Patent ID: 6025683
Filing Date: 2000-02-15
Classification: H02P,Y10S

Abstract:
A motor control circuit for regulating the speed of a motor having a rotor, a plurality of windings located around the rotor and configured to generate a pulsed signal representative of the rotational position of the rotor, said circuit comprising:a tachometer for receiving the pulsed signal from the motor and producing a pulse width modulated TACHOMETER signal having an on duty cycle that is proportional to the frequency at which the pulsed signal is generated;,a pulse width modulator for receiving the TACHOMETER signal and a USER.sub.-- SPEED signal representative of a user-selected speed, said pulse width modulator configured to generated a pulse width modulated SPEED.sub.-- CONTROL.sub.PWM signal that has an on-duty cycle proportional to the difference between an integral of the TACHOMETER signal and the USER.sub.-- SPEED signal; anda motor driver for receiving the pulsed signal from the motor and the SPEED.sub.-- CONTROL.sub.PWM signal for producing a plurality of HIGH.sub.-- SIDE.sub.-- CONTROL signals, each HIGH.sub.-- SIDE.sub.-- CONTROL signal being asserted to cause a separate one of the motor windings to be connected to a power source, and a plurality of LOW.sub.-- SIDE.sub.-- CONTROL signals, each LOW.sub.-- SIDE.sub.-- CONTROL signal being asserted to cause a separate one of the motor windings to be connected to ground, wherein the motor driver sequentially asserts the HIGH.sub.-- SIDE.sub.-- CONTROL signals and the LOW.sub.-- SIDE.sub.-- CONTROL signals as a function of the pulsed signal and the on-duty cycle of the SPEED.sub.-- CONTROL.sub.PWM signal.