Keyboard Scanning Circuit Wire Aging Adaptation
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Solution Overview
Problem
Keyboard matrix type button switch circuits experience accuracy issues in pressing detection due to wire aging, which increases impedance and capacitance, leading to errors in voltage detection.
Innovation Solution
A keyboard with wire aging self-adaptation, featuring a scanning circuit with a processor and memory that updates response time parameters based on time differences between scanning and return signal durations, ensuring accurate pressing detection by adjusting scanning signal timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the keyboard uses fixed scanning duration for voltage detection, then the circuit operation is simple, but wire aging causes detection accuracy to deteriorate
Solution Approach 1:
The patent implements dynamic scanning duration adjustment based on detected wire aging characteristics. The controller adapts the scanning time for each scanning line individually, changing from fixed to variable durations to compensate for impedance and capacitance changes caused by wire aging, thereby maintaining detection accuracy without requiring complex hardware modifications
Solution Approach 2:
The system employs feedback mechanisms where the controller continuously monitors the voltage detection results and adjusts the scanning duration accordingly. By detecting the actual electrical characteristics of each scanning line and returning this information to the controller, the system self-corrects for wire aging effects, improving measurement precision while keeping the overall system architecture relatively simple
2Measurement precision
If the scanning duration is extended to account for wire aging, then detection accuracy is improved, but the scanning time increases
Solution Approach 1:
The patent applies different scanning durations to different scanning lines based on their individual wire aging characteristics. Instead of uniformly extending the scanning duration for all lines, the system identifies which specific lines require longer scanning times and adjusts only those, thereby maintaining detection accuracy while minimizing the overall scanning time penalty
Solution Approach 2:
The system dynamically changes the scanning duration parameter for each scanning line based on detected electrical characteristics. By adjusting this temporal parameter adaptively rather than using a fixed value, the system achieves accurate detection of aged wires without unnecessarily extending the total scanning cycle time for all lines
Data Source
AI summary
A keyboard with wire aging self-adaption, a self-adaption method for keyboard, an electronic computing device readable medium with a stored program, and an electronic computing device program product are provided. In the keyboard, a processor feeds a scanning signal to each scanning line in turn during a scanning round. In response to the conduction state of one of switching elements, the processor detects a return signal on the corresponding return line and selects one or more scanning lines as a testing line. During a first duration in which the testing line maintains the scanning signal, according to the time difference between the starting points of the first duration and the return signal and the response time parameter corresponding to the testing line that is stored in the memory, the processor determines whether to update the response time parameter corresponding to the testing line that is stored in the memory.