A/D Converter Limit Value Calibration for Abnormality Detection
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Solution Overview
Problem
Variations in A/D converter characteristics lead to differing A/D converted values for the same power-supply voltage across electronic devices, necessitating a method to maintain a stable voltage range without narrowing the estimated width.
Innovation Solution
A method involving the fabrication of electronic devices with a port, A/D converter, memory, and determination circuit, where a predetermined voltage is inputted during fabrication to record the corresponding A/D converted value as a limit value in memory, ensuring a unified criterion for abnormality determination across devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed voltage range is used for abnormality determination across all electronic devices, then the determination criterion is simple and unified, but the variation in A/D converter characteristics causes inaccurate abnormality detection in individual devices
Solution Approach 1:
The patent applies preliminary action by recording the A/D converted value corresponding to a predetermined voltage (e.g., 5V) during the fabrication process into the memory of each electronic device. This pre-recorded value serves as the limit value for subsequent abnormality determinations. By performing this calibration action during fabrication rather than requiring complex real-time adjustments, the system achieves device-specific accuracy without adding operational complexity.
Solution Approach 2:
The patent changes the parameter of the limit value from a fixed universal value to a device-specific value recorded in memory. Each electronic device has its own limit value stored in its memory, which corresponds to the A/D converted value of a predetermined voltage for that specific device. This parameter change allows each device to account for its individual A/D converter characteristics while maintaining a simple determination process.
2Measurement precision
If the voltage range is narrowed to account for A/D converter variations, then abnormality detection accuracy improves, but the estimated width of the power-supply voltage increases
Solution Approach 1:
The patent changes the limit value parameter to be device-specific by recording the actual A/D converted value of a predetermined voltage during fabrication. This allows each device to have an accurate reference point that accounts for its individual characteristics, thereby improving voltage measurement accuracy without requiring an overly wide safety margin.
Solution Approach 2:
By performing the voltage calibration and recording the A/D converted value during fabrication, the system establishes an accurate baseline for each device before it enters service. This preliminary characterization eliminates the need to use a wide voltage range to accommodate all possible variations, as each device is individually calibrated.
3Reliability
If individual calibration is performed for each electronic device, then A/D converter variation is compensated, but the fabrication process becomes more complex
Solution Approach 1:
The patent performs the calibration action during the fabrication process by inputting a predetermined voltage and recording the A/D converted value into the device's memory. This preliminary calibration is integrated into the manufacturing flow, allowing each device to be individually characterized for reliable abnormality determination without requiring complex post-fabrication adjustment mechanisms.
Solution Approach 2:
The system uses the device's own A/D converter to measure the predetermined voltage and store the resulting converted value in its own memory. Each electronic device calibrates itself during fabrication without requiring external calibration equipment or complex adjustment procedures, thereby improving reliability while maintaining fabrication simplicity.
Data Source
AI summary
A method of fabricating an electronic device is provided, where the electronic device includes a port, an A/D converter, a memory, and a determination circuit. The determination circuit is configured to determine whether or not there is an abnormality by comparing an A/D converted value as a result of the A/D converter converting a voltage based on a power-supply voltage inputted to the port with a limit value stored in the memory. The method includes a step of inputting a predetermined voltage to the port of the electronic device to be fabricated, and a step of recording an A/D converted value as a result of the A/D converter converting a voltage based on the predetermined voltage inputted to the port as the limit value in the memory.