Multi-Branch Current Measurement for Wide Dynamic Range
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Solution Overview
Problem
Conventional electronic circuits struggle to measure analog electrical signals with wide amplitude ranges due to limitations in dynamic range, leading to measurement errors and noise issues, particularly when dealing with high-dynamic-range signals from sources like photodiodes.
Innovation Solution
The proposed solution involves a measurement circuit with multiple branches, each with different impedances, connected by a nonlinear circuit element, which adjusts signal gain based on the input signal's magnitude, using a combination of transimpedance amplifiers and analog-to-digital converters to accurately quantify the signal across varying amplitudes, thereby reducing noise and maintaining precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional precision ADC circuit is used to measure an electrical signal, then measurement precision is improved, but the circuit cannot handle signals with wide amplitude range
Solution Approach 1:
The measurement circuit is divided into multiple parallel circuit branches (first branch with first ADC, second branch with second ADC), each optimized for different signal amplitude ranges. The nonlinear circuit element divides the input current signal between branches based on magnitude, allowing each branch to specialize in measuring specific amplitude ranges with high precision while collectively handling wide dynamic ranges.
2Adaptability or versatility
If the signal amplitude range is increased to handle wide dynamic range signals, then adaptability is improved, but measurement precision deteriorates due to noise and errors
Solution Approach 1:
Each circuit branch is designed with specific local characteristics optimized for its intended operating range. The first branch includes a first ADC optimized for lower amplitude signals, while the second branch includes a second ADC optimized for higher amplitude signals. This local optimization ensures high measurement precision within each branch's operational range while collectively covering the full dynamic range.
Solution Approach 2:
The circuit dynamically adapts its measurement path based on signal magnitude. The nonlinear circuit element automatically directs appropriate portions of the input current to different branches based on real-time signal conditions. This dynamic allocation ensures that the measurement system always operates in the optimal precision range for the current signal level.
3Adaptability or versatility
If multiple circuit branches with different impedances are used to extend dynamic range, then adaptability is improved, but device complexity increases
Solution Approach 1:
The nonlinear circuit element serves multiple functions simultaneously: it acts as a current splitter, a signal router, and a gain controller. By placing it at the input stage, it automatically directs signals to appropriate measurement branches based on amplitude, eliminating the need for additional switching mechanisms or control circuitry. This multi-functionality extends dynamic range while minimizing added complexity.
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 approach effectively extends the dynamic range of signal measurement, reduces noise, and maintains accuracy by selectively summing outputs from different branches based on the signal's magnitude, allowing for precise quantization of high-dynamic-range signals without relying on exact nonlinearity characteristics.
Implementation Method 1
a nonlinear circuit element coupling the first circuit branch to the second circuit branch
Data Source
AI summary
A measurement circuit comprises an input terminal to receive a current signal, a first circuit branch coupled to the first terminal and including one or more circuit elements to receive a portion of the current signal, a second circuit branch coupled to the first terminal and including one or more additional circuit elements to receive another portion of the current signal, a nonlinear circuit element coupling the first circuit branch to the second circuit branch, and a quantization circuit configured to produce an input current measurement of current in the first and second circuit branches, and to include current in the second circuit branch in the input current measurement according to a magnitude of the input current signal.