Sensor Circuit Short Circuit Detection via Impedance Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor circuits in automotive applications are unable to detect short circuits between wheel-speed sensors and channels effectively, especially in dynamic operational conditions, as they are designed to detect short conditions only between individual sensors and ground, and not between multiple sensors or channels, and often require a static state for accurate fault detection.
Innovation Solution
The proposed solution involves a sensor circuit that actively changes impedance by controlling a MOSFET to function as a diode, allowing for the detection of short circuits between sensors or channels by altering the operational mode and monitoring current changes, enabling the identification of unbalanced currents indicative of a short condition, even in moving vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing sensor circuits are used to detect short circuits, then detection of short conditions between individual sensors and ground is achieved, but detection of short circuits between multiple sensors or channels is not possible
Solution Approach 1:
The invention divides the detection process into multiple phases: normal operation mode and test mode. During test mode, the system segments the detection by sequentially applying test signals to individual channels while isolating others, enabling detection of shorts between any pair of channels through systematic division of the detection task
Solution Approach 2:
The invention changes the operational parameters of the sensor circuit by switching between normal operation mode and test mode. In test mode, impedance values are deliberately altered and test signals are applied, transforming the circuit's electrical characteristics to enable detection of short conditions that cannot be detected during normal operation
2Measurement precision
If sensor circuits operate in static state for fault detection, then accurate detection of short conditions is achieved, but detection in dynamic operational conditions (moving vehicles) is not effective
Solution Approach 1:
The invention makes the sensor circuit dynamic by implementing a test mode that can be activated during vehicle motion. The system dynamically switches between normal operation and test mode, and dynamically adjusts impedance values during testing, enabling effective short circuit detection regardless of whether the vehicle is stationary or moving
Solution Approach 2:
The invention employs periodic test signals during test mode to detect short circuits. By applying periodic test signals and analyzing the responses, the system can accurately detect short conditions even during dynamic vehicle operation, transforming the detection process into a periodic measurement cycle
3Reliability
If impedance is kept constant for sensor operation, then normal sensor function is maintained, but detection of unbalanced currents indicative of short conditions is not possible
Solution Approach 1:
The invention changes impedance parameters during test mode to enable detection of short circuits. By deliberately altering impedance values and applying test signals, the system creates measurable current imbalances that indicate short conditions, while maintaining constant impedance during normal operation for stable sensor function
Data Source
AI summary
A sensor circuit includes at least one signal processing circuit connectable to at least one sensor operable on a channel and configured to receive and process a periodic sensor signal therefrom the sensor circuit further includes a switching device coupled between the signal processing circuit and the at least one sensor, at least one switch coupled to the switching device and a controller connected to the at least one switch and to an output of the signal processing circuit. The controller is operable to re-configure the switching device via control of the switch and determine whether a short condition exists on the at least one sensor or channel based on the output from the signal processing circuit.