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US 2009/0015327 A1Published application
Switching audio power amplifier with de-noise function
AssigneeHimax Analogic, Inc.
InventorsKuo-Hung Wu, Po-Yu Li
Life of this patent
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Abstract
The invention provides a switching audio power amplifier with de-noise function including a pulse width modulator, a de-noise circuit and a bridge circuit. The pulse width modulator performs pulse width moderation to generate the first and second PWM signals according to an input audio signal. The de-noise circuit receives the first and second PWM signals. And the bridge circuit conducts a driving current alternately flowing to and from a load according to the control signals output from the de-noise circuit.
Claims25
A switching audio power amplifier, comprising:
- a pulse width modulator, for generating a first pulse width modulation (PWM) signal and a second PWM signal, each of which comprising a pulse width modulated according to an input audio signal;
- a de-noise circuit, for delaying the second PWM signal to increase a phase difference between the first and second PWM signals when a phase difference is smaller than a threshold;
- and
- a bridge circuit, having a plurality of switches controlled by the first PWM signal and the delayed second PWM signal to conduct a driving current alternately flowing to and from a load.
1 more element
A switching audio power amplifier, comprising:
- a first comparator, for generating a first pulse width modulation (PWM) signal according to a comparison between a first reference signal and a first input audio signal;
- a second comparator, for generating a second PWM signal according to a comparison between a second reference signal and the first input audio signal;
- a control logic unit, for generating a third PWM signal and a fourth PWM signal according to levels of the first and second PWM signals;
- a de-noise circuit, for increasing a pulse width of the third PWM signal when the pulse width of the third PWM signal is smaller than a threshold, increasing a pulse width of the fourth PWM signal when the pulse width of the fourth PWM signal is smaller than the threshold, and outputting a fifth PWM signal and a sixth PWM signal;
- and
- a bridge circuit, having a plurality of switches controlled by the fifth and sixth PWM signals to conduct a driving current alternately flowing to and from a load.
3 more elements
Dependencies are inferred from the claim text.