Method for restraining noises of digital audio frequency power amplifier

Abstract

The present invention discloses a method to restrict noise of digital power amplifiers, which ensures a same voltage at both ends of a load relying on logic control in a logic circuit after a digital power amplifier is started. A modulation signal is input after the circuit enters into a stable state, thus restricting startup noise. As a video digital power amplifier is closed and before other circuits are cut off, voltages at both ends of the load are synchronous to provide a path for current discharge and quickly release energy, thus restricting noise during shutdown.

Description

【Technical field】 [0001] The invention relates to a method for suppressing power amplifier noise, in particular to a method for suppressing switching noise of a digital audio power amplifier. 【Background technique】 [0002] Such as figure 1 Shown is the circuit structure of the existing basic digital audio power amplifier. It includes a preamplifier 10 , a modulation circuit 11 , an H-bridge switch circuit 12 , a drive circuit 13 and a logic control circuit 14 . The H-bridge switch circuit usually includes four power transistors, the four power transistors may be two NMOS transistors, two PMOS transistors, or four power transistors of the same type, such as all PMOS transistors or all NMOS transistors. [0003] With the increasingly wide application of digital power amplifiers, the quality requirements are getting higher and higher, and the noise when the digital power amplifiers are turned on and off has always been a problem that the industry expects to solve. A commonl...

AI Technical Summary

Problems solved by technology

[0007] 2. The differential voltage at both ends of the load lasts for a long time, and it is difficult to be heard if the duration is less than 10us

[0008] Due to the instability of the circuit when switching on and off, the above situation is prone to occur, resulting in noise that can be heard by the human ear.

Images