Single-Pin Speed Sensor Multiplexing for Output and Diagnostics
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Solution Overview
Problem
Automotive sensors, such as crankshaft sensors, can only transmit either the output data signal or the internal diagnostic data signal at a time due to the limitation of using a single pin for data transmission, preventing simultaneous transmission of both signals.
Innovation Solution
A multiplexer is used to combine the output data signal and the internal diagnostic data signal into a single combined data signal, allowing simultaneous transmission by switching between normal and interface modes, with the multiplexer being configured as a time, current, or voltage multiplexer to achieve this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single pin is used to transmit data signals, then cost, weight, and risk of error are reduced, but only one signal (either output data or internal diagnostic data) can be transmitted at a time
Solution Approach 1:
The multiplexer switches between transmitting output data signals and internal diagnostic data signals in periodic time intervals. During normal operation, output data is transmitted; during diagnostic periods, internal data is transmitted. This time-division multiplexing allows both signals to share the single pin without permanent loss of either information type.
Solution Approach 2:
The system dynamically changes its transmission mode based on operational requirements. The multiplexer can switch between different transmission states (output data mode, diagnostic data mode) depending on the current operational context, allowing the single pin to adaptively serve multiple communication purposes.
2Device complexity
If a single pin is used for data transmission, then device complexity is reduced, but the ability to transmit multiple signals simultaneously is limited
Solution Approach 1:
The single pin is designed to perform multiple functions by incorporating a multiplexer that can route different data sources to the same transmission channel. The pin serves as both an output data transmission line and an internal diagnostic data transmission line, eliminating the need for separate pins while maintaining full functionality.
Solution Approach 2:
The patent combines the output data transmission function and internal diagnostic data transmission function into a single physical pin through the use of a multiplexer. This merging reduces the total number of pins required while preserving the ability to transmit both types of signals, thereby reducing device complexity without sacrificing versatility.
Data Source
AI summary
A speed sensor including an output data signal generator configured to generate an output data signal representing a state of a sensed element; and a multiplexer configured to multiplex the output data signal and an internal diagnostic data signal representing diagnostic data of the speed sensor into a combined data signal.