Flash ADC Time-Domain Interpolation for High-Resolution Conversion
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Solution Overview
Problem
Conventional flash analog-to-digital converters (ADCs) face challenges with exponential growth in circuit size, power consumption, and capacitive loading as binary resolution increases, making them unsuitable for high-speed applications, and existing solutions either reduce conversion speed or increase conversion time.
Innovation Solution
A time domain interpolation scheme for flash ADCs is introduced, utilizing voltage comparators with clocked outputs and arrival time comparators to interpolate intermediate voltage levels, reducing the number of comparators required and improving conversion speed while maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the binary resolution of a flash ADC is increased, then the conversion accuracy is improved, but the circuit size, power consumption, and capacitive loading increase exponentially
Solution Approach 1:
The patent divides the flash ADC into multiple sub-ADCs, each handling a portion of the voltage range. Instead of using one large flash ADC with 2^N-1 comparators for N-bit resolution, the system uses multiple smaller flash ADCs that process segments of the input range, significantly reducing the number of comparators required in each unit while maintaining overall high conversion accuracy through parallel operation and result combination.
2Measurement precision
If the binary resolution of a flash ADC is increased, then the conversion accuracy is improved, but the power consumption increases exponentially
Solution Approach 1:
By segmenting the high-resolution conversion task across multiple lower-resolution flash ADCs, the power consumption is distributed and reduced. Each sub-ADC consumes less power than a single high-resolution flash ADC would require, and the parallel architecture allows efficient power management while achieving the same overall conversion accuracy.
3Measurement precision
If the binary resolution of a flash ADC is increased, then the conversion accuracy is improved, but the capacitive loading increases exponentially
Solution Approach 1:
The patent reduces capacitive loading by dividing the comparator array into multiple smaller groups within each sub-ADC. This segmentation decreases the total capacitance that the reference voltage sources and input signal must drive, as each sub-ADC handles only a portion of the total voltage range, thereby reducing the exponential capacitive loading problem associated with high-resolution flash ADCs.
4Device complexity
If existing solutions are used to reduce circuit size, then the device complexity is reduced, but the conversion speed decreases
Solution Approach 1:
The patent maintains high conversion speed by using parallel processing architecture where multiple flash ADCs operate simultaneously on different voltage segments. This parallel segmentation approach avoids the speed penalty of sequential processing methods while achieving reduced circuit complexity compared to a single high-resolution flash ADC.
5Device complexity
If existing solutions are used to reduce circuit size, then the device complexity is reduced, but the conversion time increases
Solution Approach 1:
The patent eliminates conversion time delays by implementing parallel processing where all sub-ADCs convert their respective voltage segments simultaneously in a single conversion cycle. This parallel segmented architecture avoids the multi-step sequential conversion processes that increase conversion time, maintaining fast conversion while reducing circuit size.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for faster and more accurate analog-to-digital conversion with reduced circuit size and power consumption, making it suitable for high-speed applications by effectively interpolating intermediate voltage levels without sacrificing resolution.
Implementation Method 1
voltage comparators with clocked outputs and arrival time comparators to interpolate intermediate voltage levels
Data Source
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AI summary
An analog-to-digital converter circuit comprises a first voltage comparator coupled to a first reference voltage and a signal voltage, the first voltage comparator having first negative and first positive outputs for outputting a comparison of the first reference voltage with the signal voltage; a second voltage comparator coupled to a second reference voltage and the signal voltage, the second reference voltage different than the first reference voltage, the second voltage comparator having second negative and second positive outputs for outputting a comparison of the second reference voltage with the signal voltage; and a first arrival time comparator coupled to the first positive output and the second negative output, the first arrival time comparator having a first arrival time comparator output for outputting a comparison of the first positive output with the second negative output.