Non-filter D type audio amplifier based on chaotic spread-spectrum modulation technique

Abstract

The invention discloses a no-filter D-class audio amplifier based on the chaos frequency spreading modulating technology, mainly comprising a chaos frequency spreading triangle-wave generator, a comparator and a full-bridge output-stage circuit, wherein the chaos frequency spreading triangle-wave generator is used for generating chaos frequency spreading triangle-wave signals. When an audio signal is sent, the comparator is used for comparing voltage values of the audio signal and the chaos frequency spreading triangle-wave signal to output a square wave signal with changeable dutyfactor. After the power of the square signal is amplified by the full-bridge output-stage circuit, the square signal is outputted to a loudspeaker and recovered to the audio signal above the loudspeaker. The invention has the following advantages that the electromagnetic interference of the output signal of the D-class amplifier is effectively inhibited under the condition of no filter, the integration is easy, the chip area is saved, and the linearity of the chaos frequency spreading triangle wave used as the PWM carrier wave is not influenced by the modulation signal (chaos sequence) is guaranteed, thus, the distortion factor of the output audio signal is not influenced.

Description

technical field [0001] The invention relates to the technical field of audio power amplifiers, in particular to a filter-free Class D audio amplifier based on chaotic spread spectrum modulation technology. Background technique [0002] Class D audio amplifiers are widely used in portable devices because of their very high efficiency due to their switching output stages. However, the high-frequency square wave signal output by the class D audio amplifier contains a large number of harmonic components, and the electromagnetic interference (EMI) problem caused by it is one of the difficult problems in the current electronic system design. The traditional solution is to use LC filters to suppress conducted EMI, and metal shields to suppress radiated EMI. The disadvantage of these solutions is that they increase the volume and weight of the entire system, which not only sacrifices portability, but also increases costs. [0003] Different from the traditional method, the new sol...

AI Technical Summary

Problems solved by technology

However, the pseudo-random sequence needs to be generated by complex digital circuits, and the problem of digital-analog mixing should be considered when integrating with a class D audio amplifier.

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