CMOS RF Power Detector With Feedback Temperature Compensation
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Solution Overview
Problem
Conventional RF power detectors exhibit temperature-dependent output, requiring extensive testing and calibration to correct measurements, which increases production time and costs in wireless communication systems.
Innovation Solution
A temperature-independent CMOS RF power detector circuit is designed using multiple feedback loops and operational amplifiers to negate temperature effects, ensuring the output voltage is proportional to the root-mean-square of the RF input signal regardless of temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RF power detector is used, then the device can detect RF power, but the output voltage changes with temperature requiring extensive testing and calibration
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage of the first section is fed back through a second section to generate a compensating voltage. This feedback loop automatically adjusts for temperature variations, eliminating the need for external calibration while maintaining measurement accuracy across different temperatures.
Solution Approach 2:
The patent introduces an intermediate voltage signal that represents the temperature-dependent characteristics of the first section. This intermediate signal is processed through the second section to generate a compensating voltage that offsets temperature effects, serving as a mediator between the temperature variations and the final measurement output.
2Measurement precision
If temperature correction coefficients are stored and used, then measurement accuracy is maintained, but production time and costs increase
Solution Approach 1:
The patent enables the RF power detector to self-correct for temperature variations through its internal feedback mechanism. The circuit automatically generates compensating voltages based on its own temperature-dependent characteristics, eliminating the need for external calibration procedures and making the device self-sufficient across temperature ranges.
Solution Approach 2:
The patent incorporates temperature compensation circuitry that is inherently built into the detector design from the outset. The second section is configured to automatically generate compensating voltages in anticipation of temperature variations, eliminating the need for post-manufacturing calibration and reducing production time.
3Reliability
If offset coefficients are calculated and stored for each detector, then temperature variations are compensated, but manufacturing complexity and costs increase
Solution Approach 1:
The patent uses a feedback mechanism where the temperature-dependent output of the first section is fed back through the second section to generate an automatic compensating voltage. This eliminates the need for calculating and storing individual offset coefficients for each detector, simplifying manufacturing while maintaining reliable temperature compensation.
Solution Approach 2:
The patent extracts the temperature-dependent characteristics as a separate voltage signal that can be independently processed. By separating the temperature compensation function into a distinct second section, the patent eliminates the need for complex calibration procedures while maintaining compensation reliability.
Data Source
AI summary
A power detector circuit, comprising a first section configured to receive a radio frequency (RF) input signal and to generate a first voltage, wherein the first voltage comprises a voltage proportional to the sum of a mean-square of the RF input signal and a voltage characteristic of the first section, and wherein the first voltage is an input to a third section, a second section configured to generate a second voltage, wherein the second voltage comprises a combination of an output voltage and a voltage proportional to the voltage characteristic of the first section, wherein the output voltage is proportional to a root-mean-square of the RF input signal, the third section configured to generate the output voltage by combining the first voltage and the second voltage, wherein the second section creates a negative feedback loop for the third section and the output voltage generated by the third section is an output of the power detector circuit.