I2C Input Threshold Switching for 1.2 V and 1.8 V Signal Detection
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Solution Overview
Problem
Existing I2C interface devices struggle to support both 1.8 V and 1.2 V standards due to insufficient input hysteresis margin, making it difficult to accurately detect signal levels across different voltage specifications.
Innovation Solution
The apparatus includes a communication interface with adjustable judgement thresholds, utilizing multiple input detectors and a reference voltage generation circuit to dynamically switch between 1.8 V and 1.2 V standards by selecting appropriate input detectors based on comparison results, ensuring accurate signal detection across both voltage specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed judgement threshold is used in the input circuit, then the circuit structure remains simple, but the apparatus cannot accurately detect signal levels across both 1.8 V and 1.2 V I2C standards
Solution Approach 1:
The patent implements dynamic adjustment of the judgement threshold in the input circuit based on the detected voltage level. The threshold is switched between a first threshold (for 1.8 V standard) and a second threshold (for 1.2 V standard) depending on the operating voltage, enabling the circuit to adapt to different voltage standards while maintaining accurate signal detection
Solution Approach 2:
The patent changes the judgement threshold parameter according to the operating voltage condition. When the voltage level exceeds the first reference voltage (indicating 1.8 V standard), the first threshold is used; when it does not exceed (indicating 1.2 V standard), the second threshold is used. This parameter adaptation resolves the contradiction between fixed simple structure and multi-standard compatibility
2Adaptability or versatility
If the judgement threshold is adjusted to support both voltage standards, then multi-standard compatibility is achieved, but the input circuit structure becomes more complex
Solution Approach 1:
The patent segments the input circuit into multiple functional blocks: a voltage level detection unit, a threshold selection unit, and an input detection unit. This segmentation allows each component to perform a specific function, making the overall complex structure manageable and modular while achieving multi-standard support
Solution Approach 2:
The patent performs preliminary detection of the voltage level before signal detection. The voltage level detection unit determines whether the operating voltage corresponds to the 1.8 V or 1.2 V standard in advance, and pre-selects the appropriate judgement threshold before the actual signal detection occurs, ensuring correct operation without requiring complex real-time adjustment mechanisms
Data Source
AI summary
Provided is an apparatus including: a first input circuit which inputs signal from a first communication line; a second input circuit which inputs a signal from a second communication line; a reference voltage generation circuit which generates a reference voltage; and a comparison circuit which compares the reference voltage with a voltage of the first communication line. The first input circuit and the second input circuit adjust judgement thresholds to be used for judging a signal value according to the comparison result obtained by the comparison circuit.