Noise elimination device of digital audio power amplifier

Abstract

The invention belongs to the field of digital audio power amplifier systems, and particularly relates to a noise elimination device of a digital audio power amplifier. The noise elimination device is mainly composed of an integrator, a comparator, a controllable switch and a delay circuit. The integrator is composed of a transconductance amplifier, an external circuit C1, an external circuit C2 and an external circuit R1, a positive feedback loop is formed, and a triangular waveform is generated at the output end VOTA. The comparator generates continuous square waves by comparing the output signal of the amplifier with the value of the power supply voltage. And the controllable switch S controls whether the positive feedback loop works or not according to the opening and control signals of the circuit. The delay module designs delay time through an RC circuit, and reasonably designs the values of resistors R1 and C1 in combination with the requirements of the system for the circuit frequency, so that the output of the amplifier oscillates up and down at bias voltage. The method has the advantages that the system can immediately enter a normal working state, the starting time is shortened, and the 'click' noise is eliminated.

Description

technical field [0001] The invention belongs to the field of digital audio power amplifier systems, and in particular relates to a noise elimination device for digital audio power amplifiers. Background technique [0002] With the development of mobile devices and audio systems, audio power amplifiers are widely used. Although filterless digital audio power amplifiers have relatively good characteristics in terms of dynamic range performance and efficiency, "click" noise has always limited the application of digital audio power amplifiers in some devices. Therefore, "click" noise cancellation technology becomes particularly important in digital audio power amplifiers. When the entire circuit system is turned off, the transconductance amplifier will be offset, which will cause the integration capacitor to charge to the highest level, and when the entire system is turned on, it will cause the integration capacitor to discharge for a long time. In addition, digital audio powe...

AI Technical Summary

Problems solved by technology

When the entire circuit system is turned off, the transconductance amplifier will have an offset, which will cause the integration capacitor to charge to the highest level, and when the entire system is turned on, it will cause the integration capacitor to discharge for a long time

In addition, digital audio power amplifiers often use a closed loop to improve the performance of the amplifier. In this way, the feedback signal is superimposed on the input signal, which sometimes saturates the output signal of the integrator, thereby making the pulse modulator invalid, and the output signal is always high or low. Level, after several cycles, the output waveform is distorted, and a noise similar to "click" is emitted when the output passes through the speaker

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