Circuit and method for generating a PWM control signal for a class-D amplifier
AssigneeRichtek Technology Corporation
InventorsJwin-Yen Guo, Shao-Ming Sun
Life of this patent
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Abstract
In a class-D amplifier, the input signal is compared with a carrier signal to generate a basic PWM signal, the PWM signal is then sent to a pulse processing unit, and by comparing with a basic periodic signal, half-width of the output PWM signal is extracted. Then, in the pulse processing unit, the half-width PWM pulse signal is used to generate a complete pulse whose width equals to the output PWM signal. The output power of the class-D amplifier can be kept as large as that by using differential input signals although the input signal is single-end and the entire signal processing path is kept single-ended.
Claims13
A circuit for generating a PWM control signal for a class-D amplifier, comprising:
- a hysteresis comparator for comparing a single-end input signal with a carrier signal to generate a basic PWM signal;
- and
- a pulse processing unit coupled to the hysteresis comparator to generate the PWM control signal having a pulse width;
- wherein the pulse processing unit extracts a half width of the PWM control signal from the basic PWM signal and a basic periodic signal, and then produces a complete pulse whose width equals to the pulse width of the PWM control signal.
A method for generating a PWM control signal for a class-D amplifier, comprising the steps of:
- (A) comparing a single-end input signal with a carrier signal to generate a basic PWM signal;
- (B) extracting a half width of the PWM control signal from the basic PWM signal and a basic periodic signal;
- and
- (C) completing a pulse of the PWM control signal from the half width of the PWM control signal.
Dependencies are inferred from the claim text.