A/D Converter Reference Potential Isolation for Accurate Sampling
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Solution Overview
Problem
Independent operation of sampler and D/A converter in A/D converters can lead to reduced calculation accuracy due to potential fluctuations when switches are turned off at slightly different times, affecting overall performance.
Innovation Solution
An A/D converter configuration with a reference potential generation circuit that independently sets and maintains two reference potentials, ensuring no interference between the sampler and D/A converter, even when switches are turned off at different times, using multiple switches and a control circuit to manage these potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sampler and D/A converter are independently connected to the integrator, then the A/D converter can execute sample/hold and DAC operations at independent timings, but potential fluctuations occur when switches are turned off at slightly different times, reducing calculation accuracy
Solution Approach 1:
The reference potential supply is segmented into two independent circuits: one reference potential supply circuit dedicated to the sampler and another dedicated to the D/A converter. This segmentation prevents the reference potential from being affected by the switching operations of either component, thereby maintaining calculation accuracy while preserving independent operation capability.
Solution Approach 2:
A dedicated reference potential supply circuit acts as an intermediary between the power source and the sampler/D-A converter switches. This intermediary stabilizes the reference potential by isolating it from the switching operations, preventing potential fluctuations that would otherwise occur when switches are turned off at different times.
2Device complexity
If a single reference potential is shared between the sampler and D/A converter, then the circuit structure is simplified, but potential fluctuations occur when switches are turned off at different times, affecting overall performance
Solution Approach 1:
The single shared reference potential circuit is segmented into two independent reference potential supply circuits, each dedicated to either the sampler or the D/A converter. This segmentation eliminates the performance degradation caused by switching interference while maintaining relatively simple circuit architecture.
3Device complexity
If the sampler and D/A converter share a common reference potential, then the circuit configuration is simpler, but calculation accuracy is reduced due to potential fluctuations during switch operations
Solution Approach 1:
The common reference potential is segmented into separate reference potential supply circuits for the sampler and D/A converter. This segmentation prevents switching operations from causing potential fluctuations that would affect calculation accuracy, while keeping the overall circuit configuration relatively simple.
Solution Approach 2:
Separate reference potential supply circuits act as intermediaries that isolate the reference potential from the switching operations of the sampler and D/A converter. This intermediary structure prevents the harmful effects of simultaneous switch-off on calculation accuracy.
Data Source
AI summary
An A/D converter includes: a sampler that includes a sampling capacitor and samples an input signal; a D/A converter that selectively outputs an analog voltage; an integrator that integrates an input from the sampler and an input from the D/A converter; Multiple switches that include a first switch independently connecting the sampler to the integrator, a second switch independently connecting the D/A converter to the integrator, a third switch, and, a fourth switch, a quantizer that quantizes an output of the integrator; a control circuit that outputs a digital value based on an output of the quantizer, and a reference potential generation circuit that provides a second reference potential to an integrator side of the sampler through the third switch and provides a first reference potential to the integrator side of the D/A converter through the fourth switch.