Pulse-width modulation generator
AssigneeQualcomm Technologies International, Ltd.
InventorDavid Chappaz
Life of this patent
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Abstract
The present application relates to a pulse-width modulation generator for generating a pulse-width modulated signal, the PWM generator comprising: a PWM modulator; and a loop filter, wherein the loop filter is configured to receive an input signal and to output a filtered signal to the PWM modulator, and the PWM modulator is configured to receive the filtered signal from the loop filter and to output a pulse-width modulated signal, the PWM generator further comprising: a feedback loop coupling an output of the PWM modulator to an input of the loop filter, wherein the feedback loop includes a comb filter.
Claims17
A pulse-width modulation (PWM) generator, comprising:
- a combiner configured to produce a difference signal by subtracting a feedback signal from an input signal of the PWM generator;
- a loop filter configured to filter the difference signal and to produce a filtered signal;
- a PWM modulator configured to output a pulse-width modulated signal;
- a comb filter configured to produce the feedback signal by filtering the pulse-width modulated signal;
- and
- a signal path configured to add a delayed and amplified version of the feedback signal from the comb filter to the filtered signal from the loop filter to produce an input signal of the PWM modulator.
A method for generating a pulse-width modulated (PWM) signal, the method comprising:
- subtracting a feedback signal from an input signal to produce a difference signal;
- filtering the difference signal to produce a filtered signal;
- comparing a PWM modulator input signal with a carrier signal at a first frequency to produce a pulse-width modulated signal;
- comb filtering the pulse-width modulated signal to produce the feedback signal;
- delaying feedback signal to produce a delayed feedback signal;
- amplifying the delayed feedback signal by a constant factor to produce a delayed amplified feedback signal;
- and
- adding the delayed amplified feedback signal to the filtered signal to produce the PWM modulator input signal.
Dependencies are inferred from the claim text.