How Do You Drive an eDP Display from an LVDS Controller or SBC?
May 6, 2015
An eDP display can be driven from an LVDS controller or single-board computer through an adapter board that converts dual LVDS into eDP, or replaced at the source with a controller that outputs eDP directly. Which route fits depends on whether the existing electronics are staying in the design. We supply both from Ronkonkoma, New York, along with the panel and cables, and help work out which one a design needs.
What is eDP, and why do newer panels use it?
eDP (embedded DisplayPort) is the internal display interface that panel makers moved to for full HD resolution, starting with mid-size panels of about 11 to 17 inches. Compared with LVDS it needs fewer wires, draws less power, carries higher data rates and gives better EMC performance. The catch for equipment builders is that many graphics cards, SBCs and controller boards in service still have only an LVDS output, so adopting a newer panel can mean bridging the two.
How do you connect an eDP display to a dual-LVDS output?
With the LVDS2eDP adapter board, which converts a dual LVDS signal into a 2-lane eDP signal. It connects dual-lane eDP panels up to WUXGA (1920 x 1200) to Prisma and Artista controller boards, SBCs, industrial PCs or a customer’s own system, and loops power and backlight control through. It is rated -20 to +80°C. One limit to check early: single-lane WXGA (1366 x 768) panels are not supported. The adapter lets a design keep its proven controller while moving to a current panel.
What if the computer has eDP and the panel is LVDS?
The eDP2LVDS adapter covers the reverse case. It connects single or dual LVDS panels up to 1920 x 1200 to a single- or dual-lane eDP output, which is common on newer industrial PCs and SBCs, and also loops power and backlight control through. Its operating range is -25 to +80°C. Both adapters are listed on our interface boards page.
Which controller drives an eDP panel directly?
Today that is the PrismaECO-4K, which takes HDMI 2.0 and DisplayPort 1.2 in and drives 4-lane eDP panels up to 4096 x 2160 at 60 Hz, at -20 to +60°C. It is the alternative our product pages name for the two dedicated full HD eDP controllers, the PrismaECO-eDP and PrismaECO-eDP-II, which are both discontinued. For UHD panels with 8-lane eDP or V-by-One, the Prisma-4K-Advanced is the step up.
The PrismaECO-eDP, launched in 2015, set the pattern for how we configure these boards. Its configuration software handled port selection, timing and EDID programming, and a finished configuration and OSD settings could be read from one board’s EEPROM and copied to others. That is what makes a configured controller practical for series production: the settings are worked out once and repeated on every board. The 12.5-, 14- and 15.6-inch panels we first offered as eDP kits are no longer available, so a new design starts from a current panel.
How do you choose between an adapter and a new controller?
Keep the existing controller and add an adapter when the computer side of the design is qualified and only the panel is changing. Move to an eDP controller when the video source is HDMI or DisplayPort anyway, or when the design is moving to UHD. In both cases the details that decide it are the panel’s lane count and resolution, the supply voltage, and the operating temperature range.
For the full Prisma range, see what a Prisma TFT controller does and which boards are current. Prisma and Artista boards are developed by FORTEC Integrated (formerly Distec), our sister company in Germering, Germany, within the FORTEC Group.
Tell us which panel you want to use and what is driving it, and we will take it from there. We recommend the adapter or controller, configure it to the panel, supply it as a kit with the cables, and stay with the project from first samples to series production, backed by our technical services.
