FPD-Link

Flat Panel Display Link (FPD-Link) is the original high-speed digital video interface created in 1996 by National Semiconductor (now within Texas Instruments). It is a free and open standard for connecting the output from a graphics processing unit in a laptop, tablet computer, flat panel display, or LCD television to the display panel's timing controller. Most laptops, tablet computers, flat-panel monitors, and TVs use this interface internally. Laptops designed before 1996 and devices with smaller display resolutions often use a TTL or CMOS interface instead.

FPD-Link was the first large-scale application of the low voltage differential signaling (LVDS) standard. National Semiconductor immediately provided interoperability specifications for the FPD-Link technology in order to promote it as a free and open standard, and thus other IC suppliers were able to copy it. FlatLink by TI was the first interoperable version of FPD-Link.

By the end of the twentieth century, the major notebook computer manufacturers created the Standard Panels Working Group (SPWG) and made FPD-Link / FlatLink the standard for transferring graphics and video through the notebook's hinge. Since it was the first successful use of LVDS, to this day many display engineers use the generic term LVDS when referring specifically to FPD-Link / FlatLink product technology.

There have been numerous attempts to displace FPD-Link as the standard internal video interface in mobile devices and LCD TVs. For example, VESA designed Embedded and Internal DisplayPort with the intention to replace FPD-Link as an internal interface. Embedded DisplayPort has seen some success in notebook computers, but Internal DisplayPort has limited use inside LCD TVs. The reason for FPD-Link's resilience is its simplicity and the low cost of implementation.

FPD-Link became successful at transmitting 18-bit RGB raw video because it reduced the cable size and improved the electromagnetic compatibility by using LVDS. It uses LVDS to transmit the video data on three twisted pair, and another pair to transmit the LVDS clock signal. These four differential pairs are carrying the same information previously transferred over 22 wires, which is almost a 65% wire reduction. In addition, the close coupling of the twisted pair wires improves the EMC because the equal and opposite LVDS currents in the wires create equal and opposite electromagnetic fields that tend to cancel each other's effects. This reduces the radiated emissions. The reduced vulnerability to electrical noise interference comes from the fact the noise affects both signals commonly. Since the LVDS receiver senses the difference between the two commonly affected signals, it senses no impact from the common mode noise.

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