ADC Key Voltage Divider Calibration for Reliable Key Detection
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Solution Overview
Problem
Prior art analog-to-digital converter (ADC) keypads struggle to accurately distinguish between different analog input signals due to noise and power violations, leading to incorrect digital output generation and key identification.
Innovation Solution
A method involving a processor to determine and configure voltage variation ranges for each key, calculating resistive values based on a voltage dividing model, and adjusting resistor units to ensure non-overlapping voltage ranges, thereby enabling correct key identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a prior art ADC keypad is used to convert analog input signals to digital output signals, then the conversion process is simple, but noise or power violation causes each analog input signal to vary significantly, resulting in the same digital output signal being generated by converting two different analog input signals, making it impossible to correctly identify which key is pressed
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple candidate digital output signals corresponding to each analog input signal in a lookup table before actual key press detection. When an analog signal is received, the system searches the lookup table for matching digital signals and identifies the key based on pre-established correspondence, rather than attempting to directly convert the noisy analog signal. This pre-prepared reference data allows accurate key identification even when the analog signal varies due to noise or power violations.
Solution Approach 2:
The system implements feedback by using the digital output signal as a reference to search the lookup table and verify matches. The comparison process provides feedback about which pre-stored digital signals correspond to the current analog input, enabling the system to identify the pressed key through pattern matching rather than direct conversion. This feedback mechanism compensates for signal variations by finding the best match among multiple candidates.
2Manufacturing precision
If direct analog-to-digital conversion is used without calibration, then the device complexity is low, but the manufacturing precision of key identification is poor due to signal variations from noise and power violation
Solution Approach 1:
The patent applies self-service by enabling the ADC keypad system to automatically perform its own calibration and configuration. The processor executes calibration routines that automatically generate test signals, measure actual output signals, calculate correction factors, and update the lookup table without requiring external intervention or manual adjustment. This self-calibrating capability allows the system to compensate for manufacturing variations and signal noise automatically, achieving high detection precision while keeping the overall device complexity manageable through software-based solutions.
3Measurement precision
If multiple candidate digital output signals are pre-calculated and stored for each analog input signal, then accurate key identification can be achieved despite signal variations, but the quantity of data stored and processed increases
Solution Approach 1:
The patent applies segmentation by dividing the calibration and operation process into distinct phases: during calibration, multiple candidate digital signals are generated and stored in a lookup table; during normal operation, the system segments the search process by comparing the received digital signal against stored candidates and selecting the best match. This segmentation allows the system to manage large amounts of calibration data efficiently by separating data generation from data usage, and by implementing structured search algorithms that reduce processing complexity despite the increased data quantity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively differentiates between key presses by ensuring distinct digital outputs for each key, even in the presence of non-ideal factors like power noise and ADC offsets, enhancing the accuracy of key identification.
Implementation Method 1
calculating a plurality of resistive values of a voltage dividing model according to at least the divided-voltages, wherein the voltage dividing model has a plurality of voltage dividing configurations corresponding to the keys, respectively
Data Source
AI summary
A method for configuring a plurality of analog-to-digital converter (ADC) keys includes: utilizing a processor for determining a plurality of divided-voltages respectively corresponding to the Keys according to a plurality of voltage variation ranges respectively corresponding to the Keys; and calculating a plurality of resistive values of a voltage dividing model according to at least the divided-voltages, wherein the voltage dividing model has a plurality of voltage dividing configurations respectively corresponding to the keys.