, compared to noise sensitive zero crossing technique

■PWM control for maximum efficiency

■Direct FET drive for 12V motors; drives high voltage motors with IC buffers from IR, IXYS, Harris, Power Integrations, Siliconix, etc.