Audio amplitude limiting circuit and equipment with power rail tracking characteristic based on single power supply

Abstract

The invention discloses an audio amplitude limiting circuit and equipment with a power rail tracking characteristic based on a single power supply, and relates to the technical field of electronics. The key points of the technical scheme are that the audio amplitude limiting circuit comprises an amplitude limiting threshold calculation circuit, a window voltage comparator, an optocoupler and an audio amplifier; the amplitude limiting threshold calculation circuit is used for detecting the power supply voltage and the midpoint voltage of the output operational amplifier power supply, and calculating the high threshold voltage and the low threshold voltage of the window voltage comparator according to the power supply voltage and the midpoint voltage; the window voltage comparator is used for detecting whether an output signal of the audio amplifier exceeds a voltage interval between the low threshold voltage and the high threshold voltage; and the audio amplifier is used for carrying out voltage division processing on the midpoint voltage to obtain a midpoint reference voltage, carrying out operation processing on the audio input signal and then transmitting the audio input signal to the power amplifier. According to the invention, power rail tracking can be realized, the method can be applied to an amplitude limiting circuit in a single-power-supply scene, and the audio power amplifier is ensured not to be subjected to peak clipping under the condition of power voltage fluctuation.

Description

technical field [0001] The invention relates to the field of electronic technology, more specifically, it relates to an audio frequency limiting circuit and equipment based on a single power supply and having power rail tracking characteristics. Background technique [0002] In order to avoid output peak clipping damage to the speaker unit when a large signal is input, the audio power amplifier generally needs to be equipped with a limiter circuit to prevent output peak clipping. [0003] At present, the commonly used schemes mainly include: (1) Use the full-bridge rectifier to detect the output signal, and use the detected signal to drive the optocoupler to control the gain of the operational amplifier to achieve limiting. Due to the influence of nonlinearity and temperature coefficient, it is difficult to set the output amplitude accurately, and the discrete type is large. Another disadvantage is that the power rail tracking cannot be realized, and the problem of output pe...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems of high cost, great difficulty, poor precision, inconvenient use of single power supply, and inability to realize power rail tracking and voltage fluctuations in the audio frequency limiter circuit in the prior art When the power amplifier output is large, the problem of peak clipping will still occur. The purpose of the present invention is to provide an audio frequency limiting circuit and equipment based on a single power supply with power rail tracking characteristics.

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