Configurable Differential Driver for Shared LVDS and TMDS I/O

Solution Overview

Problem

Providing both Low Voltage Differential Signaling (LVDS) and Transition Minimized Differential Signaling (TMDS) drivers on a single communication device or circuit increases the differential Input/Output (I/O) area and cost due to structural differences and varying operating parameters.

Innovation Solution

A combination differential driver with a logic control and multiplexer is used to selectively configure the driver as either an LVDS or TMDS driver, employing dual bias transistors and a configurable bias circuit to adapt to different operating conditions, reducing the need for separate drivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If both LVDS and TMDS drivers are provided on a single communication device, then the device can support multiple signaling standards, but the differential I/O area and cost significantly increase

Engineering Contradiction:

Improvesupport for multiple signaling standardsVSAvoiddifferential I/O area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent implements a universal differential driver that can operate in both LVDS and TMDS modes by using a shared driver core with configurable biasing circuits. The driver accepts a mode selection signal that reconfigures the biasing network to match the required signaling standard, allowing one physical driver to perform the functions of what would traditionally require two separate drivers, thereby reducing the differential I/O area while maintaining support for multiple signaling standards

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs dynamic reconfiguration of the driver circuit through mode selection signals that adjust biasing conditions in real-time. The driver can switch between LVDS and TMDS operating modes by changing the biasing state of transistors and current sources, enabling the same hardware to adapt its electrical characteristics to match different signaling requirements without requiring separate static circuits for each mode

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If both LVDS and TMDS drivers are provided on a single communication device, then the device can support multiple signaling standards, but the manufacturing cost increases

Engineering Contradiction:

Improvesupport for multiple signaling standardsVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent implements a universal differential driver that can operate in both LVDS and TMDS modes by using a shared driver core with configurable biasing circuits. The driver accepts a mode selection signal that reconfigures the biasing network to match the required signaling standard, allowing one physical driver to perform the functions of what would traditionally require two separate drivers, thereby reducing the differential I/O area while maintaining support for multiple signaling standards

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functionality of separate LVDS and TMDS drivers into a single integrated circuit by combining their common components (differential pair, current sources, output buffers) into a shared driver core. The mode-specific elements (biasing networks) are also integrated and reconfigured based on the operating mode, reducing the total component count and manufacturing complexity compared to providing two independent driver circuits

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7656198B1Method and apparatus for providing a combination differential driver

Publication Date: 2010.02.02 XILINX INC

AI summary

In one embodiment, an integrated device is disclosed. For example, in one embodiment of the present invention, a device comprises a logic control, and a combination differential driver coupled to the logic control, wherein the logic control receives a control signal for configuring the combination differential driver as a Low Voltage Differential Signaling (LVDS) driver or as a Transition Minimized Differential Signaling (TMDS) driver.