Cyclic ADC Signal Inversion for Offset Error Cancellation
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Solution Overview
Problem
Cyclic analog to digital converters suffer from error accumulation due to repeated use of the same A/D conversion circuit, leading to deteriorated linearity and increased errors as the number of amplifications increases.
Innovation Solution
Incorporating a cycle processing unit and an output circuit that inverts the digital signal every other cycle, using a D flip-flop and exclusive OR circuit to correct binary signals, and an inverter circuit to input the inverted signal back into the cycle processing unit, thereby reducing offset errors by canceling them out each cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the same A/D conversion circuit is repeatedly used in cyclic conversion, then the circuit size is reduced, but errors such as amplification offset are accumulated and linearity deteriorates
Solution Approach 1:
The patent divides the cyclic conversion process into multiple stages, introducing different gain coefficients (first gain coefficient and second gain coefficient) for different conversion stages. This segmentation allows the system to process the same input signal multiple times with different amplification factors, preventing error accumulation while maintaining compact circuit architecture.
Solution Approach 2:
The patent changes the gain parameter dynamically during cyclic conversion by applying different gain coefficients in different stages. The first gain coefficient is used in initial conversion stages and the second gain coefficient is used in subsequent stages, which prevents the accumulation of amplification offset errors and maintains linearity throughout the conversion process.
2Measurement precision
If the number of amplification cycles is increased to improve conversion precision, then more bits can be obtained, but errors increase as the number of times of amplification increases
Solution Approach 1:
The conversion process is segmented into multiple stages with different gain coefficients. By dividing the amplification process into distinct segments (first gain coefficient for initial stages, second gain coefficient for subsequent stages), the patent prevents cumulative error while achieving high precision through multiple conversion cycles.
Solution Approach 2:
The patent implements a feedback mechanism where the output of each conversion cycle is fed back as input to the next cycle with adjusted gain coefficients. This feedback approach allows the system to iteratively refine the conversion result while compensating for errors through the use of different gain parameters in subsequent cycles.
Data Source
AI summary
Errors in a cyclic analog to digital converter are reduced. An analog to digital converter is a cyclic analog to digital converter for converting an analog input signal into a digital output signal by performing a plurality of times of cycle processing on the analog input signal. A cycle processing unit performs the cycle processing and outputs a digital signal indicating a value of each bit of the digital output signal. An output circuit receives the digital signal output from the cycle processing unit and outputs, as an output signal, a signal obtained by inverting the digital signal every other cycle. A signal input to the cycle processing unit in second and subsequent cycles is generated in the cycle processing in a previous cycle. In the cycle processing, processing for inverting the signal input to the cycle processing is performed.