Power amplifier capable of regulating noise

Abstract

The invention relates to a power amplifier capable of regulating noise and solving the noise interference problem suffered by general power amplifiers. The power amplifier comprises a differential motion mode integrator, an integrating and regulating unit and a switch unit. The differential motion mode integrator is used for receiving an input signal and an output signal of a differential motion mode and outputting a first signal of the differential motion mode; the integrating and regulating unit is coupled with the differential motion mode integrator and used for receiving the first signal and the output signal of the differential motion mode and outputting a second signal of a single-terminal mode; and the switch unit receives the second signal and outputs the output signal of the differential motion mode to drive a load. The invention eliminates common-mode noise by using a common-mode input signal to replace a single-terminal input signal and obtains better effect on eliminating aband stop signal by using an integrating circuit of two orders or more than two orders to replace a traditional filter.

Description

technical field [0001] The present invention relates to a power amplifier, in particular to a noise trimming power amplifier. Background technique [0002] refer to figure 1 , general power amplifiers, especially audio power amplifiers, will adopt negative feedback design to obtain a stable gain, and at the same time, in order to eliminate high-frequency noise, a low-pass filter will be connected in series, and the low-pass filter is usually an integrating circuit. Such as figure 1 As shown, the feedback circuit 110 converts the differential mode output signal pair Vo1 and Vo2 into a single-ended mode feedback signal Vsum_P. The feedback signal Vsum_P and the input signal VI then pass through the integrator 120 to filter out noise. [0003] However, since the amplifier evolved from vacuum tube to transistor, noise interference has always been the biggest problem encountered by audio power amplifiers. There are two main sources of noise, one is the power supply hum (Power...

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Problems solved by technology

However, such designs, such as figure 1 As shown, only relying on traditional filters to eliminate noise is not ideal

[0004] The second source of noise is radio frequency interference. When the radio frequency signal is close to the audio amplifier, the circuit structure with relatively poor common mode rejection ratio will receive the radio frequency signal together and become the noise interference of the audio amplifier itself. , such as the buzzing sound generated when a mobile phone is close to the speaker, while traditional audio amplifiers do not use a fully differential architecture to improve the common-mode rejection ratio

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