CAN Transmitter Mode Switching for High-Bit-Rate Signal Integrity
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Solution Overview
Problem
The existing CAN transceivers cause ringing issues due to their binary switching nature, which limits the data rate by disturbing the signal integrity and making it difficult to accurately detect bit states, thereby restricting the maximum possible data rate in CAN networks.
Innovation Solution
A transmitter circuit that switches between a first and second data transmission mode based on a bit rate indication field, using a full bridge operation mode in the second mode to reduce ringing by defining bits with potentials on both signal lines, allowing faster data rate transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If common CAN transceivers are used with binary switching between dominant and recessive bits, then the transceiver operation is simple, but ringing occurs that disturbs signal integrity and limits data rate
Solution Approach 1:
The patent applies dynamics by making the transceiver circuit adjustable between two different operating modes (first mode with terminating resistor for compatibility, second mode without terminating resistor for reduced ringing). This allows the system to dynamically switch circuit configurations based on communication requirements, resolving the contradiction between simple binary switching and signal integrity
Solution Approach 2:
The patent changes the circuit parameters by selectively connecting or disconnecting the terminating resistor between the first conductor and second conductor. In the first operating mode, the terminating resistor is connected to provide impedance matching. In the second operating mode, the terminating resistor is disconnected to reduce ringing effects, thereby improving signal integrity and enabling higher data rates
2Productivity
If the maximal data rate is adapted to signal integrity with ordinary CAN transceivers, then communication reliability is maintained, but the data rate is unnecessarily limited
Solution Approach 1:
The transceiver dynamically switches between operating modes based on communication requirements. The second mode enables faster bit transitions with reduced ringing for high-speed data transmission, while the first mode ensures compatibility and reliable detection in standard conditions, thus resolving the contradiction between data rate and detection accuracy
Data Source
AI summary
In various embodiments, a method for controlling the operation of a transmitter circuit is provided, the method including: detecting a state of a message field within a data message to be sent by the transmitter circuit indicating a bit rate to be used for transmission by the transmitter circuit and switching the mode of operation of the transmitter circuit from a first data transmission mode to a second data transmission mode depending on the state of the message indication field, wherein in the first data transmission mode a first circuit configured to transmit data may be used and wherein in the second data transmission mode a second circuit configured to transmit data may be used. Further, a corresponding controlling circuit is provided.