Multi-Step ADC Clocking for High-Resolution Low-Power Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analog to digital converter circuits face challenges in reducing power and area costs, particularly due to the high number of comparators required, which limits operating frequency and increases power consumption, especially in high-resolution conversions.
Innovation Solution
The implementation of partially clocked, multi-step analog to digital converters with a clocked fine conversion stage, a clocked coarse conversion stage, and a clock circuit, where only a subset of comparators are actively clocked based on the output of the coarse conversion stage, reducing power consumption and area requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the number of comparators is reduced to lower power consumption and area costs, then power and area efficiency is improved, but the resolution and accuracy of analog to digital conversion deteriorates
Solution Approach 1:
The comparator bank is divided into multiple groups, each group responsible for a specific voltage range. The coarse conversion stage identifies the appropriate voltage range, and only the corresponding comparator group is activated for fine conversion. This segmentation allows the system to maintain high resolution within the active range while keeping the number of simultaneously active comparators low, thus reducing power consumption.
Solution Approach 2:
The system dynamically activates only the necessary subset of comparators based on the coarse conversion result. The clock signal is selectively applied to enable only the relevant comparator group for each conversion cycle, making the comparator activation dynamic rather than static. This dynamic approach ensures that only the minimum required number of comparators consume power at any given time.
2Area of stationary object
If the number of comparators is reduced to decrease area costs, then area efficiency is improved, but the operating frequency and speed of conversion deteriorates
Solution Approach 1:
The two-stage architecture segments the conversion process into coarse and fine stages. The coarse stage quickly identifies the voltage range using fewer comparators, and the fine stage then performs high-speed conversion within that range. This segmentation allows the circuit to maintain high operating frequency by limiting the number of comparators that need to be simultaneously evaluated.
Solution Approach 2:
The coarse conversion stage performs preliminary action by pre-identifying the voltage range before the fine conversion stage operates. This preliminary classification allows the fine conversion stage to focus on a narrower voltage range, reducing the number of comparators needed and enabling faster operation since fewer comparisons are required to achieve the final high-resolution result.
3Measurement precision
If a full comparator bank is used to achieve high-resolution conversion, then conversion accuracy is improved, but power consumption and area costs increase
Solution Approach 1:
The comparator bank is segmented into multiple groups corresponding to different voltage ranges. Only the group relevant to the current input voltage is activated, while other groups remain inactive. This segmentation maintains the ability to achieve high-resolution conversion accuracy within the active range while significantly reducing the number of comparators consuming power at any given time.
Solution Approach 2:
Instead of activating the full comparator bank, the system uses partial action by activating only the necessary subset of comparators required for the current conversion. The coarse conversion result determines which subset is needed, and only that subset is activated. This partial activation achieves the required conversion accuracy with minimal power consumption.
4Speed
If a full comparator bank is used to ensure high-speed operation, then operating frequency is improved, but the number of comparators and area requirements increase
Solution Approach 1:
The conversion process is segmented into two stages: coarse conversion that quickly identifies the voltage range, and fine conversion that achieves high-speed operation within that range. This segmentation allows the circuit to maintain high operating frequency by limiting the number of comparators active at any time, thus reducing the area required while preserving speed performance.
Solution Approach 2:
The coarse conversion stage performs preliminary classification of the input voltage into a specific range before the fine conversion stage processes it. This preliminary action reduces the search space for the fine conversion stage, allowing it to operate at high speed with fewer comparators, thereby reducing the overall circuit area while maintaining high operating frequency.
Data Source
AI summary
Various different approaches are provided for conversion of analog signals to digital signals. For example, various partially clocked, multi-step analog to digital converters are discussed. Such analog to digital converters include a clocked fine conversion stage, a clocked coarse conversion stage, and a clock circuit. The fine conversion stage includes a first group of comparators clocked by a first clock and a second group of comparators clocked by a second clock. The first group of comparators is operable to compare an input voltage with a first fine reference voltage range, and the second group of comparators is operable to compare the input voltage with a second fine reference voltage range. The coarse conversion stage includes a group of clocked comparators that are operable to compare the input voltage with a coarse reference voltage range. The clock circuit selectably asserts one of the first clock and the second clock based at least in part on an output of the second conversion stage.