Integrated power detector with temperature compensation for fully-closed loop control
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Solution Overview
Problem
Power detectors connected to intermediate stages of power amplifiers fail to accurately measure actual output power due to temperature variations and antenna mismatch, leading to inaccurate power readings.
Innovation Solution
A power detector circuit with temperature compensation, comprising a detection circuit that generates a power control voltage to offset temperature characteristics, allowing for accurate monitoring of RF signal power and adjusting the bias signals to maintain consistent output power across temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power detector input is connected to an intermediate stage of the power amplifier, then the influence from antenna mismatch is avoided, but the detected power does not represent the actual output power of the power amplifier
Solution Approach 1:
The patent implements a feedback mechanism where the power detector monitors the intermediate stage power and feeds back control signals to adjust the power amplifier's operating parameters. This closed-loop feedback system compensates for the detection inaccuracy by continuously adjusting the amplifier to maintain the desired actual output power, even though the detector is not directly measuring the final output stage.
2Loss of information
If the power detector monitors the output power directly, then the actual output power is measured, but the readings are affected by antenna mismatch
Solution Approach 1:
The patent introduces an intermediary approach by placing the power detector at an intermediate stage rather than directly at the output. This intermediate detection point serves as a mediator that avoids the direct influence of antenna mismatch while still providing power level information that can be used for control, bridging the gap between direct measurement and mismatch-free detection.
Solution Approach 2:
The system uses feedback control where the intermediate stage detection results are fed back to adjust the power amplifier parameters, compensating for the fact that intermediate power does not directly represent output power. The feedback loop continuously corrects the amplifier operation to maintain accurate actual output power despite the indirect measurement approach.
3Measurement precision
If temperature compensation is added to the power detector, then temperature variations are compensated and power reading accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent implements temperature compensation by detecting temperature variations and dynamically adjusting detector circuit parameters (such as bias voltages or reference levels) to compensate for temperature effects. This parameter change approach allows the detector to maintain accurate power readings across different temperatures without requiring a completely redundant measurement system.
Solution Approach 2:
The temperature compensation function is merged with the existing power detection circuit rather than being implemented as a separate standalone system. The compensation mechanism is integrated into the detector's signal processing path, combining temperature sensing and power measurement functions in a unified circuit architecture to minimize overall complexity.
Data Source
AI summary
An amplifier circuit comprises a detection power input circuit for receiving an RF signal, and a bias circuit that includes an output for generating a bias signal in response to a reference control voltage. The power detector further comprises a detection circuit for generating a power control voltage having a voltage characteristic that offsets temperature characteristics of the received RF signal. The amplifier circuit further comprises a power amplifier coupled to the bias circuit. The power amplifier includes a driver stage providing the RF signal. The detection circuit compensates temperature variation of the inputted detection voltage of the received RF signal.