Adaptive Slope ADC Using MSB Pre-Detection for Faster Conversion
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Solution Overview
Problem
Slope analog-to-digital converters (ADCs) face limitations in speed and resolution due to the need to loop through all possible signal levels for high-resolution conversions, resulting in slow conversion rates and limited application in systems requiring high sampling rates or resolutions.
Innovation Solution
A slope ADC design that determines the most significant bit of the analog input signal during an initial period, allowing the comparator to adaptively compare the sampled value with a slope signal during the conversion period, reducing the range of the slope signal and enabling faster conversion by potentially halving the conversion time or increasing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the slope ADC loops through all possible signal levels for high-resolution conversion, then the resolution is improved, but the conversion speed deteriorates
Solution Approach 1:
The most significant bit is determined during the initial period before the conversion period begins. This preliminary determination reduces the range of the slope signal that needs to be traversed during conversion, effectively halving the conversion time while maintaining full resolution capability.
2Speed
If the slope ADC uses a continuous-time comparator that is continuously turned on, then the conversion speed is improved, but the power consumption increases
Solution Approach 1:
The comparator is operated periodically rather than continuously. It is turned on during the initial period to determine the most significant bit and during the conversion period, then turned off during other periods. This periodic operation maintains high sampling speed while significantly reducing average power consumption.
Data Source
AI summary
A slope analog-to-digital converter, ADC, comprises: an input unit comprising a sampling capacitor, wherein the input unit is configured to during an initial period obtain a sampled value of an analog input signal and, during a conversion period, hold the sampled value across the sampling capacitor; and a comparator configured to determine a most significant bit of the analog input signal during the initial period; wherein the ADC during the conversion period is configured to receive a slope signal and to be adapted based on the determined most significant bit such that the comparator is further configured to adaptively compare the sampled value and the slope signal for converting the sampled value to a digital representation.