CAN Transceiver Self-Test Switching for Bus-Safe Operability Checks
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Solution Overview
Problem
Testing the operability of a CAN transceiver in a CAN bus network results in significant load and time expenditure, affecting regular communication and requiring arbitration, which is undesirable.
Innovation Solution
A CAN transceiver design with a test unit that allows operability testing without interfering with the CAN bus network by using a test unit to transition between states, enabling testing through internal signal paths and reduced voltage signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a CAN transceiver is tested using traditional testing methods, then the operability can be verified, but the CAN bus network is disrupted and significant load and time expenditure occurs
Solution Approach 1:
The transceiver is divided into separate functional components: a transmitter, a receiver, and a test unit. The test unit can be independently activated to test specific components without affecting the entire transceiver system or the CAN bus network, allowing reliable testing while maintaining communication efficiency during normal operation.
Solution Approach 2:
The test unit acts as an intermediary component that enables testing operations. It includes a test signal generator and comparator that can inject test signals into the transmitter or receiver without disrupting normal CAN bus communication. The intermediary allows verification of operability while maintaining system productivity through isolated testing operations.
2Reliability
If traditional testing methods are used, then the transceiver operability can be confirmed, but arbitration is required and time expenditure increases
Solution Approach 1:
The test unit is configured to perform testing operations independently without requiring arbitration on the CAN bus. The test signal generator can directly inject test signals into the transmitter or receiver components, enabling preliminary verification of operability before normal communication begins, thus eliminating time loss associated with arbitration procedures.
Solution Approach 2:
The test unit enables the transceiver to test its own operability through self-diagnostic capabilities. The test signal generator and comparator work together to verify transmitter and receiver functionality without requiring external testing equipment or arbitration with other bus devices, significantly reducing testing time while confirming reliability.
3Reliability
If the test unit is activated continuously, then operability testing can be performed, but the CAN bus communication is disrupted
Solution Approach 1:
The test unit is designed with dynamic state control, allowing it to transition between active testing mode and inactive communication mode. The controller can activate the test signal generator and comparator only when needed for verification, and deactivate them during normal CAN bus operation. This dynamic behavior enables reliable testing capability while maintaining ease of bus communication during regular operations.
Solution Approach 2:
The test unit operates periodically rather than continuously. The controller can schedule testing operations during idle periods or designated time windows, activating the test signal generator and comparator only when necessary. This periodic operation pattern allows operability verification without disrupting CAN bus communication during active data transmission periods, maintaining both testing capability and communication ease.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and rapid operability testing of the CAN transceiver without disrupting bus communication, reducing load and time expenditure.
Implementation Method 1
the reducer is configured to generate an output voltage for the receiver based on a CAN Bus voltage from the CAN Bus interface, such that the output voltage is less than one tenth, one twentieth, or one thirtieth of the CAN Bus voltage
Data Source
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AI summary
The present disclosure relates to a controller area network, CAN, transceiver, comprising: a transmit data, TXD, interface, a receive data, RXD, interface, a CAN Bus interface, a transmitter, a reducer, and a test unit, wherein a transmitter input of the transmitter is coupled to the TXD interface for receiving a TXD signal, wherein a transmitter output of the transmitter is coupled to a test unit input of the test unit and a first test unit output of the test unit is coupled to the CAN Bus interface, wherein the CAN Bus interface is coupled to a receiver input of the receiver via the reducer, wherein a receiver output of the receiver is coupled to the RXD interface, wherein a second test unit output of the test unit is coupled to the receiver input of the receiver, wherein the test unit is configured to change from a first state to a second state, and vice versa, wherein the test unit is configured, in the first state, to couple the test unit input to the first test unit output and to decouple the test unit input from the second test unit output, wherein the test unit is configured, in the second state, to decouple the test unit input from the first test unit output and to couple the test unit input to the second test unit output. The present disclosure also relates to a method for the CAN transceiver.