Adaptive bipolar transistor power amplifier linear biasing circuit

Abstract

The invention discloses an adaptive bipolar transistor power amplifier linear biasing circuit, and relates to the technical field of circuits for improving amplifiers to increase the efficiency and improve the linearity. The power supply input end of the biasing circuit is partitioned into four paths through a resistor Rbias0; the first path is connected with the base electrode of a triode QA1; the second path is connected with the collector electrode of a triode QA2; the third path is grounded through a capacitor Cin; the fourth path is connected with the base electrode of a triode QB1; the collector electrodes of the triodes QA1 and QA2 are connected with a VCC (Voltage to Current Converter); the emitter electrode of the triode QA1 is connected with the base electrode of the triode QA2 through a resistor RA1; the emitter electrode of the triode QA2 is grounded; the emitter electrode current of the triode QB1 is output to more than one radio frequency power amplifying tube branch respectively after passing through a resistor Rp. An adaptive biasing linear structure is adopted in the circuit, so that high linearity and high power added efficiency can be effectively realized; meanwhile, a temperature compensating function is realized, the circuit is simplified, the manufacturing difficulty is lowered, and the yield is increased.

Description

technical field [0001] The invention relates to the field of circuit technology for improving amplifiers for improving efficiency and linearity, in particular to an adaptive bipolar transistor power amplifier linear bias circuit. Background technique [0002] RF power amplifier is a very important part of modern communication system, and its performance index plays a central role in the communication system. With the rapid development of third-generation and fourth-generation mobile communication technologies and satellite communications, the technical indicators of RF power amplifiers are becoming more and more stringent, especially power-added efficiency (PAE) and linearity. In communication protocols such as CDMA, appears extremely important. The reason is that high power-added efficiency prolongs talk time and battery life, while high linearity reduces mutual interference between communication channels, improves channel utilization, and widens channel bandwidth. [000...

AI Technical Summary

Problems solved by technology

Power back-off technology is a simple and practical traditional technology that sacrifices power efficiency for high linearity. Although this technology is simple to implement, it greatly reduces the utilization rate of the power amplifier and is not suitable for power amplification systems that require high efficiency; Although the feed-forward technology can improve the linearity of the power amplifier very well, due to the implementation of an open-loop circuit, the changes in the characteristics of all devices over time cannot be compensated, and the circuit structure is complex and the cost is high; the pre-distortion technology also increases the circuit Complexity in exchange for high linearity

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