AD Conversion Calibration for Continuous Bit-Extended Data
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Solution Overview
Problem
Conventional AD conversion techniques face challenges in ensuring data continuity between amplified and direct conversion results due to gain errors and offsets in amplifier circuits, particularly in low-level voltage measurements.
Innovation Solution
A data processing device with a DA converter circuit, an amplifier circuit, and an AD converter circuit, controlled by a calibration circuit, calculates the gain and offset of the amplifier circuit, allowing for bit precision enhancement by canceling gain errors and ensuring data continuity through bit extension processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an amplifier circuit is used to amplify low-level voltage signals before AD conversion, then the bit precision of conversion results is improved, but gain errors and offsets in the amplifier circuit cause discontinuity between amplified and direct conversion results
Solution Approach 1:
The patent applies feedback by measuring the actual gain and offset of the amplifier circuit through calibration and using these measured values to correct the AD conversion results. The control circuit calculates correction values based on the feedback from the measured amplifier characteristics, thereby eliminating the discontinuity between amplified and direct conversion results while maintaining high bit precision
Solution Approach 2:
The patent changes the parameters of the amplifier circuit by dynamically adjusting its gain through digital control. The amplifier circuit's gain is varied according to the input signal level, and the control circuit compensates for the resulting gain errors and offsets by calculating correction values based on pre-measured amplifier characteristics at different gain settings
2Measurement precision
If high-precision amplifier calibration is performed to ensure data continuity, then measurement accuracy is improved, but device complexity and calibration time increase
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing the gain and offset characteristics of the amplifier circuit at various gain settings before actual measurement operations. These calibration values are stored in memory and automatically retrieved during measurement, eliminating the need for complex real-time calibration systems while ensuring data continuity accuracy
Solution Approach 2:
The control circuit performs self-calibration by automatically calculating correction values based on pre-stored amplifier characteristics and the current gain setting. The system serves itself by internally compensating for gain errors and offsets without requiring external calibration equipment or complex calibration procedures
Data Source
AI summary
In AD conversion of a voltage, data continuity is ensured between the results of conversion after amplification and of direct conversion without amplification. In AD conversion operation, an analog signal output from a DA converter circuit is directly converted by an AD converter circuit, and the analog signal is converted after amplification with an expected gain of 2′. Based on resultant data, a gain of an amplifier circuit and an offset thereof are calculated. An analog signal to be enhanced in bit precision is amplified by the amplifier circuit and converted by the AD converter circuit, the offset is subtracted from the resultant conversion, and the result is multiplied by a ratio of the expected gain to the calculated gain to cancel gain error. Based on data with gain error canceled, acquisition of bit-extended conversion result data is performed to ensure continuity between data having different degrees of bit precision.