Capacitive Sensor Electrode Evaluation with Multi-Cycle Charge Exchange
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for evaluating capacitance values of capacitive sensor electrodes are costly due to the need for high-bit resolution analog-digital converters, which increases costs without significantly improving accuracy.
Innovation Solution
A method involving multiple recharging cycles with varying numbers of processes, where the sensor electrode is charged and then coupled with a storage capacitor, allowing charge exchange, and recording parameters to form a total value that can be accurately represented with fewer bits, thereby improving resolution without increasing hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-bit resolution analog-digital converters are used to evaluate capacitance values, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The evaluation process is divided into multiple recharging cycles, each contributing to the final capacitance value. Instead of requiring a single high-resolution measurement, the total capacitance is segmented into multiple lower-resolution measurements that are summed together, achieving high precision through accumulation of multiple 8-bit values rather than requiring a single high-bit converter
Solution Approach 2:
The sensor electrode undergoes periodic recharging cycles with a storage capacitor, where each cycle transfers charge and generates a measurable parameter. This periodic action allows the system to accumulate measurement data over multiple cycles, improving effective resolution through temporal averaging and summation without requiring higher-bit hardware
2Measurement precision
If multiple recharging cycles with varying processes are implemented, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The number of recharging processes varies dynamically between cycles based on the detected parameter values. When the accumulated sum approaches the maximum representable value, subsequent cycles use fewer recharging processes, optimizing the balance between precision and speed adaptively rather than using a fixed number of cycles
Solution Approach 2:
The system uses feedback from previously detected parameter values to adjust the number of recharging processes in subsequent cycles. This feedback mechanism allows the system to learn from past measurements and optimize future evaluation cycles, maintaining high precision while minimizing unnecessary measurement cycles
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
This method achieves improved resolution in evaluating capacitance values with existing hardware, reducing costs while maintaining accuracy by ensuring the sum or difference of recorded parameters falls between two bits or is minimally deviated from the center, effectively doubling the sensor sensitivity's resolution.
Implementation Method 1
The sensor electrode then forms a capacitance with a reference electrode
Implementation Method 2
the electrostatic properties of the entire sensor electrode-vehicle-vehicle electronics system change
Implementation Method 3
charge carriers stored in the sensor electrode are transferred to the storage capacity
Implementation Method 4
Methods known from practice for determining capacity values of sensor electrodes use the principle of periodically charging and/or discharging the sensor electrode
Data Source
Figure 1a~1b
Figure 2a~2b
AI summary
The invention relates to a method for evaluating capacitance values of a capacitive sensor electrode, comprising the following steps: a) coupling the sensor electrode to a charging circuit, b) uncoupling the sensor electrode from the charging circuit and coupling the sensor electrode to a storage circuit, c) capturing a parameter dependent on the capacitance of the sensor electrode as an ADC value after the change exchange cycle has ended. At least two charge exchange cycles are performed and respective associated parameters Ai are captured and used to evaluate the capacitance value. The invention also relates to a modified method and to a proximity sensor assembly.