Absolute Voltage Measurement Circuit Using Dual Temperature References
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Solution Overview
Problem
Existing analog-to-digital converter (ADC) circuits face challenges in accurately measuring absolute voltage signals due to sensitivity to mechanical stress and the need for precise reference voltage stability, which is often compromised by packaging and soldering processes.
Innovation Solution
A method and circuit that utilize a digital domain approach by applying a positive and negative temperature coefficient reference signal to an ADC, allowing for absolute voltage measurement with reduced sensitivity to mechanical stress and eliminating the reliance on long-term stability of the reference voltage, using a mathematical function of digital reference values and the raw signal value to calculate the absolute voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bandgap voltage reference is used to ensure long-term stability, then reference voltage precision is improved, but sensitivity to mechanical stress from packaging and soldering increases
Solution Approach 1:
The patent replaces the mechanical/analog bandgap voltage reference system with a digital measurement system. Instead of relying on physical bandgap circuits that are sensitive to mechanical stress, the invention uses an ADC to digitize voltage references and performs calculations in the digital domain, eliminating the harmful mechanical stress sensitivity while maintaining measurement accuracy
Solution Approach 2:
The patent changes the operating domain from analog to digital. By converting voltage measurements to digital values and performing reference calculations digitally, the system achieves immunity to mechanical stress while maintaining precision. The measurement parameters are transformed from continuous analog voltages to discrete digital values that can be processed without mechanical sensitivity
2Measurement precision
If a precise reference voltage is used for accurate ADC conversion, then measurement precision is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent merges the reference voltage generation and measurement functions into a single integrated digital processing routine. Instead of separate analog reference circuits and measurement circuits, the invention combines both functions into one ADC-based digital measurement system, reducing component count while maintaining precision
Solution Approach 2:
The system uses itself to measure its own reference voltages. The same ADC that measures the target voltage also measures the reference voltages, and the processor performs all calculations autonomously. This self-service approach eliminates the need for separate precision reference circuits, reducing device complexity while maintaining measurement accuracy
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
The solution significantly reduces mechanical stress sensitivity by a factor of 2.0 or more compared to classical bandgap voltage-based ADCs, achieving accurate absolute voltage measurements with minimal impact from reference voltage drift and mechanical stress, and requires fewer components and less space on a semiconductor substrate.
Implementation Method 1
applying a first reference signal having a positive temperature coefficient to the input port of the at least one A/D convertor while applying a reference voltage to the reference port of the at least one A/D convertor
Data Source
AI summary
A method and a circuit for measuring an absolute voltage signal, such that the circuit comprises: an A/D convertor, and a controller adapted for: a) obtaining a first digital reference value for a first reference signal having a positive temperature coefficient; b) obtaining a second digital reference value for a second reference signal having a negative temperature coefficient; c) obtaining a raw digital signal value for the signal to be measured, while applying a same reference voltage for step a) to c); and d) calculating the absolute voltage value in the digital domain using a mathematical function of the first and second digital reference value, and the raw digital signal value.