Automatic Clamping ADC Feedback for Offset Drift Correction
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Solution Overview
Problem
Conventional analog-to-digital converters in video signal processing devices face inaccuracies due to misjudgment of the clamping interval by microcontrollers and temperature drift, leading to inaccurate digital signal outputs, and the addition of microcontrollers increases manufacturing costs.
Innovation Solution
An automatic clamping A/D converter is developed, incorporating a comparator and bidirectional counter to compare the digital signal with an offset value during the clamping interval, adjusting the signal to match the offset value, thereby eliminating the need for a microcontroller and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microcontroller is used to adjust the offset value to improve digital signal accuracy, then the digital signal accuracy is improved, but the manufacturing cost increases and the system becomes more complex
Solution Approach 1:
The patent implements self-service by enabling the A/D converter to automatically adjust its own offset value using an internal bidirectional counter and D/A converter. The system monitors its own output digital signal and performs automatic calibration without external microcontroller intervention, thereby eliminating the need for additional control components while maintaining high accuracy.
Solution Approach 2:
The patent employs feedback mechanisms where the output digital signal is fed back to the bidirectional counter, which compares the signal against reference levels and automatically adjusts the offset value through the D/A converter. This closed-loop feedback system ensures continuous accuracy maintenance without requiring complex external control logic.
2Measurement precision
If a microcontroller is used to analyze and adjust the offset value, then the digital signal accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive microcontroller components with simpler, more cost-effective integrated circuit elements such as bidirectional counters and D/A converters that can be directly integrated into the A/D converter architecture. This substitution significantly reduces manufacturing costs while achieving the same functional outcome of automatic offset calibration.
Solution Approach 2:
The patent extracts the microcontroller function from the system by implementing the offset adjustment capability directly within the A/D converter using dedicated hardware components. This extraction eliminates the need for separate control units and reduces overall system complexity and manufacturing cost.
3Ease of manufacture
If the A/D converter operates without microcontroller control, then the manufacturing cost is reduced, but the digital signal accuracy may deteriorate due to temperature drift and other factors
Solution Approach 1:
The patent implements dynamic adaptation by enabling the bidirectional counter and D/A converter to continuously monitor and adjust the offset value in real-time based on temperature drift and other environmental factors. This dynamic adjustment mechanism ensures that the system maintains high signal accuracy under varying operating conditions without requiring microcontroller control.
Solution Approach 2:
The patent performs preliminary calibration actions through the bidirectional counter and D/A converter to pre-compensate for expected temperature drift and environmental variations. By proactively adjusting the offset value before accuracy degradation occurs, the system maintains reliable performance without needing continuous microcontroller intervention.
Data Source
AI summary
An automatic clamping analog-to-digital converter (A/D converter) is provided, which includes an A/D converter, a switch, a comparator, a bidirectional counter, and a digital-to-analog converter (D/A converter). Wherein, the A/D converter receives an analog signal from a node, and then converts the analog signal into a digital signal according to a DC offset level. The switch is coupled between the node and a fixed voltage level, and is turned on or off according to a clamping signal. The comparator outputs a compare signal according to a comparison result between the digital signal and an offset value. The bidirectional counter outputs a count, and increases or decreases the count according to the compare signal. The D/A converter converts the count into the DC offset level and provides the DC offset level to the A/D converter.