SAR ADC Shared Calculator Architecture for High-Resolution Conversion
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Solution Overview
Problem
Successive approximation analog-to-digital converters are limited in precision due to imprecisions in voltage calculations, which degrade digital resolution beyond 10 bits, and existing solutions increase complexity and converter size.
Innovation Solution
A two-bit successive approximation converter design that uses a single calculator with an amplifier to calculate both intermediate voltages and residual voltages, reducing errors and complexity by mutualizing components and optimizing the comparison process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional successive approximation converters are used to achieve high digital resolution, then conversion precision is improved, but conversion time increases linearly with the number of bits
Solution Approach 1:
The converter is divided into multiple parallel conversion paths, each handling a portion of the bits. Instead of converting all n bits sequentially, the converter processes bits in parallel segments, reducing the total conversion time while maintaining high resolution precision.
Solution Approach 2:
The patent transitions from a single-dimensional sequential conversion process to a multi-dimensional parallel architecture. By introducing multiple conversion paths operating simultaneously, the system achieves high resolution without linearly increasing conversion time, effectively adding a temporal dimension to the conversion process.
2Measurement precision
If multiple calculators are used to calculate intermediate voltages for each bit conversion, then conversion precision is maintained, but device complexity and converter size increase
Solution Approach 1:
Multiple calculator functions are merged into a single shared calculator unit. This calculator is time-multiplexed to serve multiple conversion paths, calculating intermediate voltages for different bits at different time slots. This reduces the total number of calculators needed while maintaining the precision required for high-resolution conversion.
Solution Approach 2:
The single calculator is designed with universal functionality to perform multiple calculation tasks. It can calculate intermediate voltages for any bit position by being configured appropriately, making it a multi-functional component that replaces what would traditionally require multiple dedicated calculators.
3Measurement precision
If voltage calculation imprecisions are reduced to achieve higher than 10-bit resolution, then digital resolution is improved, but manufacturing precision requirements and calibration needs increase
Solution Approach 1:
The converter incorporates feedback mechanisms that monitor and correct voltage calculation imprecisions in real-time. By continuously adjusting the intermediate voltage calculations based on feedback from the conversion process, the system maintains high precision without requiring extremely tight manufacturing tolerances on the voltage reference elements.
Solution Approach 2:
The patent dynamically adjusts calculation parameters and voltage reference levels during operation to optimize precision. By changing operational parameters rather than relying solely on fixed manufacturing precision, the system achieves high digital resolution with more relaxed manufacturing requirements.
Data Source
AI summary
The analog-to-digital converter includes a first stage in which a voltage to be converted is applied to the input of a first comparator. The first comparator delivers, on a first digital output, a first digital result representative of the comparison between the voltage to be converted and the comparison voltage. The first digital output is connected to a calculator of a first intermediate voltage. A second comparator compares the first intermediate voltage with the comparison voltage and delivers a second digital result on a second digital output terminal. The second digital output terminal is connected to a second calculator of residual voltage that is a function of the voltage to be converted, of first and second voltages and of the first and second digital results. The first calculator is formed by the second calculator.