Interface Circuit with Variable Output Swing and Open Termination
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Solution Overview
Problem
Existing interface circuits face limitations in flexibility due to the need for matched impedances and fixed voltage swings, which restrict their ability to handle impedance mismatches and varying signal strengths, especially in short-distance communications.
Innovation Solution
The development of interface circuits that can transmit signals with customizable variable output swings and open termination modes, allowing for impedance mismatches and flexible voltage configurations, enabling efficient signal transmission even when impedances are not matched and voltage swings deviate from standard ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If matched impedances are used between transmitter and receiver circuits, then signal transmission reliability is improved, but device flexibility and adaptability deteriorate
Solution Approach 1:
The patent implements dynamic impedance control by allowing the transmitter output impedance to be adjusted based on receiver feedback. The impedance matching is no longer fixed but adapts dynamically to the actual transmission conditions and receiver requirements, resolving the contradiction between maintaining reliable signal transmission and providing device flexibility.
Solution Approach 2:
The patent changes the impedance parameter from a fixed matched value to a variable parameter that can be adjusted according to transmission distance, frequency, and receiver sensitivity. This allows the system to maintain optimal signal integrity while adapting to different application scenarios, thus improving both reliability and flexibility.
2Reliability
If fixed predetermined voltage swings are employed, then communication reliability between transmitter and receiver is improved, but adaptability to varying signal strength requirements deteriorates
Solution Approach 1:
The patent implements dynamic voltage swing adjustment where the transmitter can modify its output voltage amplitude based on receiver feedback and transmission conditions. This dynamic control allows the system to maintain reliable communication at different distances and frequencies while adapting to varying signal strength requirements, resolving the contradiction between fixed reliability and flexible adaptability.
3Loss of energy
If impedance matching is enforced, then signal loss and reflections are reduced, but ease of operation and configuration flexibility deteriorate
Solution Approach 1:
The patent implements automatic impedance matching where the transmitter automatically adjusts its output impedance based on receiver feedback without requiring manual configuration. This self-adjusting mechanism maintains optimal signal transmission with minimal reflections and losses while eliminating the complexity of manual impedance matching, thus improving both energy efficiency and ease of operation.
Solution Approach 2:
The patent uses feedback from the receiver to the transmitter to automatically adjust impedance matching parameters. The receiver measures signal quality and feeds this information back to the transmitter, which then adjusts its output impedance accordingly. This closed-loop control maintains minimal signal loss and reflections while requiring no manual configuration, resolving the contradiction between energy efficiency and operational ease.
Data Source
AI summary
An interface circuit includes a pre-driver coupled convert a single-ended signal to an intermediate differential signal. An output driver is coupled to convert the intermediate differential signal to an output differential signal having a variable output swing responsive to a mode select signal and a second supply voltage. A replica bias circuit is coupled to receive a first supply voltage, the mode select signal, and an open termination enable signal to generate a bias signal. An internal regulator is coupled to receive the bias signal and the first supply voltage to supply the second voltage to the output driver in response to the bias signal. An open termination circuit is coupled to an output of the output driver, and is coupled to receive the open termination enable signal to couple an internal load to the output of the output driver in response to the open termination enable signal.