Class-D amplifier with pulse-width modulation common-mode control and associated method for performing class-D amplification
AssigneeMediatek Inc.
InventorsWen-Chieh Wang, Yu-Hsin Lin
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Abstract
A class-D amplifier includes a loop filter, a pulse-width modulation (PWM) circuit, an output circuit, and a common-mode control circuit. The loop filter receives an input signal of the class-D amplifier to generate a filtered signal. The PWM circuit converts a non-PWM signal into a PWM signal, wherein the non-PWM signal is derived from at least the filtered signal. The output circuit generates an output signal of the class-D amplifier according to the PWM signal. The common-mode control circuit monitors a common-mode level of the output signal to generate a common-mode control signal for PWM common-mode control.
Claims20
A class-D amplifier comprising:
- a loop filter, arranged to receive an input signal of the class-D amplifier to generate a filtered signal;
- a pulse-width modulation (PWM) circuit, arranged to convert a non-PWM signal into a PWM signal, wherein the non-PWM signal is derived from at least the filtered signal;
- an output circuit, arranged to generate an output signal of the class-D amplifier according to the PWM signal, wherein the output signal is a fully-differential signal;
- a common-mode control circuit, arranged to monitor a common-mode level of the output signal to generate a common-mode control signal for PWM common-mode control;
- and
- a first combining circuit, located between an output of the loop filter and an input of the PWM circuit;
- wherein the common-mode control circuit is arranged to output the common-mode control signal to the first combining circuit and the first combining circuit is arranged to combine the filtered signal and the common-mode control signal to adjust a common-mode level of the non-PWM signal, where the non-PWM signal is derived from combining at least the filtered signal and the common-mode control signal.
A class-D amplifier comprising:
- a loop filter, arranged to receive an input signal of the class-D amplifier to generate a filtered signal;
- a combining circuit, arranged to combine at least the filtered signal and the input signal to generate a non-PWM signal, wherein the combining circuit is composed of passive components only;
- an input feed-forward circuit, arranged to feed the input signal to the combining circuit;
- a pulse-width modulation (PWM) circuit, arranged to convert the non-PWM signal into a PWM signal;
- and
- an output circuit, arranged to generate an output signal of the class-D amplifier according to the PWM signal.
A method for performing class-D amplification comprising:
- performing a loop filtering operation upon an input signal of the class-D amplification to generate a filtered signal;
- performing a pulse-width modulation (PWM) operation to convert a non-PWM signal into a PWM signal, wherein the non-PWM signal is derived from at least the filtered signal;
- generating an output signal of the class-D amplification according to the PWM signal, wherein the output signal is a fully-differential signal;
- and
- monitoring a common-mode level of the output signal to generate a common-mode control signal for PWM common-mode control;
- wherein the non-PWM signal is derived from at least the filtered signal and the common-mode control signal, and the method further comprises:
- combining the filtered signal and the common-mode control signal to adjust a common-mode level of the non-PWM signal, where the non-PWM signal is derived from combining at least the filtered signal and the common-mode control signal.
A method for performing class-D amplification comprising:
- performing a loop filtering operation upon an input signal of the class-D amplification to generate a filtered signal;
- utilizing a combining circuit to combine at least the filtered signal and the input signal to generate a non-PWM signal, wherein the combining circuit is composed of passive components only;
- performing a pulse-width modulation (PWM) operation to convert the non-PWM signal into a PWM signal;
- and
- generating an output signal of the class-D amplifier according to the PWM signal.
Dependencies are inferred from the claim text.