Transceiver Architecture for Bus Fault Detection and Radiation Tolerance
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Solution Overview
Problem
The existing transceivers for spacecraft communication buses, such as the CAN bus, face challenges with high voltage drops and radiation tolerance, particularly in harsh environments like geostationary orbits, and are not optimized for high current throughput, leading to inefficiencies and potential damage from fault conditions like over-currents and shorts.
Innovation Solution
A method and transceiver design that monitors current through transistors to detect fault conditions, switching to an inactive state to prevent damage without relying on reverse current bus port diodes, allowing for integration with digital circuits and radiation-tolerant processes, and includes fault detection for over-currents, under-currents, and differential voltage monitoring to prevent fault propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional CMOS processes are used for transceiver implementation, then integration with digital circuits is achieved, but high voltage drop occurs between supply voltage level and differential dominant output voltage level
Solution Approach 1:
The patent changes the voltage level parameters by introducing intermediate voltage levels (e.g., 1.8V, 2.5V, 3.3V) between the supply voltage and the differential output voltage. This allows the transceiver to operate at lower voltage levels internally while still providing the required high voltage output, thereby reducing power consumption and voltage drop while maintaining compatibility with digital CMOS circuits
Solution Approach 2:
The patent introduces intermediary voltage level conversion circuits that act as mediators between the low-voltage digital CMOS logic and the high-voltage differential bus interface. These intermediary circuits enable voltage level translation without requiring the entire transceiver to operate at high voltage, thus reducing overall power consumption while maintaining high current throughput capability
2Reliability
If separate transceivers are used for each node to ensure radiation tolerance, then reliability in harsh environments is improved, but device complexity and weight increase
Solution Approach 1:
The patent merges multiple transceiver functions into a single integrated transceiver design that can handle multiple differential bus interfaces simultaneously. This consolidated approach maintains radiation tolerance through specialized CMOS process design while reducing the overall number of discrete transceiver components, thereby decreasing device complexity and weight
Solution Approach 2:
The patent designs a universal transceiver architecture that can operate across multiple voltage levels and support various differential bus standards (e.g., CAN, LIN, FlexRay). This multi-functional design eliminates the need for separate dedicated transceivers for different protocols, reducing component count while maintaining reliability through radiation-hardened design principles
3Reliability
If reverse current bus port diodes are added to protect against fault conditions, then reliability is improved, but voltage drop increases and integration with digital circuits becomes difficult
Solution Approach 1:
The patent replaces the mechanical/passive protection diode approach with an active electronic protection mechanism using transistors and control logic. This electronic substitution enables fault detection and protection without the voltage drop penalties of diodes, while maintaining full compatibility with digital CMOS integration
Solution Approach 2:
The patent implements feedback-based fault detection circuits that continuously monitor bus conditions and automatically activate protection mechanisms when faults are detected. This active feedback approach provides reliable fault protection without requiring passive protection diodes, thereby avoiding voltage drop issues and maintaining integration compatibility with digital circuits
Data Source
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AI summary
This application relates to a method of operating a transceiver for imparting a voltage signal on a differential signaling bus, wherein the transceiver comprises an output terminal and a string of one or more transistors connected between the output terminal and a predetermined voltage level, and wherein the transceiver can be switched between an active state in which the predetermined voltage level is applied to the output terminal, and an inactive state in which the predetermined voltage level is not applied to the output terminal. The method comprises a detection step of detecting a first quantity depending on a current flowing through a first transistor in the string of transistors, a failure determination step of determining whether the detected first quantity satisfies one or more error conditions, and a control step of switching the transceiver to the inactive state if the detected first quantity is determined to satisfy at least one of the one or more error conditions. The application further relates to a transceiver for imparting a voltage signal on a differential signaling bus.