Hybrid Transmitter Common-Mode Control for Pre-Emphasis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hybrid transmitters face challenges in integrating voltage-mode and current-mode transmission schemes, particularly in supporting pre-emphasis functions for both modes, which affects signal and power integrity during high-speed transmissions.
Innovation Solution
A hybrid transmitter design incorporating a current-mode driver, a voltage-mode driver, and an auxiliary driver, along with a common-mode sense circuit that includes a digital-to-analog converter, counter, and comparator, to enable both voltage-mode and current-mode transmissions and pre-emphasis functions by controlling common-mode voltages to ensure balanced signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage-mode transmission is used, then signal integrity is improved, but power integrity deteriorates due to shoot-through current during switching
Solution Approach 1:
The transmitter is divided into two separate transmission paths: a voltage-mode driver for signal-critical channels and a current-mode driver for power-critical channels. This segmentation allows each path to be optimized for its specific requirement, resolving the contradiction between signal integrity and power integrity by eliminating the need to compromise either aspect.
2Loss of energy
If current-mode transmission is used, then power integrity is improved, but signal integrity deteriorates
Solution Approach 1:
The transmitter is divided into two separate transmission paths: a voltage-mode driver for signal-critical channels and a current-mode driver for power-critical channels. This segmentation allows each path to be optimized for its specific requirement, resolving the contradiction between signal integrity and power integrity by eliminating the need to compromise either aspect.
3Productivity
If pre-emphasis circuit is added to improve signal swing, then transmission performance is improved, but device complexity increases due to separate circuits for voltage and current modes
Solution Approach 1:
A single auxiliary driver is designed to function in multiple modes: it can operate as a voltage-mode pre-emphasis circuit when connected to the voltage-mode driver, and as a current-mode pre-emphasis circuit when connected to the current-mode driver. This multi-functionality eliminates the need for separate pre-emphasis circuits for each transmission mode, reducing overall device complexity while maintaining improved transmission performance.
Data Source
AI summary
A hybrid transmitter includes a current-mode driver, a voltage-mode driver and an auxiliary driver. The current-mode driver is configured to perform a current transmission. The voltage-mode driver is configured to perform a voltage transmission. The auxiliary driver, coupled to the current-mode driver and the voltage-mode driver, is configured to cooperate with the current-mode driver to enhance a driving capability of the current transmission and cooperate with the voltage-mode driver to enhance a driving capability of the voltage transmission.