power amplifier

Abstract

The invention provides a power amplifier which comprises output tubes, mirroring tubes and overcurrent tubes, wherein grid electrodes of the output tubes are connected to signal input ends, drain electrodes of the output tubes are connected to the signal output ends, and source electrodes of the output tubes are connected to constant voltage sources; grid electrodes of the mirroring tubes are connected to signal input ends, source electrodes of the mirroring tubes are connected to the constant voltage sources through sampling resistors, the quantities of currents flowing through the source electrodes of the output tubes are setting times of those of currents flowing through the source electrodes of the mirroring tubes, and drain electrodes of the mirroring tubes are connected to the signal output ends; and source electrodes of the overcurrent tubes are connected to the constant voltage sources, the sampling resistors are connected between the source electrodes and grid electrodes of the overcurrent tubes, and drain electrodes of the overcurrent tubes are connected to the signal output ends. The power amplifier is provided with an overcurrent protection link, when overcurrent happens, the size of output current can be automatically limited, and the purpose of overcurrent protection is achieved; and the consumption of electric energy can be reduced, the influence of the power amplifier on output power of a load can be reduced, and the power amplifier can be applied to a large-power load.

Description

technical field [0001] The invention relates to circuit structure technology, in particular to a power amplifier. Background technique [0002] In the internal analog electronic circuits of various electronic instruments, meters and portable communication devices, power amplifiers are usually provided to amplify the output power of the electronic circuits to supply power to the load. When the load is overloaded, the output current of the power amplifier will exceed its normal current, which may cause damage to the entire electronic circuit and the load. Therefore, an over-current protection link must be added to the power amplifier to limit the output current to a fixed range. Inside, the electronic circuit and the load are protected in the event of a fault such as overload. [0003] image 3 The circuit diagram of the power amplifier provided for the prior art, such as image 3 As shown, the power amplifier contains an overcurrent protection link, and the protection circui...

AI Technical Summary

Problems solved by technology

[0009] It can be seen from the above description that the power amplifier is equipped with an over-current protection link, which can limit the output current and achieve the purpose of over-current protection. However, when this power amplifier is working, due to RE 1 and RE 2 current flows, and the RE 1 and RE 2 The current flowing on is the amplified current, RE 1 and RE 2 It will consume a large part of the power, so it will not only cause a waste of electric energy, but also cause the power amplifier to be damaged due to overheating after working for a long time, which will affect the output power of the power amplifier to the load, so it is not suitable for high-power loads

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