A kind of advanced follow-up bias method and amplifier of class A audio power amplifier

Abstract

An advanced servo bias method of an A-class audio power amplifier and an amplifier. The advanced servo bias method relates to delaying a selected audio signal to be amplified and using an analog audio signal corresponding to the delayed audio signal as an audio signal which is to be input into a power amplifier for amplification. Moreover, the analog audio signal corresponding to the selected audio signal to be amplified is used for controlling to generate a bias that changes along with the amplitude of the delayed audio signal, and making a power amplification output circuit be in an A-class working state. An amplifier comprises a voltage or current bias circuit (112), a full wave rectification circuit (115), an amplitude holding circuit (114), a conversion circuit (113), an audio power amplification output circuit (111), and a delay circuit (108); The audio signal to be amplified is delayed and then enters the audio power amplification output circuit (111); after circuit processing, the analog audio signal corresponding to the audio signal to be amplified is used for controlling the output of a bias voltage or current of the voltage or current bias circuit (112). The amplifier can reduce a bias in due time, thereby reducing power consumption.

Description

technical field [0001] The invention relates to the field of audio power amplification, in particular to a leading follow-up bias method of a class A audio power amplifier and a class A audio power amplifier using the method. Background technique [0002] At present, with the development of multimedia technology, home audio power amplifiers, professional audio power amplifiers, car audio audio power amplifiers, and portable multimedia equipment audio power amplifiers are all developing rapidly, which can be divided into A, B, AB, D, G, H and other types. [0003] Among them, in the class B audio power amplifier, the power amplifier output tube is cut off half of the time in the entire signal cycle. Although the theoretical efficiency can reach 78.5%, there is a serious crossover distortion problem, and the playback sound is very bad. ; Class AB audio power amplifier, the power amplifier output tube is fully conductive when the signal is small and medium, and works in the wa...

AI Technical Summary

Problems solved by technology

There are common forms such as sliding bias, dynamic bias, real-time bias, continuous high bias, or super class A. These forms are unique, but there are generally problems of rough improvement and limited improvement, especially in establishing these biases and adjusting voltages. Or the current takes more time, obviously lags behind the input signal, produces more distortion, loses the good sound quality and sense of hearing of a true Class A audio power amplifier, and some are the size of the bias and the duration of the bias The time is not suitable, and the efficiency improvement is not obvious

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