CAN Transceiver Bus Level Acceleration via Current Drive
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Solution Overview
Problem
The existing CAN bus system is limited by its bit rate, which restricts the transmission speed of larger data blocks due to fixed signal propagation speed and intrinsic processing times, making it inefficient for real-time data transmission.
Innovation Solution
A modified transceiver device that accelerates the setting of the recessive bus level by driving a suitable electrical current between bus lines, allowing for faster data transmission by modifying the current intensity during specific states and switching conditions, and optionally reporting back to the controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the bit rate is increased by reducing the duration of individual bits, then the data transmission speed is improved, but the signal propagation speed and intrinsic processing times prevent further acceleration
Solution Approach 1:
The patent applies preliminary action by pre-charging the bus lines to the dominant level before the actual data transmission begins. The output stage is configured to charge the bus lines in advance, so that when transmission is needed, the bus is already in the correct state, eliminating the need for slow sequential bit-by-bit arbitration and reducing intrinsic processing time.
Solution Approach 2:
The patent changes the electrical parameters of the bus system by introducing a third voltage level (dominant level with higher voltage than standard CAN) and modifying the output stage to actively charge the bus lines. This parameter change enables faster signal propagation and reduces the time required for bus level changes, thereby increasing data transmission speed without being limited by conventional processing times.
2Speed
If the bus system extension is reduced to achieve shorter bit lengths, then the signal propagation time is decreased, but the bus system architecture becomes more complex
Solution Approach 1:
Instead of reducing the physical extension of the bus system, the patent changes the electrical parameters by introducing a dominant voltage level that is higher than the standard CAN dominant level. This parameter change allows the bus to be charged faster without requiring a smaller physical bus, thereby increasing signal propagation speed while maintaining the existing bus architecture and avoiding added complexity.
3Loss of time
If additional current is driven to accelerate bus level changes, then the data transmission time is reduced, but the energy consumption increases
Solution Approach 1:
The patent applies periodic action by using the existing CAN arbitration protocol to control when the accelerated charging mode is activated. The output stage charges the bus lines only during specific periods when arbitration is needed and the bus is in the recessive state, rather than continuously driving current. This periodic charging approach reduces energy consumption compared to continuous current driving while still achieving fast bus level changes when needed.
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 faster message transmission in CAN networks and other two-wire bus systems by reducing the time required to set the recessive bus level, improving real-time data transfer efficiency without disrupting other stations' access.
Implementation Method 1
a transmitting station accelerates the setting of the recessive bus level by driving a suitable, possibly additional, electrical current
Data Source
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AI summary
A device is proposed for connecting a bus user to a 2-wire communication bus, allowing the bus user to send messages, which are represented by a sequence of dominant and recessive bus levels in the bus lines, to other bus users connected to the bus and to receive such messages from the other bus users. The device comprises first means for setting, by driving a first electric current, a dominant bus level in the form of a first predetermined voltage difference between the two bus lines; the device is designed in such a way that the recessive bus level is set as a second predetermined voltage difference that does not necessarily differ from zero between the two bus lines, at least partially owing to the flow of a discharge current over termination resistors connected to the bus lines, and the device comprises at least one other means for setting more quickly at least one of the bus levels by driving at least one other suitable electric current at least in the event of a predeterminable or predetermined switching condition.