RF Power Amplifier Feedback Biasing for Stable Gain and Output
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Solution Overview
Problem
Radio frequency power amplifiers in wireless communication systems experience gain and output power variations due to process deviations and temperature fluctuations, necessitating feedback control to stabilize operating states.
Innovation Solution
A radio frequency power amplifier with multiple stages of amplifier circuits, incorporating power detection and current detection feedback circuits to adjust quiescent operating currents and gains based on output power and current variations, ensuring stable gain and output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If feedback control is implemented to stabilize gain and output power, then stability of gain and output power is improved, but device complexity increases due to additional detection feedback circuits
Solution Approach 1:
The patent implements feedback control by detecting the output power through detection circuits and adjusting the quiescent operating current of the power amplifier accordingly. The detection feedback circuit monitors the actual output power and feeds this information back to the bias control circuit, which then adjusts the operating point to maintain stable gain and output power despite process deviations and temperature variations.
Solution Approach 2:
The power amplifier system performs self-adjustment through the feedback mechanism. The detection circuits automatically monitor the output power and the bias control circuit automatically adjusts the quiescent operating current without external intervention. This self-service capability enables the system to compensate for process variations and temperature drift autonomously.
2Stability of the object's composition
If quiescent operating current is increased to maintain stable output power, then output power stability is improved, but power consumption increases
Solution Approach 1:
The patent employs dynamic adjustment of the quiescent operating current based on real-time detection of output power. Rather than using a fixed high current to ensure stability, the system dynamically modifies the operating current according to actual operating conditions, process deviations, and temperature variations. This dynamic approach maintains output power stability while optimizing power consumption by avoiding unnecessary current levels.
Data Source
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AI summary
Disclosed in the present invention are a radio frequency power amplifier based on power detection feedback, a chip, and a communication terminal. The radio frequency power amplifier comprises multiple stages of amplifier circuits and at least one power detection feedback circuit; the input end of the power detection feedback circuit is connected to the output end of a current stage of amplifier circuit, and the output end of the power detection feedback circuit is connected to the input ends of the current stage of amplifier circuit and at least one stage of amplifier circuit located prior to the current stage of amplifier circuit. The power detection feedback circuit generates, according to the detected output power of the current stage of amplifier circuit, a control voltage varying inversely with the output power, so that the power detection feedback circuit outputs current varying positively with the control voltage. The quiescent operating current of the current stage of amplifier circuit and at least one stage of amplifier circuit located prior to the current stage of amplifier circuit is controlled by means of the current, so that the radio frequency power amplifier operates in a state in which the gain and the output power are stable.