Voltage-to-Delay Preamplifier Calibration for ADC Gain Mismatch
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Solution Overview
Problem
Conventional analog-to-digital converters face challenges in achieving high-speed operation with reduced area and power requirements, and they often suffer from gain mismatch and saturation issues that affect their performance.
Innovation Solution
The proposed analog-to-digital converter system employs a voltage-to-delay frontend with preamplifiers and a delay-resolving backend, utilizing a calibration engine to adjust preamplifiers based on single-bit digital signals, ensuring optimal gain matching and avoiding saturation through processes like common-current and capacitance adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional analog-to-digital converters are used to achieve high-speed operation, then the conversion speed can be increased, but the area and power requirements increase
Solution Approach 1:
The converter is divided into multiple sub-ranges, with each preamplifier handling a specific sub-range. This segmentation allows the use of simpler, smaller preamplifiers for each segment rather than one large high-speed converter, reducing overall area while maintaining high conversion speed through parallel operation of multiple preamplifiers
Solution Approach 2:
The patent transitions from traditional voltage-domain conversion to delay-domain conversion by converting voltage differences into time delays. This dimensional change from voltage to time allows for more efficient resource utilization and reduced hardware complexity, achieving high speed with smaller area
2Speed
If conventional analog-to-digital converters are used to achieve high-speed operation, then the conversion speed can be increased, but the power consumption increases
Solution Approach 1:
By segmenting the conversion task across multiple preamplifiers, each operating at lower power individually, the total power consumption is reduced compared to a single high-speed converter. The segmented architecture allows energy-efficient operation in each sub-range while achieving overall high conversion speed
Solution Approach 2:
The patent replaces traditional high-power voltage comparison mechanisms with delay-based comparison mechanisms. The voltage-to-delay conversion process uses less energy-intensive operations, substituting mechanical/electrical power-heavy operations with time-domain processing that consumes less power
3Adaptability or versatility
If preamplifiers with different threshold voltages are used to expand the input range, then the adaptability is improved, but gain mismatch occurs affecting measurement precision
Solution Approach 1:
A calibration process is performed before normal operation to measure and compensate for gain mismatches among preamplifiers. This preliminary calibration action stores correction data that is applied during conversion, allowing the system to maintain high measurement precision across the expanded input voltage range despite inherent gain variations
Solution Approach 2:
The system implements feedback through the calibration process, where gain mismatch information is measured and used to adjust subsequent conversions. This feedback mechanism compensates for gain variations, maintaining measurement precision while preserving the expanded adaptability benefits
4Measurement precision
If the preamplifier gain is increased to improve sensitivity, then the measurement precision is improved, but saturation issues occur
Solution Approach 1:
The input voltage range is divided into multiple sub-ranges, with each preamplifier optimized for a specific sub-range. This segmentation allows each preamplifier to operate at optimal gain settings for its designated range, improving sensitivity within that range while preventing saturation by directing appropriately scaled inputs to the correct preamplifier
Solution Approach 2:
Each preamplifier is designed with specific local characteristics optimized for its designated sub-range. This local optimization allows each preamplifier to have high gain and sensitivity for its specific range while the overall system maintains reliability through proper input distribution, preventing any single preamplifier from saturating
Data Source
AI summary
A method of using an analog-to-digital converter system includes receiving a sampled voltage corresponding to one of an input voltage and a known voltage, causing preamplifiers to generate output signals based on the sampled voltage, generating first and second signals based on the output signals, causing a delay-resolving delay-to-digital backend to generate a single-bit digital signal representing an order of receipt of the first and second signals, and adjusting one or more of the preamplifiers based on the digital signal. The disclosure also relates to a system which includes a voltage-to-delay frontend and a delay-resolving backend, and to a method which includes causing a delay comparator to generate a single-bit digital signal representing an order of receipt of input signals, causing the comparator to transmit a residue delay signal to a succeeding comparator, and transmitting a signal to adjust one or more of the preamplifiers based on the digital signal.