Transceiver Circuit Switching for Single-Ended and Differential Lines
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Solution Overview
Problem
The transmission of single-ended signals via transmission lines results in increased energy consumption and potential crosstalk due to impedance matching and terminating resistances, which can exceed the capacity of amplifiers and impair differential signal transmission, especially when high voltage levels are involved.
Innovation Solution
A transmit and receive circuit design that includes series-connected impedance matching and terminating resistances with a switch in between, allowing for seamless conversion between single-ended and differential signal transmission without power loss or parasitic capacitance interference, using level and coupling resistances to maintain signal integrity and symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If impedance matching and terminating resistances are used for single-ended signal transmission, then signal transmission is enabled, but energy consumption increases and current flow exceeds amplifier capacity
Solution Approach 1:
The patent applies dynamics by making the impedance matching resistance and terminating resistance dynamically switchable. A switch element is introduced that can connect or disconnect these resistances based on the signal type being transmitted. When single-ended signals are transmitted, the switch connects the resistances to enable proper signal levels. When differential signals are transmitted, the switch disconnects the resistances to avoid excessive current flow and energy consumption, thus adapting the circuit configuration to the transmission mode.
Solution Approach 2:
The patent changes the electrical parameters of the transmission circuit by introducing a switch that can alter the resistance values seen by the transmission lines. The switch element changes the circuit state between having impedance matching and terminating resistances connected (for single-ended mode) and having them disconnected (for differential mode). This parameter change allows the same physical circuit to support two different transmission modes with appropriate electrical characteristics for each mode.
2Loss of energy
If switches are added to separate differential circuit parts for single-ended signal transmission, then current flow is reduced, but parasitic capacitances and reflections are introduced that impair differential signal quality
Solution Approach 1:
The patent uses a dynamic switching mechanism that controls the connection of impedance matching and terminating resistances. The switch is designed to be positioned and controlled such that it only affects single-ended signal paths while leaving differential signal paths intact. When switching between transmission modes, the transition is managed to minimize parasitic effects, and the switch location is chosen to avoid introducing significant parasitic capacitances into the high-frequency differential signal path.
3Adaptability or versatility
If additional switches and line branches are provided for signal separation, then single-ended and differential transmissions are enabled, but device complexity increases
Solution Approach 1:
The patent merges the functions of single-ended and differential signal transmission into a single integrated circuit structure. Instead of providing completely separate transmission paths with independent components, the invention combines both capabilities in one circuit by using a shared transmission line pair with a single switch element that controls the connection of impedance matching and terminating resistances. This merging approach enables the circuit to adapt to different transmission modes without duplicating components, thus reducing overall device complexity while maintaining versatility.
Data Source
AI summary
A transmit circuit for sending and/or receiving at least one single-ended signal and for sending a differential signal on two transmission lines, including: a differential amplifier for sending signal parts of a differential signal via the two transmission lines, two impedance matching resistances that are situated between the transmission lines, connected in series, for the impedance matching of the differential amplifier; a switch that is connected in series between the impedance matching resistances; at least one single-ended transmit amplifier for sending or receiving a single-ended signal via an associated one of the transmission lines, each of the at least one single-ended transmit amplifiers being connected to a terminal of the switch that is connected, via the corresponding impedance matching resistance to the associated transmission line.