Patent ID: 8144880

Claim:
An audio amplifier capable of performing self-oscillation comprising: a plurality of sub-audio amplifier sets, where each of the plurality of sub-audio amplifier sets comprises: a sub-audio amplifier comprising: a first comparator having a positive input terminal coupled to a reference voltage source; a first resistor having a first terminal coupled to a negative input terminal of the first comparator, and having a second terminal coupled to an audio input terminal of the sub-audio amplifier; a second resistor having a first terminal coupled to a negative input terminal of the first comparator; a third resistor having a first terminal coupled to the negative input terminal of the first comparator, and having a second terminal coupled to a feedback input terminal of the sub-audio amplifier; a second comparator having a negative input terminal coupled to the reference voltage source, a positive input terminal coupled to an output terminal of the first comparator, and an output terminal coupled to the audio output terminal of the sub-audio amplifier; and a first capacitor having a first terminal coupled to the negative input terminal of the first comparator, and a second terminal coupled to the positive input terminal of the second comparator; an audio source coupled to the audio input terminal of the sub-audio amplifier; a clock switch coupled to a clock input terminal of the sub-audio amplifier; a pre-driver coupled to an audio output terminal of the sub-audio amplifier; a transistor set having a first input terminal coupled to a first output terminal of the pre-driver, and a second input terminal coupled to a second output terminal of the pre-driver; an inductor having a first terminal coupled to an output terminal of the transistor set; and a second capacitor having a first terminal coupled to a second terminal of the inductor, and a second terminal coupled to ground; a clock source coupled to a plurality of clock switches of the plurality of sub-audio amplifier sets; and a speaker coupled to the second terminal of the inductor in each sub-audio amplifier set of the plurality of sub-audio amplifier sets; wherein the sub-audio amplifier is electrically connected to the clock source when the clock switch is short-circuited, and the sub-audio amplifier is electrically disconnected from the clock source when the clock switch is open-circuited.