Patent ID: 6867566
Filing Date: 2005-03-15
Classification: H02P

Abstract:
1. A motor driver circuit comprising: an H-switch circuit arranged for connection with one phase of a multi-phase step motor; a switch driver interconnected with said H-switch and a bridge control circuit; a set point generator connecting with one input to a comparator; a phase current sensing resistor connecting with said H-switch and another input to said comparator for providing a sense resistor signal to said H-switch and said comparator; and a pulse width modulation (PWM) oscillator connecting with one input to a logic gate and an output from said comparator connecting another input to said logic gate, an output from said logic gate connecting with said bridge control circuit, whereby direction and duration of current flow to said H-switch via said bridge control circuit and said switch driver is controlled by operation of said PWM oscillator and said PWM oscillator blocks output of said logic gate for a period spanning one edge of a PWM oscillator signal from said bridge control circuit.