Dual-RC Voltage Drop Detection for Fast Vehicle Ignition Sensing
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Solution Overview
Problem
Existing on-board diagnostic systems lack an efficient method to detect instantaneous voltage drops, which is crucial for determining vehicle ignition and other operational states, often relying on slower and less timely methods that do not accurately capture the moment of voltage change.
Innovation Solution
A detection circuit comprising two RC circuits with different resistance ratios and capacitances, connected to a comparator and a determination unit, which differentiates voltage drops by inverting the comparator signal, allowing for timely detection of instantaneous voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage detection methods are used, then the system can monitor voltage levels, but the detection response is slow and cannot accurately capture instantaneous voltage changes
Solution Approach 1:
The patent divides the voltage detection function into two separate RC circuits with different time constants (one with larger resistance ratio and smaller capacitance for fast response, another with smaller resistance ratio and larger capacitance for slow response). This segmentation allows each circuit to specialize in detecting different aspects of voltage changes, with the fast circuit capturing instantaneous drops and the slow circuit providing context, thereby resolving the contradiction between detection speed and accuracy.
2Measurement precision
If complex detection circuits are designed to improve detection accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent merges two RC circuits with different time constants into a single detection system that feeds into one comparator. This combining approach allows the system to leverage the advantages of both fast and slow response circuits without requiring separate complete detection pathways, thereby improving measurement precision while controlling device complexity and cost.
Solution Approach 2:
The patent changes the parameters (resistance ratios and capacitances) of the RC circuits to create different time constants. By carefully selecting these parameters, the system achieves both fast response for instantaneous detection and sufficient accuracy, avoiding the need for more complex circuit architectures.
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
Enables timely and accurate detection of instantaneous voltage drops, improving the timeliness and accuracy of determining vehicle ignition and other operational states, with a simple and cost-effective circuit design.
Implementation Method 1
two RC circuits, a comparator and a determination unit; each RC circuit comprises a first resistor, a second resistor and an energy storage capacitor
Data Source
AI summary
A detection circuit for instantaneous voltage drop and an on-board diagnostic system. The detection circuit comprises two RC circuits, each of the RC circuits comprises a first resistor, a second resistor, and an energy storage capacitor; a first end of the first resistor is used for receiving a to-be-detected voltage, and a second end thereof is connected to a first end of the second resistor; the energy storage capacitor is connected in parallel with the second resistor; the first end of the second resistor forms an output end of the RC circuit, and the output end is connected to an input end of the comparator; an output end of the comparator is connected to the determination unit; in the two RC circuits, the resistance ratios of the second resistors to the first resistors are different, the capacitances of the energy storage capacitors are different.