Integrated Sense Resistor Calibration for Precise Current Measurement
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Solution Overview
Problem
Existing current measurement systems in automotive applications face challenges in achieving precise, accurate, and stable current measurements due to temperature and manufacturing variations, which require complex calibration and compensation circuits.
Innovation Solution
A current measurement system with a resistor structure that includes a sense resistor and a calibration resistor formed in the same metal layer, using a calibration circuit to provide a reference voltage, sense amplifiers to measure voltages, and a multiplying ADC to generate digital signals representing the current, with periodic sampling to reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex calibration and compensation circuits are used to achieve precise current measurements, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The calibration resistor and sense resistor are merged into a single resistor structure formed in the same metal layer, allowing both calibration and sensing functions to be integrated in one component. This eliminates the need for separate calibration circuits and reduces overall device complexity while maintaining measurement precision through the integrated design.
Solution Approach 2:
The calibration resistor within the integrated structure serves itself by providing a reference resistance that automatically compensates for temperature and manufacturing variations affecting the sense resistor. This self-compensation mechanism eliminates the need for external calibration circuits and manual adjustment, reducing device complexity while maintaining precision.
2Stability of the object's composition
If continuous calibration current is provided through the calibration resistor, then measurement stability is improved, but power consumption increases
Solution Approach 1:
The calibration current is provided periodically rather than continuously, with the calibration circuit activated at specific intervals to update compensation parameters. This periodic calibration maintains measurement stability by regularly refreshing compensation data while significantly reducing average power consumption compared to continuous calibration current flow.
Solution Approach 2:
The system dynamically adjusts the calibration frequency and timing based on operating conditions, allowing the calibration current to flow only when necessary to maintain accuracy. This dynamic approach optimizes the balance between measurement stability and power consumption by activating calibration only when variations require compensation.
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 system provides precise and stable current measurements by compensating for temperature and manufacturing variations without additional calibration circuits, reducing power consumption by periodic sampling.
Implementation Method 1
calibration circuitry configured to provide a calibration current through the calibration resistor, and sense amplifiers configured to measure respective voltages across each of the calibration resistor and the sense resistor
Implementation Method 2
sense amplifiers configured to measure respective voltages across each of the calibration resistor and the sense resistor
Data Source
AI summary
A current measurement system and a corresponding method are described, where the current measurement system includes a resistor structure having a sense resistor and a calibration resistor where a single metal layer of the resistor structure includes the sense resistor and the calibration resistor, calibration circuitry configured to provide a calibration current through the calibration resistor, and sense amplifiers configured to measure respective voltages across each of the calibration resistor and the sense resistor.