Vehicle Door Handle Capacitance Detection Using Threshold Timing
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Solution Overview
Problem
Existing systems for detecting changes in a vehicle's environment using sensor elements, such as door handles, require high-resolution analog-digital converters for precise charge state determination, which increases technical effort and impairs sensitivity and speed, especially for minor changes.
Innovation Solution
An electronic circuit arrangement with a control device and a time recording arrangement that evaluates the state of charge over time, allowing for improved sensitivity and speed by measuring the temporal changes in capacitance without the need for high-resolution analog-digital converters, using a comparator and timer to determine the state of charge based on the time it takes for the voltage to reach a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution analog-to-digital converter is used to determine the charge state of the holding capacitor, then the measurement precision of the charge level is improved, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the analog-to-digital converter (electronic measurement system) with a timer-based temporal evaluation system. Instead of measuring voltage directly with high-resolution ADC, the system converts the charge state measurement into a time measurement problem, using a timer to record the time required for the holding capacitor to reach a threshold voltage level. This substitution of measurement methodology reduces device complexity while maintaining measurement capability.
Solution Approach 2:
The patent introduces a threshold voltage level as an intermediary reference point. The timer measures the time required for the holding capacitor voltage to reach this intermediate threshold, rather than directly measuring the full voltage range. This intermediary approach simplifies the measurement system by converting a precision voltage measurement problem into a time measurement problem, which can be solved with lower-cost components.
2Measurement precision
If a high-resolution analog-to-digital converter is used to detect minor changes in charge level, then the sensitivity of detection is improved, but the device complexity increases
Solution Approach 1:
The patent transforms the measurement from a voltage dimension to a time dimension. Instead of measuring small voltage changes directly (which requires high-resolution ADC), the system measures the time required for the voltage to evolve to a threshold level. This dimensional transformation allows minor charge level changes to be detected through temporal differences rather than voltage resolution, reducing the complexity requirements.
Solution Approach 2:
The system performs preliminary charging of the holding capacitor through repeated charge transfers from the sensor element before the actual measurement. This preliminary action accumulates the charge state changes, making minor changes more detectable through the subsequent temporal measurement, thereby improving sensitivity without requiring high-resolution conversion during the critical measurement phase.
3Measurement precision
If repeated charge transfers are performed to determine the charge state, then the detection sensitivity for minor changes is improved, but the measurement time increases
Solution Approach 1:
The patent employs periodic charge transfers from the sensor element to the holding capacitor, followed by periodic timer measurements. This rhythmic sequence of charge transfer and temporal evaluation creates an efficient measurement cycle. The periodic nature allows the system to accumulate charge information over multiple cycles while maintaining a predictable and optimized measurement rhythm, balancing accuracy requirements with time efficiency.
Solution Approach 2:
The holding capacitor serves multiple functions: it accumulates charge from repeated sensor element transfers, stores the accumulated charge state for temporal evaluation, and provides a voltage signal for the timer measurement. This multi-functionality allows the system to perform repeated charge transfers for sensitivity improvement without requiring separate components for each function, thereby reducing overall measurement time and system complexity.
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 approach enables precise and quick detection of changes in capacitance, enhancing the sensitivity and speed of the detection process while reducing the complexity and cost of the measurement system.
Implementation Method 1
the sensor element can provide a variable capacitance that is specific to these changes in the environment
Implementation Method 2
the amount of charge can be transferred to a holding capacitor, and the correspondingly influenced voltage on the holding capacitor can be recorded
Data Source
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AI summary
The invention relates to an arrangement (10) for detection at a door handle (4) of a vehicle (1), in particular for detecting an activation action at the door handle (4), comprising: - at least one sensor element (20.1) for detecting a change in the environment of the sensor element (20.1), - a control device (50) for repeatedly determining at least one parameter of the sensor element (20.1) specific for detection, in order to carry out the detection at the door handle (4), - an electrical holding arrangement (51) which is connected to the at least one sensor element (20.1) for repeated charge transfer in order to determine the parameter on the basis of a change in the charge state of the holding arrangement (51), wherein a time detection arrangement (60) of the control device (50) is connected to the holding arrangement (51) in order to evaluate the holding arrangement (51) over time in order to determine the charge state.