Current Sensor Channel Offset Calibration via Digital Register Storage
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Solution Overview
Problem
Current sensor channels face challenges in accurately correcting analog offsets due to variations in component offsets and environmental factors, leading to unsatisfactory results and significant resource usage in existing correction methods.
Innovation Solution
A method and system for measuring and storing channel offsets in digital form, using a calibration module to adjust digital output data based on stored offset values, allowing for periodic self-calibration to adapt to changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If trimming circuits are added to correct channel offset, then offset correction capability is improved, but chip area and calibration time increase significantly
Solution Approach 1:
The patent creates a virtual copy of the offset correction function by measuring the offset through digital output data and storing it in a register, then using this stored value to calibrate subsequent measurements. This digital copying approach replaces the need for physical trimming circuits, achieving offset correction without additional chip area.
Solution Approach 2:
The patent replaces the mechanical/physical trimming circuit approach with a digital measurement and storage system. Instead of using physical components to trim offsets, the system measures the offset through the existing ADC and stores the digital value for later correction, substituting physical circuitry with digital processing.
2Measurement precision
If trimming circuits are added to correct channel offset, then offset correction capability is improved, but calibration time in factory increases
Solution Approach 1:
The patent performs offset measurement and storage as a preliminary action during device initialization or manufacturing. The offset value is measured once and stored in a register for future use, eliminating the need for time-consuming calibration procedures during factory testing or subsequent operations.
Solution Approach 2:
The system performs self-calibration by automatically measuring its own offset through the existing ADC and storing the value in its own register. This self-service capability eliminates the need for external calibration equipment and procedures, significantly reducing factory calibration time.
3Measurement precision
If additional SH circuit is added to sample and remove TIA offset, then offset correction is improved, but device complexity increases
Solution Approach 1:
The patent merges the offset measurement function with the existing ADC and register infrastructure. Instead of adding separate SH circuits for offset sampling, the system uses the existing ADC to convert the offset voltage to digital form and stores it in an available register, combining multiple functions into existing components.
Solution Approach 2:
The existing ADC and register components are made multi-functional by using them for both normal signal conversion and offset measurement. The ADC converts both signal voltages and offset voltages to digital form, while registers store both signal data and offset calibration values, eliminating the need for dedicated offset correction circuits.
Data Source
AI summary
Analog channel calibration methods, devices and systems are disclosed. One embodiment of the present invention pertains to a method for calibrating a channel offset of a current sensor which comprises measuring a channel offset native to a current sensor channel. The method also comprises storing the channel offset native to the current sensor channel to a register associated with the current sensor channel as a value. Additionally, the method comprises calibrating an output signal generated in response to an input signal to the current sensor channel based on the value.