Dual Oscillator ADC Architecture for Fast, Linear Conversion
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Solution Overview
Problem
Conventional analog-to-digital converters face challenges in achieving high resolution and fast conversion times simultaneously, with high sampling frequencies leading to noise and bandwidth issues, and are prone to linearity and sampling frequency errors due to PVT variations.
Innovation Solution
A device comprising two oscillator-based analog-to-digital converters and output logic that generates a digital output signal by combining the outputs of both converters, with one converter receiving an analog input signal and the other a reference signal, allowing for compensation of PVT variations without a clock signal, thereby improving accuracy and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resolution of the analog-to-digital converter is increased, then measurement precision is improved, but conversion time increases
Solution Approach 1:
The patent divides the conversion process into two independent parallel paths: one path processes the analog input signal through a first oscillator-based ADC, while the other path processes an analog reference signal through a second oscillator-based ADC. This segmentation allows both high-resolution measurement and fast conversion to occur simultaneously in different channels, resolving the contradiction between resolution and conversion time.
2Productivity
If sampling frequency is increased to improve conversion speed, then conversion time is reduced, but noise and bandwidth requirements increase
Solution Approach 1:
The patent introduces an intermediary differential measurement approach where the reference signal path acts as a mediator to compensate for common-mode disturbances. By comparing the input signal path with the reference signal path, the system can achieve fast conversion without excessively high sampling frequencies, as the differential structure rejects noise and reduces bandwidth requirements compared to single-ended high-speed conversion.
3Loss of time
If conventional oscillator-based converters are used for fast conversion, then conversion time is reduced, but linearity and sampling frequency error increase due to PVT variations
Solution Approach 1:
The patent applies the counterweight principle by using the second oscillator-based ADC processing the reference signal to compensate for PVT variations affecting the first ADC. The reference path acts as a counterbalancing mechanism that measures and compensates for frequency errors and linearity deviations caused by process, voltage, and temperature variations, enabling fast conversion while maintaining high linearity and accuracy.
Data Source
AI summary
A device is provided comprising a first oscillator based analog-to-digital converter configured to receive an analog input signal and output a first digital signal and a second oscillator based analog-to-digital converter configured to receive an analog reference signal and output a second digital signal. The device further comprises output logic configured to generate a digital output signal based on the first digital signal and the second digital signal.