Flash ADC Comparator Interpolation for Faster High-Resolution Conversion
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Solution Overview
Problem
Existing high-speed analog-to-digital converters (ADCs) in multi-gigabit serial data links face challenges with resolution, conversion time, power consumption, and input load, particularly as the number of bits increases.
Innovation Solution
The implementation of a reduced number of comparators combined with interpolation circuits, utilizing adjustable delay circuits and SR latches to determine comparator output timing, reduces conversion time, load, and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional flash ADC uses a large number of comparators to achieve high resolution, then the resolution is improved, but the conversion time increases and power consumption increases
Solution Approach 1:
The patent divides the comparator array into multiple groups, where each group handles a specific range of input values. By segmenting the comparison task across multiple groups that can operate in parallel, the system achieves high resolution without requiring all comparators to operate simultaneously, thereby reducing conversion time while maintaining measurement precision.
Solution Approach 2:
The patent implements preliminary comparison stages that quickly eliminate large portions of the input range before final precision comparison. By performing coarse comparison first and then refining the result with fewer comparators, the system achieves high resolution with reduced conversion time, as the preliminary action narrows down the search space before detailed measurement.
2Measurement precision
If a conventional flash ADC uses a large number of comparators to achieve high resolution, then the resolution is improved, but the power consumption increases
Solution Approach 1:
The patent segments the comparator functionality across multiple groups that operate in a time-multiplexed or parallel fashion. This segmentation allows the system to achieve high resolution through coordinated operation of fewer active comparators at any given moment, reducing overall power consumption while maintaining measurement precision through the collective capability of the segmented groups.
Solution Approach 2:
The patent employs partial action by activating only the necessary subset of comparators for each conversion cycle based on the input signal characteristics. Rather than all comparators operating continuously, the system dynamically engages only those needed to achieve the required resolution, thereby reducing power consumption while maintaining measurement precision when needed.
3Measurement precision
If a conventional flash ADC uses a large number of comparators, then the resolution is improved, but the input load increases
Solution Approach 1:
The patent segments the input signal processing across multiple comparator groups, where each group receives and processes a portion of the input range. This segmentation distributes the input load across multiple stages rather than concentrating it on a single large comparator array, thereby reducing the instantaneous input load while maintaining the ability to achieve high resolution through coordinated group operation.
4Use of energy by stationary object
If the number of comparators is reduced to decrease power consumption and circuit area, then power and area are improved, but the resolution may deteriorate
Solution Approach 1:
The patent merges the functionality of multiple comparator groups to achieve the resolution equivalent of a full comparator array. By combining the output signals and decision logic from several groups that each use fewer comparators, the system achieves the same measurement precision as a conventional design would provide, while using fewer total comparators to reduce power consumption and circuit area.
Solution Approach 2:
The patent transitions from a single-dimension comparator array to a multi-dimensional architecture involving multiple groups with inter-group signaling and coordination. This dimensional change allows the system to achieve high resolution through the collective operation of distributed groups rather than a dense single array, reducing the number of comparators needed while maintaining measurement precision through the added organizational dimension.
Data Source
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AI summary
An analog-to-digital converter (ADC) circuit includes a first comparator circuit, a second comparator circuit, and an interpolation circuit. The first comparator circuit includes a first input terminal to receive a first reference voltage signal and a second input terminal to receive an input voltage signal. The second comparator circuit includes a first input terminal to receive a second reference voltage signal and a second input terminal to receive the input voltage signal. The interpolation circuit includes a first input terminal coupled to a first output terminal of the first comparator and a second input terminal coupled to a first output terminal of the second comparator.