Adaptive Bipolar Transistor Power Amplifier Linear Bias Circuit

Abstract

The invention discloses a linear bias circuit of an adaptive bipolar transistor power amplifier, and relates to the technical field of circuits for improving amplifiers for improving efficiency and linearity. The power input terminal of the bias circuit is divided into four circuits through the resistor Rbias0, the first circuit is connected to the base of the transistor QA1, the second circuit is connected to the collector of the transistor QA2, the third channel is grounded through the capacitor Cin, and the fourth channel is connected to the transistor QA1 The base of QB1 is connected; the collectors of transistor QA1 and transistor QB1 are connected to VCC, the emitter of transistor QA1 is connected to the base of transistor QA2 through resistor RA1, the emitter of transistor QA2 is grounded, and the emitter current of transistor QB1 passes through resistor Rp respectively Output to more than one RF power amplifier tube branch. The circuit adopts an adaptive bias linear structure, which can effectively realize high linearity and high power-added efficiency, and at the same time has the function of temperature compensation, and simplifies the circuit, reduces the difficulty of production, and improves the yield.

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, which 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 with high efficiency requirements; 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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