Multi-ADC Ranging Circuit for Glitch-Free Gain Transitions
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Solution Overview
Problem
Measurement systems face glitches and errors due to changes in signal ranges, leading to discontinuities and noise, as existing technologies lack flexibility in configuring amplifiers and analog-to-digital converters (ADCs) for varying signal ranges, causing transient signals and amplifier mismatches.
Innovation Solution
A measurement system with a gain chain and range selector that dynamically configures gains for multiple ADCs, using a mixer to combine outputs from different ADCs and switch banks to select appropriate gain stages, allowing seamless ranging by maintaining both ADCs online during transitions and applying weighted mixing of outputs to reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If amplifier stages are switched on and off to configure gain for different signal ranges, then flexibility in configuring gain is improved, but glitching and discontinuity in the measurement occur during transitions
Solution Approach 1:
The system performs preliminary action by keeping both amplifier chains active and configured for their respective ranges before a transition is needed. The second amplifier chain is warmed up and ready in advance, so when a range transition occurs, the switch between chains is seamless without glitches or discontinuities in the measurement signal.
2Measurement precision
If selective amplification is used to address errors in different signal ranges, then measurement precision is improved, but amplifier noise, offsets, gain errors, and phase mismatches are introduced
Solution Approach 1:
A mixer serves as an intermediary component that combines the outputs of two ADCs with different amplifier chains. The mixer allows the system to select from multiple amplified signals and combine them appropriately, reducing the impact of individual amplifier errors and noise while maintaining measurement precision across different signal ranges.
3Measurement precision
If large gain is applied to small signals to increase resolution, then measurement precision is improved, but ADC saturation and signal distortion occur when signals become larger
Solution Approach 1:
The measurement system is segmented into two separate amplifier chains, each optimized for different signal ranges. The first chain uses large gain for small signals to achieve high resolution, while the second chain uses smaller gain for larger signals to prevent ADC saturation. A range selector and mixer enable seamless switching between the two segmented paths based on signal amplitude.
Data Source
AI summary
A measurement system includes a gain chain configured to amplify an analog input signal; a range selector configured to select a gain between the analog input signal and a plurality of analog-to-digital converter (ADC) outputs from a plurality of ADCs, wherein each ADC output has a path, and a gain of each output path is made up of a plurality of gain stages in the gain chain; and a mixer configured to combine the plurality of ADC outputs into a single mixed output.