Over-temperature protection circuit for radio frequency power amplifier

Abstract

The invention relates to an over-temperature protection circuit for a radio frequency power amplifier. The circuit comprises a temperature detection circuit, a comparator circuit, a logic control circuit and a bias circuit which are connected in turn, wherein the temperature detection circuit detects the temperature of a chip and outputs the temperature to the comparator circuit, the comparator circuit outputs a trigger signal to the logic control circuit, and the logic control circuit controls the bias circuit to adjust the current of the amplifier to adjust the working temperature of the logic control circuit so as to realize protection; reference voltage is input into one end of a comparator in the comparator circuit, and the output signal of the temperature detection circuit is input into the other end of the comparator; or the output signal of the temperature detection circuit is input into the two input ends; and the temperature detection circuit consists of one or more diodes which are connected in series. When mobile communication equipment does not work, the over-temperature protection circuit can be switched off in a bias circuit control mode, and leakage current in the over-temperature protection circuit is avoided so as not to cause unnecessary energy loss; and the circuit is flexibly applied and convenient to integrate.

Description

technical field [0001] The invention relates to the technical field of radio frequency power amplifiers, in particular to an overtemperature protection circuit for radio frequency power amplifiers. Background technique [0002] As the core device in the wireless communication system, the radio frequency power amplifier (PA) should work normally in various harsh environments, such as working under severe load mismatch, high power supply voltage and high power level for a long time. All conditions will cause the current of the RF power amplifier to increase rapidly, thereby generating a lot of heat. The RF power amplifier is not good enough for heat dissipation and thermal protection, and it is easy to cause the tube to fail due to thermal breakdown. In order to avoid the problem of overheating, burning and breakdown of the RF power amplifier tube caused by the harsh surrounding environment or the unsatisfactory heat dissipation and load matching of the communication equipment...

AI Technical Summary

Problems solved by technology

In order to obtain the output power and efficiency required by various communication standards, the emitter area of ​​the output tube T3 is very large, and generally adopts a multi-finger structure. Due to the large output power and current, it is easy to cause temperature differences between fingers, resulting in Current collapse and other problems lead to burnout of the device; on the other hand, due to some external factors, such as high power supply voltage and serious load mismatch, etc., due to the insufficient thermal stability of the RF power amplifier, it is easy to overheat itself due to excessive current. burn the pipe

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