Vehicle Electrical Diagnostic System Multiplexer Malfunction Detection
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Solution Overview
Problem
Current diagnostic systems for vehicle electrical systems lack effective mechanisms to detect and respond to malfunctions in analog multiplexers, which can lead to inefficient operation or failure in transitioning the contactor to an open position.
Innovation Solution
A diagnostic system that includes high side and low side voltage/current measuring circuits, analog multiplexers, and a microcontroller to generate signals for transitioning the contactor to an open operational position by detecting malfunctions in the multiplexers through voltage and current value analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If analog multiplexers are used to share measurement circuits between multiple inputs, then device complexity is reduced, but reliability deteriorates due to potential malfunction of the multiplexers themselves
Solution Approach 1:
The system implements a diagnostic routine that continuously monitors the operational status of analog multiplexers by analyzing voltage and current measurements. When a malfunction is detected in either multiplexer, the system provides feedback to the microcontroller, which then commands the contactor to transition to an open position, ensuring safety while maintaining the simplified measurement architecture
Solution Approach 2:
The diagnostic system performs preliminary detection of multiplexer malfunctions before they can cause harmful effects. By continuously monitoring voltage levels and current measurements through the multiplexers and detecting anomalies in advance, the system prevents potential failures from impacting contactor operation, thus maintaining reliability without increasing complexity
2Reliability
If diagnostic monitoring of multiplexer status is implemented, then reliability is improved, but device complexity increases due to additional monitoring circuits
Solution Approach 1:
The existing high side voltage measuring circuit and low side current measuring circuit are made multi-functional by using them not only for normal measurement purposes but also for diagnostic monitoring of multiplexer status. The microcontroller analyzes the same voltage and current signals to detect multiplexer malfunctions, eliminating the need for separate dedicated diagnostic circuits and thus improving reliability without significantly increasing complexity
Data Source
AI summary
A diagnostic having an analog-to-digital converter that is electrically coupled to an output port of a first analog multiplexer and an output port of a second analog multiplexer is provided. The analog-to-digital converter receives the high side voltage level signal and the low side current level signal at first and second times, respectively, and outputs a high side voltage value and a low side current value, respectively, based on the high side voltage level signal and the low side current level signal, respectively, that are received by a microcontroller. The microcontroller commands a high side driver circuit and a low side driver circuit to transition a contact of the contactor to an open operational position when the first analog multiplexer is malfunctioning based on the high side voltage value.