Grid voltage stabilizing circuit of LDMOS power amplifier tube

Abstract

The invention discloses a grid voltage stabilizing circuit of an LDMOS power amplifier tube. The grid voltage stabilizing circuit comprises a power supply filter circuit, a step-down circuit and a linear voltage stabilizing circuit, the power supply filter circuit is used for filtering ripples of power supply voltage and signal crosstalk of other units, and the output end of the power supply filter circuit is connected with the input end of the voltage reduction circuit through the voltage division power resistor; the step-down circuit comprises a voltage regulator and a plurality of rectifying and filtering capacitors; the linear voltage stabilizing circuit comprises an enable switch circuit and a low-dropout linear voltage stabilizer, and the enable switch circuit is used for controlling opening and closing of the low-dropout linear voltage stabilizer; and an enable pin of the low-dropout linear voltage stabilizer is connected with the switching circuit, and an output pin of the low-dropout linear voltage stabilizer is connected to a grid electrode of the LDMOS power amplifier tube through a potentiometer. According to the invention, the radio frequency amplification index of the LDMOS power amplifier tube can be remarkably improved, and meanwhile, the overall stability and good linearity of the radio frequency amplification circuit are realized.

Description

technical field [0001] The invention belongs to the technical field of short-wave communication, and in particular relates to a gate voltage stabilizing circuit of an LDMOS power amplifier tube. Background technique [0002] In the shortwave communication system, the power amplifier module is an indispensable part. In the working principle of the shortwave radio station, the sound and various data information are converted into small signals after a series of processing and sent to the power amplifier unit, and the small signal is realized by the power amplifier unit. The fixed gain amplification, the radio frequency signal amplified to the rated power passes through the filter to filter the harmonics and the impedance matching of the antenna feeder system to transmit, so as to realize the information transmission of the shortwave radio station. The previous generation of RF amplifier circuits used bipolar transistors as the core RF amplifier components. Due to the inherent ...

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Problems solved by technology

The gate is used as a small signal input terminal, any small signal such as the power supply ripple in the bias power supply is easily amplified by the power amplifier tube, which seriously affects the purity of the RF signal and the requirements of various indicators such as harmonics and intermodulation, and even leads to The internal protection or burning of the power amplifier tube

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