Biasing circuit of power amplifier

Abstract

The invention provides a biasing circuit of a power amplifier. The biasing circuit at least comprises a voltage generating module and a direct current biasing buffer outputting module, wherein the voltage generating module is connected with an external biasing voltage and used for processing the external biasing voltage to output stable voltage output, and the direct current biasing buffer outputting module is connected to an output end of the voltage generating module and used for outputting the stable voltage to the power amplifier through an emitter-follower in a manner of direct current buffer and providing a larger current to the power amplifier. The biasing circuit not only can provide the stable biasing voltage to the power amplifier so as to inhibit the biasing current of the power amplifier from changing greatly with temperature, but also can provide larger biasing current to the power amplifier so as to better meet the requirement of the power amplifier.

Description

technical field [0001] The invention relates to a bias circuit, in particular to a bias circuit of an HBT power amplifier. Background technique [0002] Power amplifiers are widely used in various wireless communication equipment and electronic systems, and their working status is often determined by the bias circuit, so the characteristics of the bias circuit directly affect the performance of the power amplifier, because when the bias current increases with the bias voltage Or when the temperature changes, the working state of the power amplifier will also change accordingly, so the performance of the power amplifier will also change accordingly, especially at low temperature and low pressure, the deterioration of the performance of the power amplifier caused by the bias circuit is particularly obvious. Therefore, a bias circuit with a bias voltage capable of compensating for temperature changes is needed to provide bias to the power amplifier, so as to ensure that the pow...

AI Technical Summary

Problems solved by technology

When the bias voltage changes from 2.75V to 2.95V, when the temperature changes from -30°C to 80°C, the relative change of the collector current Ic1 caused by the bias current of the RF transistor Q1 will reach 50%; use BandGap bandgap The reference source can better solve the temperature characteristics of the paranoid circuit of the traditional power amplifier, but when the GaAs HBT process is used, the bandgap reference cannot be generated

[0004] To sum up, the performance of the power amplifier has a great relationship with its bias voltage, but the traditional power amplifier bias circuit has the problem that the bias current of the power amplifier changes greatly with the bias voltage and temperature, which affects the performance of the power amplifier. And it is inconvenient to adjust the bias voltage. Therefore, it is necessary to propose improved technical means to solve this problem.

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