ADC Comparator Offset Calibration Using Dual-Domain Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The design of amplifiers is becoming increasingly challenging due to reduced transistor dimensions, and comparator mismatch in analog-to-digital converters (ADCs) affects the effective resolution, necessitating effective calibration techniques for comparators in ADC circuits.
Innovation Solution
A comparator offset calibration system utilizing a dual domain structure with a comparator offset evaluator and a switched-capacitor network processes digital data to generate a control signal for calibrating comparator offsets, allowing for long-term judgment and pulse width modulation-based compensation without interrupting the ADC operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If comparator offset calibration is performed using traditional methods, then offset accuracy is improved, but additional calibration cycles are required which reduce productivity
Solution Approach 1:
The calibration system performs offset evaluation and compensation in advance during idle periods or between normal conversion operations. The dual-domain structure accumulates error data over multiple conversions and applies correction before it affects subsequent measurements, thereby improving accuracy without adding calibration cycles to the critical conversion path.
Solution Approach 2:
The calibration is performed periodically rather than continuously, using accumulated error data from multiple conversion cycles. The system collects offset error information over time and applies periodic correction, maintaining high conversion speed while progressively improving accuracy through repeated measurements and corrections.
2Measurement precision
If high-precision digital processors are used for offset evaluation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs simple digital logic circuits and basic arithmetic operations instead of complex digital processors. The offset evaluation uses straightforward accumulation and comparison operations that can be implemented with minimal digital logic, dramatically reducing device complexity and cost while maintaining sufficient precision for the application.
Solution Approach 2:
The calibration system uses the ADC's own output data to evaluate and correct its own offset errors. The dual-domain structure leverages the existing digital output from normal conversions to generate calibration information, eliminating the need for external high-precision processors or separate calibration hardware.
3Measurement precision
If traditional offset calibration methods are used, then comparator mismatch is reduced, but the calibration process interrupts ADC operation reducing productivity
Solution Approach 1:
The calibration process operates continuously in the background without interrupting normal ADC conversions. The dual-domain structure allows simultaneous data acquisition for both normal conversions and calibration evaluation, ensuring uninterrupted productive operation while continuously improving offset accuracy through accumulated measurements.
Data Source
AI summary
A comparator offset calibration system having a comparator offset evaluator and a switched-capacitor network is disclosed, which is in an analog and digital dual domain structure. The comparator offset evaluator receives digital data from an analog-to-digital conversion module, evaluates an offset of a comparator of the analog-to-digital conversion module based on the received digital data, and outputs an evaluated result. The switched-capacitor network processes the evaluated result to generate a control signal. The analog-to-digital conversion module adjusts the offset of the comparator according to the control signal.