Asynchronous SAR ADC PVT Timing Control for Accurate Fast Conversion
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Solution Overview
Problem
Conventional Successive Approximation Register (SAR) Analog-to-Digital Converters (ADCs) face inefficiencies due to variations in process, voltage, and temperature (PVT) conditions, leading to compromised performance and increased power consumption, as they are optimized for specific corners rather than overall conditions.
Innovation Solution
A PVT processor is integrated into the SAR ADC to optimize performance across different PVT corners by using sensors and an optimization algorithm that adjusts the internal self-time clock delay and supply voltage, ensuring maximum binary search time and improved DAC and Reference settling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ADC is optimized for fast process corner with shorter pulse spacing, then the conversion rate is improved, but the DAC and Reference settling time is reduced leading to erroneous comparator results and degraded SNR
Solution Approach 1:
The patent implements dynamic adjustment of the delay element based on process corner detection. The system transitions from a static delay configuration to a dynamic one where the delay value is automatically adjusted according to the detected process corner (slow, typical, or fast), allowing the ADC to maintain optimal performance across varying process conditions without sacrificing reliability.
Solution Approach 2:
The patent changes the delay parameter of the delay element based on detected process corners. By detecting which process corner the ADC is operating at and adjusting the delay element's delay value accordingly, the system optimizes the pulse spacing to ensure adequate DAC and Reference settling time while maintaining high conversion rates.
2Loss of time
If the delay element time delay is reduced for fast corner optimization, then the binary search completes faster, but the DAC and Reference cannot settle before the next bit-test clock arrives causing errors
Solution Approach 1:
The system dynamically adjusts the delay element's time delay based on the detected process corner. For fast process corners, the delay is reduced to complete binary search faster, while for slow corners, the delay is increased to ensure proper settling. This dynamic adaptation resolves the contradiction between speed and precision.
Solution Approach 2:
The patent changes the delay parameter of the delay element according to process corner detection. By adjusting this critical timing parameter, the system ensures that the binary search completes in time while leaving sufficient settling time for DAC and Reference, thereby maintaining manufacturing precision.
3Productivity
If the ADC timing is compromised to one specific corner condition, then the performance is optimized for that corner, but the performance degrades under other PVT conditions
Solution Approach 1:
The patent implements a universal solution that handles multiple process corners (slow, typical, fast) within a single ADC design. The process corner detection mechanism identifies the current operating corner and adjusts the delay element accordingly, allowing the ADC to maintain optimal performance across all PVT conditions rather than being optimized for just one corner.
Solution Approach 2:
The system employs feedback through process corner detection to automatically adjust the delay element. The detection mechanism provides feedback about the current process corner, which triggers appropriate adjustments to the delay element, enabling the ADC to adapt and maintain high performance across varying PVT conditions.
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.