Three-State CAN FD Light Driver for Shared Bus Reliability
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Solution Overview
Problem
The high cost and complexity of providing a CAN FD transceiver for each processing unit in a system, especially in scenarios where multiple processing units need to communicate on a CAN FD Light bus, pose a significant challenge in automotive and other applications.
Innovation Solution
A processing system with a CAN FD Light controller that includes a three-state driver circuit and combinational logic to manage the transmission and reception of CAN FD Light frames without the need for a separate transceiver for each processing unit, using a shared transmission line and pull-up resistance to enable efficient data exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a CAN FD transceiver is provided for each processing unit, then reliable data transmission is achieved, but system cost and complexity increase significantly
Solution Approach 1:
The patent merges multiple CAN FD transceiver functions into a single shared transceiver that is time-multiplexed across multiple processing units. The transceiver is shared between a first processing unit and a second processing unit, with a controller managing arbitration and signal conditioning to enable reliable communication without requiring individual transceivers for each unit, thus reducing system complexity while maintaining transmission reliability.
2Device complexity
If a shared transceiver is used among multiple processing units, then cost and complexity are reduced, but signal distortion and reliability issues arise
Solution Approach 1:
The patent introduces an intermediary controller that acts as a mediator between multiple processing units and the shared transceiver. This controller implements arbitration logic to manage access to the shared transceiver, conditions signals to prevent distortion, and ensures reliable data transmission by coordinating the timing and sequence of communications between processing units and the transceiver.
3Quantity of substance
If multiple processing units share a transmission line, then component count is reduced, but signal distortion increases
Solution Approach 1:
The controller serves as an intermediary that conditions signals before they are placed on the shared transmission line, preventing signal distortion caused by direct connections from multiple processing units. The intermediary manages signal levels, timing, and arbitration to maintain signal integrity while enabling multiple units to share the transmission line with reduced component count.
Data Source
AI summary
In an embodiment a processing system includes a sub-circuit including a three-state driver circuit, wherein the three-state driver circuit has a combinational logic circuit configured to monitor logic levels of a first signal and a second signal, and selectively activate one of the following switching states as a function of the logic levels of the first signal and the second signal: in a first switching state, connect the transmission terminal to the positive supply terminal by closing the first electronic switch, in a second switching state, connect the transmission terminal to the negative supply terminal by closing the second electronic switch, and in a third switching state, put the transmission terminal in a high-impedance state by opening the first electronic switch and the second electronic switch.