Bus Transceiver Edge Shaping for EMI and Interference Immunity
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Solution Overview
Problem
Unshielded bus systems face high-frequency interference radiation due to low edge steepness of signal outputs, leading to increased sensitivity to coupled-in interference signals, as slow signal edges cause repeated switching between logic levels and interference sensitivity in transmitter/receiver components.
Innovation Solution
A method and transmitter/receiver component that dynamically adjust signal edge steepness based on detected high-frequency interference levels, increasing steepness during high interference and decreasing it during low interference, using controllable current sources and a delay unit to maintain timing specifications and reduce interference-induced switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the edge steepness of signal output is decreased to reduce interference radiation, then high-frequency interference radiation is reduced, but sensitivity to coupled-in high-frequency interference signals increases
Solution Approach 1:
The patent implements dynamic adjustment of the edge steepness parameter based on detected interference conditions. The system monitors for high-frequency interference signals and automatically increases edge steepness when interference is detected, while maintaining lower edge steepness during normal operation to minimize radiation. This dynamic adaptation resolves the contradiction by making the edge steepness variable rather than fixed.
Solution Approach 2:
The patent changes the physical parameter of edge steepness based on operating conditions. By detecting the presence of high-frequency interference signals and adjusting the edge formation circuit accordingly, the system transitions between different edge steepness states. This parameter change allows the system to optimize both radiation reduction and interference immunity under different conditions.
2Reliability
If the edge steepness is increased to prevent multiple switching in receiver, then interference immunity is improved, but interference radiation increases
Solution Approach 1:
The system dynamically adjusts edge steepness based on detected interference conditions. During normal operation, lower edge steepness is maintained to minimize radiation. When high-frequency interference is detected, the system automatically increases edge steepness to prevent multiple switching in the receiver, thus improving reliability only when necessary.
Solution Approach 2:
The system continuously monitors for interference signals and periodically adjusts the edge steepness parameter based on the detected conditions. This periodic detection and adjustment ensures that high edge steepness is applied only during periods when interference is present, rather than continuously, thereby reducing overall radiation while maintaining interference immunity 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
The solution effectively reduces interference radiation and sensitivity by preventing multiple switching in receivers, ensuring high bus system immunity to high-frequency interference by adjusting edge steepness in real-time, thus maintaining system timing and reducing interference-induced errors.
Implementation Method 1
a high-frequency interference detector which detects a high-frequency interference level on the bus line
Implementation Method 2
a first controllable current source which is looped between a supply voltage and a gate terminal of the driver transistor, and a second controllable current source which is looped between the gate terminal of the driver transistor and a reference potential
Data Source
AI summary
A method is provided for edge formation of signals and transmitter/receiver component for a bus system. A transmitter/receiver component for a bus system comprises a driver transistor, which is to be looped between a bus line of the bus system and a reference potential and is used to output signals on the bus line, a control unit for the driver transistor, a high-frequency interference detector, which is configured in such a way that it detects a high-frequency interference level on the bus line of the bus system, whereby the control unit is configured in such a way that it controls the driver transistor, depending on the detected high-frequency interference level, in such a way that an edge steepness of the output signals increases when the high-frequency interference level on the bus line increases, and an edge steepness of the output signals decreases when the high-frequency interference level on the bus line decreases.