Bus Voltage Slew Rate Switching for EMI-Safe Vehicle Communication
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Solution Overview
Problem
Existing in-vehicle communication devices using pulse-width modulation signals as line codes face challenges in controlling the slew rate of bus voltage, leading to potential EMI noise generation.
Innovation Solution
A communication device with a master node and a slave node that can switch between two states to control the slew rate of the bus voltage, either through feedback input of the bus voltage or a predetermined control signal, to suppress EMI noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If feedback control of bus voltage slew rate is implemented, then EMI noise is suppressed, but device complexity increases
Solution Approach 1:
The patent implements dynamic slew rate control by switching between two operational states: a first state where feedback control actively regulates the slew rate to suppress EMI noise, and a second state where slew rate control is relaxed to reduce communication latency. This dynamic adaptation resolves the contradiction by applying complex control only when necessary for noise suppression, rather than continuously.
Solution Approach 2:
The patent changes the control parameter (slew rate) based on communication timing requirements. By adjusting the slew rate parameter dynamically between two states, the system achieves EMI noise suppression during critical transmission phases while maintaining acceptable communication performance during other phases, thus resolving the complexity-performance tradeoff.
2Reliability
If slew rate control is implemented to suppress EMI noise, then communication stability is improved, but communication latency increases
Solution Approach 1:
The patent applies periodic switching between feedback control state and relaxed control state, rather than continuous feedback control. This periodic action allows the system to achieve communication stability during controlled phases while reducing average latency by allowing faster transitions during relaxed phases, thus resolving the contradiction between reliability and time loss.
Solution Approach 2:
The system dynamically adapts its control strategy based on communication phase requirements, switching between aggressive slew rate control for stability and relaxed control for speed. This dynamic behavior resolves the contradiction by optimizing for different objectives at different times rather than compromising constantly.
Data Source
AI summary
A communication device includes a communication line, a master node, and a slave node. At least one of the master node or the slave node is configured to switch to either a first state in which feedback input of a bus voltage of the communication line is received to control a slew rate of the bus voltage to a desired value, and a second state in which input of a predetermined control signal is received to control the slew rate of the bus voltage to a desired value.