Power supply circuit of audio frequency power amplifier

Abstract

The present invention discloses a power supply of an audio frequency power amplifier, comprising a power supply source for providing voltage to the whole power supply circuit of the audio frequency power amplifier, an audio frequency power amplifier, a normal power supply circuit for providing a working input voltage to the audio frequency power amplifier, a pre-power supply and protection circuitfor providing an input voltage having a certain rise time to the audio frequency power amplifier, and providing short circuit protection to the audio frequency power supplier, and a voltage detectingand alarm circuit for detecting the input voltage amplitude of the audio frequency power amplifier, outputting the detecting signal to control the working states of the pre-power supply and protection circuit and normal power supply circuit, and providing short circuit alarm to the audio frequency power supply circuit. The power supply circuit of the audio frequency power supply can effectively eliminate startup voice of television, provides protection and alarm when the audio frequency power supply is short-circuited, is simple, safe and reliable, as well as has low cost.

Description

【Technical field】 [0001] The invention relates to the technical field of television sets, in particular to an audio power amplifier power supply circuit which can effectively eliminate the start-up noise of the television set and provide protection when the power supply circuit of the audio power amplifier is short-circuited. 【Background technique】 [0002] At present, the sound system of a TV generally firstly inputs a small audio signal into an audio power amplifier, and then outputs it to a speaker after being amplified by the audio power amplifier, and finally the speaker emits a sound. The audio power amplifier of the TV is very important to the sound system, and the power supply of the audio power amplifier often affects the effect of the TV sound system, especially when the voltage jumps instantaneously when starting up, due to the coupling effect of the internal capacitance and inductance of the audio power amplifier, it is easy to produce Irregular audio signals are...

AI Technical Summary

Problems solved by technology

The audio power amplifier of the TV is very important to the sound system, and the power supply of the audio power amplifier often affects the effect of the TV sound system, especially when the voltage jumps instantaneously when starting up, due to the coupling effect of the internal capacitance and inductance of the audio power amplifier, it is easy to produce Irregular audio signal is output to the speaker, causing startup noise

At the same time, the TV needs a louder sound, so the sound system needs to output a large enough power, so the power supply voltage of the audio power amplifier is relatively high, and the power supply current is relatively large. When the power supply of the audio power amplifier is short-circuited, it will cause great harm.

At present, in order to eliminate the noise of starting up the TV, the power supply of the audio power amplifier generally needs the control signal generated by the TV MCU to control or use the circuit to control other links of the sound system, which has high cost and complex structure; and the short circuit protection of the power supply of the audio power amplifier is generally provided by the power supply , there are strict requirements on the power supply, which increases the cost of the power supply

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