ADC Reference Bias Calibration for Low-Power Precision Conversion
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Solution Overview
Problem
Analog to digital converters require continuous power to maintain accurate digitized outputs, as precise external voltage or current references cannot be quickly turned on and off, leading to high power consumption during operation.
Innovation Solution
A system and method that utilize an external low noise supply as a reference bias, calibrated and corrected in the digital domain, allowing the external reference standard to be turned off during operation, thereby saving power. This involves determining a correction factor during calibration mode and using it to adjust the digital output, eliminating the need for reciprocal calculations and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external precision reference standard is used for accurate ADC conversion, then measurement precision is improved, but power consumption increases because the reference cannot be turned off
Solution Approach 1:
The system performs calibration in advance to determine correction factors that compensate for reference voltage errors. During normal operation, the expensive precision reference can be turned off and a lower-power reference used, while the pre-calculated correction factors maintain accuracy. This resolves the contradiction by preparing the compensation data beforehand rather than requiring continuous precision reference operation.
Solution Approach 2:
The patent creates a digital copy or model of the reference voltage error characteristics through calibration measurements. This digital representation (correction factors) allows the system to compensate for reference errors without continuously operating the precision reference hardware, thereby reducing power consumption while maintaining measurement accuracy.
2Reliability
If the precision reference is kept on continuously for accurate conversion, then reliability is improved, but energy loss increases
Solution Approach 1:
The system performs calibration in advance to determine correction factors that compensate for reference voltage errors. During normal operation, the expensive precision reference can be turned off and a lower-power reference used, while the pre-calculated correction factors maintain accuracy. This resolves the contradiction by preparing the compensation data beforehand rather than requiring continuous precision reference operation.
3Measurement precision
If traditional calibration methods are used requiring reciprocal calculations, then measurement precision is maintained, but device complexity increases
Solution Approach 1:
The patent replaces complex analog calibration circuitry with digital processing. Instead of using analog adders and amplifiers to compute reciprocal calibration factors, the system uses a digital signal processor to perform the calculations. This substitution of digital for analog complexity reduces the number of analog components while maintaining calibration accuracy.
Solution Approach 2:
The patent changes the domain of calibration computation from analog to digital. By performing reciprocal calculations in the digital domain rather than requiring complex analog circuitry, the system maintains measurement precision while significantly reducing device complexity. The correction factors are computed digitally and stored for use during conversion operations.
Data Source
AI summary
An analog-to-digital (ADC) converter system and method of using the system that can be used in low power situations. The converter can periodically or recurrently turn off a reference standard in order to conserve power and instead using a stable supply source as a reference voltage. A precise conversion for signal from the analog to the digital domain while maintaining a low quiescent current.