公开(公告)号：US09660632B1

公开(公告)日：2017-05-23

申请号：US14971109

申请日：2015-12-16

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： John L. Melanson ,  Paul Lesso

IPC: H03K7/08

CPC classification number: H03K3/011 ,  H03F1/303 ,  H03F3/2171 ,  H03K7/08 ,  H03M1/822

Abstract: Noise introduced in an output signal of a pulse-width modulator (PWM) may be reduced by changing the time duration that a switch is driving the output node. Because the power supplies coupled to the switches are the source of noise in the output signal of the PWM, the time duration that the power supplies are driving the output may be reduced to obtain a subsequent reduction in noise in the output signal. For example, when a small signal is desired to be output by the PWM, the switches may be operated for shorter time durations. Thus, the switches couple the noise sources to ground for a duration of a cycle to reduce contribution of noise to the output. But, when a larger signal is desired to be output by the PWM, the switches may be operated for longer time durations or the conventional time durations described above.

公开(公告)号：US10230355B2

公开(公告)日：2019-03-12

申请号：US15790863

申请日：2017-10-23

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： John L. Melanson ,  Paul Lesso

IPC: H03K3/011 ,  H03M1/82 ,  H03F3/217 ,  H03K7/08 ,  H03F1/30

Abstract: Noise introduced in an output signal of a pulse-width modulator (PWM) may be reduced by changing the time duration that a switch is driving the output node. Because the power supplies coupled to the switches are the source of noise in the output signal of the PWM, the time duration that the power supplies are driving the output may be reduced to obtain a subsequent reduction in noise in the output signal. For example, when a small signal is desired to be output by the PWM, the switches may be operated for shorter time durations. Thus, the switches couple the noise sources to ground for a duration of a cycle to reduce contribution of noise to the output. But, when a larger signal is desired to be output by the PWM, the switches may be operated for longer time durations or the conventional time durations described above.