Asynchronous SAR ADC PVT Optimization for Clock Delay Tuning
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Solution Overview
Problem
Conventional Successive Approximation Register (SAR) Analog-to-Digital Converters (ADCs) face inefficiencies due to varying process, voltage, and temperature (PVT) conditions, leading to suboptimal performance and increased power consumption, as they are often optimized for a specific corner condition, resulting in compromised conversion rates and Signal-to-Noise ratio (SNR).
Innovation Solution
A PVT processor is integrated into the SAR ADC to optimize performance across different PVT corners by using a process sensor, temperature sensor, voltage regulator, and optimization algorithm, which performs coarse and fine optimizations to adjust the bit-test clock delay and supply voltage, ensuring maximum binary search time and improved DAC and Reference settling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ADC is optimized for fast process corner with shorter bit-test clock delay, then conversion rate is improved, but DAC and Reference settling time is reduced leading to degraded SNR
Solution Approach 1:
The patent implements dynamic adjustment of bit-test clock delay based on detected process corner characteristics. The system transitions from a static, fixed delay approach to a dynamic one where the delay is adapted in real-time according to the detected process corner (slow, typical, or fast), allowing optimal balance between conversion rate and settling time for each specific process condition.
Solution Approach 2:
The patent changes the bit-test clock delay parameter according to the detected process corner. By detecting which process corner the ADC is operating at and adjusting the corresponding delay parameter, the system optimizes both conversion rate and SNR for each specific process condition rather than compromising for a single corner.
2Reliability
If the bit-test clock delay is fixed for slow process corner, then DAC settling time is sufficient for slow corner, but conversion rate is limited and fast corner cannot achieve optimal performance
Solution Approach 1:
The system dynamically selects bit-test clock delay values based on detected process corner characteristics. Instead of using a fixed delay that compromises fast corner performance, the system adapts the delay parameter in real-time, switching between different delay values optimized for slow, typical, or fast process corners respectively.
Solution Approach 2:
The patent implements parameter changes by adjusting the bit-test clock delay according to the detected process corner. The system maintains reliability for slow corner by using appropriate delay values while simultaneously enabling high conversion rates for fast corner through parameter adaptation.
3Measurement precision
If higher current is consumed to ensure DAC settles within stringent fast corner timing, then settling accuracy is improved, but power consumption increases
Solution Approach 1:
The patent changes the timing parameter (bit-test clock delay) to match process corner characteristics rather than increasing power consumption. By detecting the process corner and adjusting the delay parameter accordingly, the system achieves accurate settling without unnecessarily consuming higher power in all operating conditions.
Solution Approach 2:
The system uses process corner detection to automatically adjust its own timing parameters without external intervention. The ADC self-adapts its bit-test clock delay based on the detected process corner, eliminating the need for manual optimization or excessive power consumption to handle process variations.
Data Source
AI summary
A method of enhancing SAR ADC performance includes employing PVT processor to correct process, voltage and temperature (PVT) variation. The PVT processor senses process, supply voltage and temperature information then maximize the time for SAR binary search process. The PVT processor first applies coarse optimization to correct process and voltage variation then applies fine optimization to correct the temperature variation. The SAR ADC is operated at its optimized PVT condition and its performance is enhanced after PVT optimization.