Crash Switch Circuit for Noise-Tolerant Signal Hold
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Solution Overview
Problem
Existing crash detection systems face challenges in quickly transmitting crash signals to safety apparatuses without a separate power source, particularly in scenarios where power issues or noise interference occur, such as chattering or ripple noise.
Innovation Solution
A crash switch circuit is designed to operate without a separate power source, utilizing a diode, resistors, and capacitors to detect crash signals and maintain a reference voltage level for a defined time, ensuring reliable signal transmission and noise tolerance, and includes a level converter to adjust signal levels for the main control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate power source is used for the crash detection circuit, then the reliability of crash signal detection is improved, but the device complexity and cost increase
Solution Approach 1:
The crash detection circuit uses the battery pack's own power system to operate the detection circuit. The emitter is connected to the positive terminal voltage of the battery pack, and the circuit operates using the battery's existing power structure without requiring an independent power source, thereby reducing complexity while maintaining detection reliability
Solution Approach 2:
The battery pack's power system serves dual purposes: it powers both the normal battery management operations and the crash detection circuit simultaneously. The existing battery terminals and voltage regulation mechanisms are utilized for crash detection, eliminating the need for separate power infrastructure
2Object-affected harmful factors
If noise filtering components are added to the crash detection circuit, then the noise tolerance is improved, but the device complexity increases
Solution Approach 1:
The circuit converts the battery's ripple noise characteristics into a useful reference signal. By using the battery's own voltage ripple as the reference voltage for the comparator, the circuit transforms the harmful noise into a beneficial feature that actually helps in crash detection, eliminating the need for separate noise filtering components
Solution Approach 2:
The capacitor connected to the emitter acts as an intermediary element that filters high-frequency noise while allowing the DC component and useful voltage variations to pass through. This single capacitor provides noise tolerance without requiring a complex array of filtering components
3Measurement precision
If the crash signal transmission is delayed for verification, then the measurement precision is improved, but the speed of safety response deteriorates
Solution Approach 1:
The circuit performs preliminary verification of the crash signal by comparing it against the reference voltage and checking for sustained voltage levels before triggering the safety response. This preliminary check ensures signal accuracy while maintaining fast response by avoiding post-detection verification delays
Solution Approach 2:
The circuit rushes through the verification process by using a simple voltage threshold comparison rather than complex multi-stage verification. The comparator directly compares the crash signal with the reference voltage and immediately triggers the output transistor when the threshold is exceeded, eliminating unnecessary verification steps while maintaining sufficient accuracy
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 enables the crash switch circuit to effectively control safety-related circuits even during power issues, preventing malfunctions and noise interference, thereby ensuring timely and accurate crash signal transmission for safety operations.
Implementation Method 1
the diode may be a Zener diode with a breakdown voltage value
Implementation Method 2
a first resistor and a capacitor connected in parallel with each other between the emitter and the first node
Implementation Method 3
a first switch including: an emitter configured to be supplied with a positive terminal voltage of a battery pack; a collector configured to output a crash output signal; and a base connected with a first node
Data Source
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AI summary
A crash switch circuit includes: a first switch including: an emitter to be supplied with a positive terminal voltage of a battery pack; a collector to output a crash output signal; and a base connected with a first node; a first resistor and a capacitor connected in parallel with each other between the emitter and the first node; and a diode including an anode to be supplied with a crash input signal from a crash sensor, and a cathode connected with the first node.