ADC Reference Voltage Switching for Wide-Range Current Measurement
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Solution Overview
Problem
Existing ADC systems struggle to accurately measure both small and large signals without increasing cost and complexity by requiring multiple ADCs or signal conditioning circuitry.
Innovation Solution
Implementing a dynamic sensitivity adjustment method using a single ADC with multiple reference voltages and a microprocessor to switch between them based on signal thresholds, allowing accurate measurement of both high and low outlet currents without additional circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple ADCs are used to measure both small and large signals, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies dynamics by making the ADC reference voltage adjustable rather than fixed. The system dynamically switches between a first reference voltage (for small signals) and a second reference voltage (for large signals) based on the magnitude of the input signal. This dynamic adjustment allows a single ADC to adapt its sensitivity to match the signal being measured, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent changes the reference voltage parameter of the ADC based on signal magnitude. When the input signal exceeds a threshold, the system switches from a first reference voltage to a second reference voltage. This parameter change allows the same ADC hardware to achieve different measurement ranges and precision levels, eliminating the need for multiple ADCs while maintaining measurement accuracy across varying signal levels.
2Measurement precision
If signal conditioning circuitry with amplifiers is used to measure small signals, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the signal conditioning function from separate amplifier circuitry and integrates it into the ADC's reference voltage selection mechanism. Instead of using external amplifiers to boost small signals, the system uses a first reference voltage that provides high sensitivity directly at the ADC input. This eliminates the need for additional amplifier components while achieving the same effect of enhancing small signal measurement capability.
Solution Approach 2:
The ADC is designed to perform multiple functions by switching between different reference voltages. The same ADC hardware can measure both small signals (using the first reference voltage) and large signals (using the second reference voltage) without requiring separate dedicated circuits for each function. This multi-functionality reduces device complexity while maintaining measurement precision across different signal levels.
3Device complexity
If a single ADC is used for both small and large signals, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The system dynamically adjusts the ADC's reference voltage based on the magnitude of the input signal. A control circuit monitors the signal level and switches between a first reference voltage (optimized for small signals) and a second reference voltage (optimized for large signals). This dynamic adaptation allows the single ADC to maintain high measurement precision across its entire operating range, resolving the contradiction between using a simple single-ADC architecture and achieving high measurement precision.
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AI summary
Systems and methods of measuring dynamic signals for power distribution units. In one embodiment, a power distribution unit (PDU) includes an analog to digital converter (ADC) including a plurality of channels, each channel corresponding to a respective outlet of a plurality of outlets of the PDU. The PDU further includes a microprocessor coupled to the ADC and configured to measure a scale of a signal output from a first channel of the ADC, compare the scale of the signal to a sensitivity threshold, and select, for a first outlet corresponding to the first channel, a reference voltage of a plurality of reference voltages for input to the ADC based on a result of comparing. Various embodiments allow using an ADC to measure low level outlet currents of less than around 300mA in addition to high level currents such as around 20A.