RMS Power Detector Signal-Independent Dynamics
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Solution Overview
Problem
Existing RMS power detection architectures in mobile devices and wireless systems face challenges with signal-dependent dynamics and loop gain variability, which affect accuracy and stability, especially with varying input signal levels.
Innovation Solution
The implementation of an RMS power detector with signal-independent dynamics, utilizing voltage-to-current amplifiers, a multiplier cell, and controlled amplifiers to maintain a constant loop gain independent of the input signal level, achieved through the use of controlled amplifiers that adjust gain based on the output signal, allowing for accurate and temperature-stable power detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional feedback architectures with multipliers and non-linear elements are used, then RMS power detection accuracy is improved, but loop gain becomes signal-dependent causing dynamic performance degradation
Solution Approach 1:
The patent transforms the conventional voltage feedback architecture into a current feedback architecture. By changing the feedback parameter from voltage to current and using controlled current mirrors instead of multipliers, the loop gain becomes independent of the input signal level. This parameter change resolves the contradiction by maintaining accuracy through feedback while eliminating signal-dependent dynamics.
Solution Approach 2:
The patent replaces the conventional multiplier-based non-linear feedback mechanism with a current mirror-based linear feedback mechanism. The current mirrors replicate currents proportionally without the signal-level dependent behavior of multipliers, thus maintaining measurement accuracy while achieving signal-independent loop gain.
2Stability of the object's composition
If conventional RMS detection architectures are used, then temperature-independent detection is achieved, but dynamic performance varies with input signal level
Solution Approach 1:
The patent changes the feedback domain from voltage to current and uses controlled current sources that are independent of the input signal amplitude. This allows the architecture to maintain temperature independence through proper biasing while achieving consistent dynamic performance across different signal levels by eliminating the signal-dependent loop gain of conventional designs.
3Measurement precision
If feedback paths with non-linear elements are implemented, then accurate RMS power measurement is achieved, but the system complexity increases
Solution Approach 1:
The patent replaces complex non-linear elements (multipliers, square-law devices) with simpler current mirror circuits and controlled current sources. The current mirrors provide the necessary feedback functionality through linear current replication, eliminating the need for complex non-linear components while maintaining RMS measurement accuracy.
Solution Approach 2:
The patent uses current mirrors to create copies of reference currents and feedback currents. These current copies provide the necessary feedback signals without requiring complex processing circuits, thus reducing overall system complexity while maintaining measurement precision.
Data Source
AI summary
A circuit is configured to receive an input signal and to produce an output signal measuring a power of the input signal. The circuit includes a multiplier cell configured to multiply first and second signals, where each of the first and second signals includes a component related to the input signal and a component related to the output signal. The circuit also includes a controlled amplifier configured to amplify an intermediate signal produced by the multiplier cell, where an amplification provided by the controlled amplifier is a function of the output signal. The circuit could further include at least one first converting amplifier configured to generate the component related to the input signal and at least one second converting amplifier configured to generate the component related to the output signal. Transconductances of the converting amplifiers could be selected to configure the circuit as a linear or logarithmic RMS power detector.