Daisy-Chain Sensor Interface ASICs for Single ECU Input
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Solution Overview
Problem
Existing communication systems for transmitting sensor values from multiple sensing sources to a control unit require multiple inputs at the control unit, increasing complexity and wiring costs, and necessitate synchronized clock frequencies and handshaking circuitry, which is not economically attractive for user-specific applications.
Innovation Solution
A communication system where a chain of sensor interface devices transmit autonomous sensor data to a control unit using the SENT protocol, allowing each sensor to operate at its own clock frequency without synchronization, and combining multiple sensor values into a single input, enabling user-specific ASIC development and reduced wiring costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors are connected to a control unit using traditional methods, then each sensor can transmit its data independently, but the number of inputs at the control unit increases, increasing device complexity and wiring costs
Solution Approach 1:
Multiple sensor data streams are merged into a single serial communication channel. The patent implements a daisy-chain topology where sensor data from multiple sources are combined and transmitted through one input to the control unit, eliminating the need for multiple separate inputs while maintaining independent sensor operation
Solution Approach 2:
A single control unit input is designed to handle multiple sensor data streams universally. The input interface is configured to accept and process data from N different sensing sources through a standardized serial protocol, making the control unit adaptable to various sensor configurations without requiring dedicated inputs for each sensor
2Reliability
If sensors are synchronized using a common clock line and handshaking circuitry, then data transmission can be coordinated, but the wiring complexity and cost increase significantly
Solution Approach 1:
The complex synchronization and handshaking circuitry is extracted and eliminated from the system. The patent uses autonomous asynchronous transmission where each sensor operates independently without requiring clock lines or handshaking signals, simplifying the wiring while maintaining reliable data transmission through protocol-level coordination
Solution Approach 2:
Each sensor autonomously manages its own data transmission without external coordination. The sensors self-regulate their transmission timing and format using the asynchronous unidirectional protocol, eliminating the need for external clock synchronization and handshaking mechanisms while ensuring reliable communication
Data Source
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AI summary
A communication system for transmitting sensor values to an ECU is disclosed. The communication system comprises a chain of ASICs (sensor interface devices). To each ASIC one or more sensors are coupled. All sensors connected to an ASIC are measured by said ASIC to obtain sensor values for transmission via a SENT stream in the direction of an ECU. An ASIC is further able to read and decode a SENT stream from a previous ASIC in the chain. The ASIC combines its own measurements with the measurements received via the SENT stream to one SENT output stream carrying the sensor values of all sensors connected to said ASIC and all previous ASIC in the chain for transmission to a subsequent ASIC in the chain or the ECU. Only one SENT-input is needed at the ECU to receive measurements from multiple sensors, wherein the number of sensors can easily be changed.