Methods and devices for matching transmission line characteristics using stacked metal oxide semiconductor MOS transistors. Apparatus and methods provide low voltage differential signaling LVDS driver with replica circuit biasing and protection for hot plugging. The circuit of FIG. The feature should also be able to recover to normal behavior after the fault has disappeared. The gates of these protection switches , can be coupled to control signal outputs of the protection control circuit such that protection switch is closed and protection switch is open for a normal mode of operation and protection switch is open and protection switch is closed for a protected mode of operation.

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The output impedance can be centered on Z eq and a particular desired output impedance can be achieved by proper sizing of the transistorsas explained earlier in connection with Equation 1. Such a fault detection feature should be able to selfterminating excessive current then shut off excessive current flow.

Also, for proper operation of differential signaling at high speed, these drivers should be terminated into an appropriate channel characteristic impedance.

US7898295B1 – Hot-pluggable differential signaling driver – Google Patents

The apparatus of claim 9wherein the pullup resistors are active at least when a fault corresponding to a short to ground is detected, wherein the protection control circuit further comprises pulldown resistors coupled to each line of the differential output, wherein the pulldown resistors are active at least when a short to V DD has been detected, wherein the pulldown resistors permit reset of the protection control circuit.

Since for many applications a full function network is not required throughout the video architecture and for some compounds, data compression is not feasible due to image quality loss and additional latency, bus oriented video transmission technologies are currently only partially attractive. Views Read Edit View history. For example, under normal conditions, protection switchesare biased ON switch closedand switchesare biased OFF switch open.


Field of the Invention The invention generally relates to electronics. The apparatus of claim 2wherein each of the steering switches is an NMOS transistor.

USB1 – Hot-pluggable differential signaling driver – Google Patents

Preferably, LVDS drivers are hot-pluggable. The illustrated configuration avoids such strongly coupled feedback loops, especially in the signal path. It is compatible with almost all data encoding and clock embedding techniques.

Fixed termination scheme for differential receiver that compensates for process, voltage, and temperature variations. The usage of the source follower configuration does not waste power in the termination devices FIG. In addition to the foregoing, an LVDS driver should also have a fault detection feature to handle accidental shorts of the output pads to an external high or low supply rail.

In a typical implementation, the low-volage injects a constant current of 3. The invention generally relates to electronics.

Low-voltage differential signaling

Although particular low-voltwge are described herein, other embodiments of the invention, including embodiments that do not provide all of the benefits and features set forth herein, will be apparent to those of ordinary skill in the art. Double termination is necessary because it is possible to have one or more transmitters in the center of the bus driving signals toward receivers in both directions.

To serve this application, FPD-Link chipsets continued to increase the data-rate and the number of parallel LVDS channels to meet the internal TV requirement for transferring video data from the main video processor to the display-panel’s timing controller.

MLVDS has two types of receivers.

Low-voltage differential signaling – Wikipedia

This level of output impedance variation is acceptable for LVDS applications. In one embodiment, N is in a range of about 5 to about This scaling N by greater than 1 decreases the current passing through the resistor relative to the resistor FIG.


As previously noted, the power-off leakage current should be relatively small. LVDS is a physical layer specification only; many data communication standards and applications use it and add a data link layer as defined in the OSI model on top of it.

This can be achieved through proper sizing of the output source follower such that the relationship expressed low-volgage Equation 1 holds.

It uses termination resistors at each end of the differential transmission line to maintain the signal integrity. Other values for N will be readily determined by one of ordinary skill in the art. When a single differential pair of serial data is not fast enough there are techniques for grouping serial data channels in parallel and adding a parallel clock channel for synchronization. Although described with reference to these specific embodiments, the descriptions are intended to be illustrative and are not ckos to be limiting.

Unsourced material may be challenged and removed. Camera Link standardizes video interfaces for scientific and industrial products including cameras, cables, and frame grabbers. Outpuf illustrated protection control circuit has a fault detector and a wake-up or reset circuit In serial low-voltagw, multiple single-ended signals are serialized into a single differential pair with a data rate equal to that of all the combined single-ended channels.

The apparatus of claim 1wherein the explicit resistor is integrated into an integrated circuit.