A gain control device

Abstract

The invention provides a gain control device comprising a pre-amplifier circuit, a voltage control circuit, a modulation circuit, an amplitude detection circuit, a zero-crossing circuit, a clip protection and amplitude detection circuit, and a gain control circuit. The pre-amplifier circuit, the voltage control circuit, and the modulation circuit are sequentially connected to each other. The voltage control circuit is connected to the gain control circuit via the amplitude detection circuit and the zero-crossing circuit, respectively. The modulation circuit is connected to the gain control circuit via the clip protection and amplitude detection circuit. The gain control device provided in the invention is utilized to provide favorable audio quality while providing protection for a speaker effectively, preventing the speaker from being damaged as a result of exceeding maximum power.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a gain control device. Background technique [0002] The audio amplifier is to amplify the power of the audio signal to drive the speaker to achieve the purpose of sound amplification. In the process of audio processing, in order to improve the effect of music playback and increase the loudness of music playback, it is usually necessary to perform automatic gain control on the input audio signal to adjust the signal amplitude of the input audio signal, attenuate large-value signals, and amplify small-amplitude signals. value signal to ensure the stability of the signal amplitude. Most of the current audio power amplifiers have an automatic gain control (AGC) function. AGC is an automatic control method that automatically adjusts the gain of the amplifier circuit with the signal strength. The function of the AGC automatic gain control circuit is to automatically keep...

AI Technical Summary

Problems solved by technology

But when there are multiple groups of AGC control circuits, it is impossible to choose whether to need zero-crossing detection to change the gain

If there is a low-frequency music signal input, when the output signal exceeds the maximum power limit of the speaker, the gain must be reduced in time and quickly. If the gain must be changed after zero-crossing detection, the speaker may be damaged.

In addition, the second detection circuit of the zero-crossing detection circuit uses high threshold and low threshold levels to judge the output signal, that is, the output signal does not send the zero-crossing detection signal at the lowest point, so when changing the gain, it will still cause A certain amount of noise will affect the playback effect

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