Patent ID: 7705550
Filing Date: 2010-04-27
Classification: H02P

Abstract:
1. A device comprising: a pulse-width modulation (PWM) motor drive circuit having a first output node and a second output node, wherein the second output node is configured to couple to a motor, wherein the PWM motor drive circuit is configured to provide a first PWM signal at the first output node and provide a second PWM signal at the second output node, and wherein the first PWM signal precedes the second PWM signal by a predetermined time period; and a noise suppression circuit having a first input node, a second input node, and an output node, wherein the first input node is coupled to the first output node of the PWM motor drive circuit, wherein the noise suppression circuit is configured to receive the first PWM signal from the PWM motor drive circuit and to receive, at the second input node, output signals from a Hall-effect device that is coupled to the motor, wherein the output signals from the Hall-effect device indicate a rotational position and speed of the motor and have one or more transient noise spikes, wherein the noise suppression circuit is further configured to detect edges of the first PWM signal and to provide an output signal at the output node that corresponds to output signals from the Hall-effect device, and wherein the noise suppression circuit output signal is configured to be provided at an existing level for a predetermined time duration in response to detecting each edge of the first PWM signal.