Nested Lookup Table ADC Circuit for Low-Latency Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analog-to-digital converters (ADCs) face challenges in reducing latency and often require digital signal processors (DSPs) to determine output vectors, which can increase complexity and processing time.
Innovation Solution
The proposed solution involves an analog-to-digital converter circuit with sub-ADCs and a nested lookup table subtractor circuit, which generates encoded output vectors and selects output values from a nested lookup table, reducing the need for DSPs and minimizing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a digital signal processor (DSP) is used to determine the output vector, then the conversion accuracy can be improved, but the latency and processing time increase
Solution Approach 1:
The patent pre-calculates and stores all possible subtraction results in a lookup table before the ADC conversion process. During operation, the system simply retrieves pre-computed values based on the thermometer codes from sub-ADCs, eliminating the need for real-time DSP calculations and reducing latency while maintaining accuracy
Solution Approach 2:
The patent replaces the mechanical/DSP-based subtraction and processing system with a lookup table-based retrieval system. Instead of performing complex digital signal processing operations, the system uses simple table lookups to determine the output vector, significantly reducing processing time
2Measurement precision
If a digital signal processor (DSP) is used to determine the output vector, then the conversion accuracy can be improved, but the device complexity increases
Solution Approach 1:
The patent extracts the complex DSP processing function and replaces it with a lookup table that stores pre-computed results. The complex subtraction and processing logic is removed from the active processing path, leaving only simple retrieval operations that significantly reduce device complexity
Solution Approach 2:
The patent substitutes the DSP-based processing mechanism with a lookup table retrieval mechanism. This replacement eliminates the need for complex digital signal processing hardware while maintaining the ability to accurately determine output vectors
3Speed
If a traditional lookup table is used, then the processing speed can be improved, but the memory requirements and table size become excessively large
Solution Approach 1:
The patent segments the single large lookup table into multiple smaller nested lookup tables organized in a hierarchical structure. The first lookup table stores coarse-resolution results, and subsequent lookup tables store fine-resolution corrections, allowing the system to achieve high precision without requiring a single large memory structure
Solution Approach 2:
The patent implements a nested lookup table structure where smaller lookup tables are effectively contained within the hierarchical framework of larger tables. The first lookup table provides base values, and nested subsequent tables provide incremental corrections, creating a compact multi-level storage system that reduces overall memory requirements while maintaining processing speed
Data Source
AI summary
Disclosed herein is an analog-to-digital converter circuit configured for digitizing an analog input signal. The analog-to-digital converter comprises an analog input configured for receiving the analog input signal. The analog-to-digital converter circuit further comprises at least one sub-ADC connected to the analog input signal, wherein the at least one sub-ADC is configured to output at least one encoded output vector in response to receiving the analog input signal. The analog-to-digital converter circuit further comprises a lookup circuit comprising a nested lookup table. The lookup circuit is configured to select an output value from the nested lookup table using the at least one encoded output vector, wherein the lookup circuit is configured to provide the output value as the digitization of the analog input signal.