Capacitively Coupled Transceiver Interface With Switchable Termination
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Solution Overview
Problem
In communication systems with transceivers connected by capacitively coupled transmission lines, existing switchable termination resistance solutions fail to optimize power consumption while maintaining low common mode voltage, especially under high electromagnetic interference conditions.
Innovation Solution
A transceiver design incorporating a switchable termination resistance circuit with series connected resistors and a capacitor, allowing the control module to disconnect the termination resistance during signal transmission, thereby reducing power consumption and minimizing common mode voltage through a split resistance arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the termination resistance is connected at the transmitter side during signal transmission, then the reflections along the transmission line are reduced, but the power consumption of the transmitter increases
Solution Approach 1:
The termination resistance is made dynamically switchable rather than fixed. The control module switches the termination resistance connection state based on transmission phase: disconnected during differential voltage application (first and second phases) to reduce power consumption, and connected during zero differential voltage phase (third phase) to reduce reflections. This dynamic adjustment resolves the contradiction between maintaining signal quality and reducing power consumption.
2Use of energy by moving object
If the termination resistance is disconnected during transmission phases, then the power consumption is reduced, but the common mode voltage increases under electromagnetic interference
Solution Approach 1:
The control module performs preliminary action by switching the termination resistance to the connected state before the zero differential voltage phase (third phase) begins. This ensures that when the transmitter is most vulnerable to electromagnetic interference during the third phase, the termination resistance is already in place to suppress common mode voltage, preventing the harmful effect rather than reacting to it.
Solution Approach 2:
The termination resistance is periodically switched based on the transmission protocol phases. During active transmission phases (first and second phases), it is disconnected to save power. During the idle/recovery phase (third phase), it is connected to suppress interference. This periodic switching pattern optimizes both power consumption and electromagnetic compatibility throughout the transmission cycle.
3Use of energy by moving object
If a switchable termination resistance is implemented in capacitively coupled transmission lines, then the power consumption is optimized, but the design complexity increases due to limited gate voltage of MOSFETs and high electromagnetic interference
Solution Approach 1:
The control module acts as an intermediary that manages the switching of termination resistance in capacitively coupled transmission lines. It coordinates the switching actions with the transmission protocol and handles the complexities of gate voltage limitations and electromagnetic interference, allowing the rest of the system to operate with simplified design assumptions while still achieving power optimization.
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 achieves a substantial reduction in power consumption and improved electromagnetic compatibility (EMC) robustness, meeting stringent standards for bulk current injection interference while maintaining low common mode voltage levels.
Implementation Method 1
a capacitively coupled transmission line communication system
Implementation Method 2
a termination resistance at each transceiver serves to reduce reflections along the transmission line
Data Source
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AI summary
The disclosure relates to a transceiver physical layer interface. Example embodiments include a transmission line transceiver (401) comprising: first and second terminals (406a, 406b); a control module (416); an amplifier module (414) connected between the control module (416) and the first and second terminals (406a, 406b); a switchable termination resistance circuit (408, 410) connected between the first and second terminals (406a, 406b), the switchable termination resistance circuit (408, 410) comprising a termination resistance (408) connected in series with a switch (410) controllable by the control module (416); a pair of series connected resistors (418a, 418b) connected between the first and second terminals (406a, 406b); a capacitor (420) connected between a node (423) connecting the pair of series connected resistors (418a, 418b) and a common node (422), wherein the control module (416) is configured to open the switch (410) to disconnect the termination resistance (408) during transmission of a signal via a transmission line (403) capacitively connected to the first and second terminals (406a, 406b).