Circuit structure for realizing dead time exemption in Class D audio power amplifier

Abstract

The invention relates to a circuit structure for realizing dead time exemption in a Class D audio power amplifier. The circuit structure comprises a pulse width modulator and a driving stage circuit. The driving stage circuit is in a threshold adaptive driving stage. The threshold adaptive driving stage comprises two FETs (Field Effect Transistors). The drains of the two FETs are communicated with a loudspeaker. The threshold adaptive driving stage controls the conduction thresholds of the two FETs and alternately conducts the two FETs. By using the circuit structure for realizing dead time exemption in the Class D audio power amplifier provided by the invention, the through current possibly existing in a Class D power amplification circuit can be effectively suppressed, the risk of circuit damage caused by the through current is reduced, the switching power loss is decreased, the dead time which is required to be set for the through current in the prior art is avoided, the signal distortion caused by the setting of the dead time is reduced, and the negative effect caused by the set dead time is fundamentally eliminated. Moreover, the circuit structure for realizing dead time exemption in the Class D audio power amplifier has the advantages of simple structure, low cost and wide application scope.

Description

technical field [0001] The present invention relates to the technical field of circuit structures, in particular to the technical field of audio power amplifiers, and specifically refers to a circuit structure for eliminating dead time in a Class D audio power amplifier. Background technique [0002] Class D power amplifier, that is, digital audio power amplifier, is a common power amplifier in the market. The topology of the bridge circuit of all Class D power amplifiers requires a certain dead time to generate a turn-on delay. The turn-on delay is It is intentionally added to the bridge circuit to prevent the upper and lower drive tubes from conducting at the same time and causing breakdown. The purpose of setting the dead time is to avoid the damage of the circuit caused by the through current. The reason for the through current is that the upper and lower field effect transistors are turned on at the same time during the switching phase. Ideally, the top tubes are clos...

AI Technical Summary

Problems solved by technology

The main design idea of ​​the prior art is how to adjust and optimize the dead time, and reduce the negative effects brought by the dead time, but there is no way to directly or fundamentally eliminate the dependence on the dead time, so as to improve the circuit completely. Performance and reliability; In addition, in the process of adjusting and optimizing dead time, it is always necessary to balance switching loss, shoot-through risk, and distortion performance, which are mutually restrictive and trade off.

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