Current-Sensed Open-Drain Repeater Without Static Voltage Offset
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Solution Overview
Problem
Conventional repeaters in open-drain systems face challenges such as static offset issues, high costs due to large pull-up resistors, and inability to handle high-speed communications, which affect signal integrity and efficiency.
Innovation Solution
A repeater apparatus comprising a first port, a second port, a current detector, a transistor, and a control logic circuit, where the current detector and control logic circuit work together to eliminate the need for external pull-up resistors, reduce static voltage offset, and support high-frequency communications by determining current flow to control the transistor's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional repeaters use static offset buffers, then signal buffering is achieved, but static voltage offset is introduced that prevents downstream devices from seeing proper output low level
Solution Approach 1:
The patent removes the static offset buffer component entirely from the repeater design. Instead of using a buffer that introduces static voltage offset, the invention uses a transistor switch controlled by a control logic circuit that directly responds to current detector signals, eliminating the source of the harmful static offset while maintaining signal buffering functionality.
Solution Approach 2:
The patent introduces a control logic circuit as an intermediary between the current detector and the transistor switch. This control logic circuit processes the current detection signal and generates appropriate control signals to switch the transistor on or off, thereby mediating the signal transmission without introducing static offset and enabling proper low level output.
2Difficulty of detecting and measuring
If conventional repeaters use large pull-up resistors to detect transmission and reception, then data detection capability is achieved, but device footprint and cost increase
Solution Approach 1:
The patent replaces the mechanical/electrical component approach (large physical pull-up resistors) with an electronic detection approach using a current detector circuit. The current detector uses transistor-based current sensing that can detect data transmission and reception through current flow measurements without requiring large physical resistors, thereby reducing device footprint while maintaining detection capability.
3Device complexity
If conventional repeaters are designed for basic communication speeds, then circuit simplicity is maintained, but ability to handle high-speed communications is lost
Solution Approach 1:
The patent implements dynamic operation by using a transistor switch that can rapidly transition between on and off states based on control signals from the control logic circuit. This dynamic switching capability allows the repeater to respond to high-speed communication signals, supporting I2C fast mode and fast-mode plus speeds, while the overall circuit topology remains relatively simple and elegant.
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
This solution reduces the repeater's footprint and cost, improves signal integrity, and enables support for high-frequency communications like I2C standard, fast mode, and fast-mode plus speeds, while eliminating the need for power sequencing and static voltage offset.
Implementation Method 1
A current detector input of the current detector is coupled to the first port
Implementation Method 2
A transistor channel electrode of the transistor is coupled to the second port. A control logic circuit output of the control logic circuit is coupled to a transistor control electrode of the transistor
Data Source
AI summary
This disclosure generally relates to repeaters, and, in particular, repeaters for open-drain systems. In one embodiment, an apparatus comprises a first port, a second port, a current detector, a transistor, and a control logic circuit. A current detector input of the current detector is coupled to the first port. A transistor channel electrode of the transistor is coupled to the second port. A control logic circuit input of the control logic circuit is coupled to the current detector output, and a control logic circuit output of the control logic circuit is coupled to a transistor control electrode of the transistor.