RF Power Detector Using Split Rails for Wide Dynamic Range
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Solution Overview
Problem
Radio frequency (RF) signal power detectors in RF transmitters require significant current from power rails to generate power-indicating signals, leading to high current consumption and potential redesign needs for power management circuits due to large dynamic power ranges in RF signals.
Innovation Solution
The implementation of a radio frequency (RF) signal power detector that includes a first current source generating a current based on the power level of an RF signal, a transimpedance amplifier (TIA) to convert this current into a voltage, and a second current source generating a current related to the first current, with both current sources coupled in series between upper and lower voltage rails, allowing for reduced current demand from the primary voltage rail through bleed current from an additional rail.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single voltage rail supplies current to the power detector, then the power detector can generate power-indicating signals, but the current consumption from that voltage rail becomes excessively high
Solution Approach 1:
The power detector is divided into two separate current paths: a first current path from a first voltage rail that provides a baseline current, and a second current path from a second voltage rail that provides an additional current. This segmentation allows the total current requirement to be distributed across multiple voltage rails, reducing the burden on any single rail while maintaining the power detection function.
Solution Approach 2:
A current combiner circuit acts as an intermediary that receives currents from two different voltage rails and combines them into a single combined current that flows through the power detection circuitry. This intermediary structure enables the power detector to draw current from multiple sources without requiring redesign of the power management system.
2Reliability
If the voltage rail provides large dynamic power range, then the RF signal detection capability is improved, but the power management circuit requires redesign
Solution Approach 1:
The power detection function is segmented across multiple voltage rails with different current capabilities. The first voltage rail provides a stable baseline current suitable for low-power detection, while the second voltage rail provides additional current for high-power detection. This segmentation allows existing power management circuits to continue operating without redesign.
Solution Approach 2:
The power detector is designed to universally accept currents from multiple voltage rails with different characteristics. The current combiner circuit and adjustable gain amplifier can handle a wide range of current inputs, making the detector compatible with various existing power management configurations without requiring system-wide redesign.
3Use of energy by moving object
If multiple current sources are used to reduce primary rail current demand, then the current capability requirement of the primary voltage rail is reduced, but the device complexity increases
Solution Approach 1:
A current combiner circuit serves as an intermediary that simplifies the integration of multiple current sources. Instead of requiring complex parallel circuitry from multiple voltage rails, the combiner provides a straightforward summation point that reduces design complexity while achieving the goal of distributing current demand across multiple rails.
Solution Approach 2:
The power detector incorporates feedback mechanisms through the transimpedance amplifier and adjustable gain amplifier that automatically balance the currents from multiple sources. This feedback control simplifies the overall circuit design by eliminating the need for manual current matching and complex balancing networks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces the current capability requirement of the primary voltage rail, enabling efficient power-indicating voltage generation across a large dynamic range without necessitating redesign of existing power management circuits.
Implementation Method 1
a transimpedance amplifier (TIA) configured to generate a first voltage based on the first current
Data Source
AI summary
An aspect relates to an apparatus including a radio frequency (RF) signal power detector. The RF signal power detector includes a first current source configured to generate a first current based on a power level of a first RF signal; a transimpedance amplifier (TIA) configured to generate a first voltage based on the first current, wherein the TIA is coupled between a first upper voltage rail and a lower voltage rail; and a second current source configured to generate a second current related to the first current, wherein the first and second current sources are coupled in series between a second upper voltage rail and the lower voltage rail.