It is a product that has been created from scratch in very close corporation
with our customer. The system architecture is fully defined by FPGA
Solutions. Hardware design is done together with one of our partners. Other
tasks, like FPGA design, embedded software and PC software implementation
have been done 'in-house'. The system is in full production. The LED displays
with our control system are installed throughout the world.
LEDs are far from perfect to apply in a display. Brightness and color
reproduction heavily depends on the current, temperature and age.
Furthermore, LEDs need to be binned (selected) to prevent large brightness
deviations. Most LED display control systems don't have any correction
options built-in. FPGA Solutions has developed a modular LED display control
system (for indoor and outdoor displays) with the possibility to connect a
measurement camera system to calibrate the display. The result is perfect
image quality, at least as good as the best High-End displays in the market,
but at a much lower price level.
High-End LED display control system
The system has all the features a professional system should have, like an automatic
brightness control with many options to connect multiple light sensors and a selectable
gamma correction. Multiple PWM LED drivers are supported with a bit depth up to 16 bits.
Drivers with programmable current outputs are fully supported. The FPGA designs are all
protected against cloning, overbuilding and reverse engineering.
The system components are a DVI controller and multiple transceiver boards that are
mounted in the LED cabinets. The DVI controller connects the digital video signal (from a
computer or other video source) and the Gigabit Ethernet wires to the LED cabinets. The
system has double (redundant) wiring so that when a single connection fails the display
continues to operate as it should. The controller continuously monitors the status of the LEDs,
power supply and temperature of each transceiver board.
The heart of the controller is the Xilinx XD3S400AN FPGA. Digital video enters the FPGA via
the DVI receiver TFP401A. This chip converts the serial DVI stream to video and
synchronization signals. In the FPGA the video images are cropped and converted to Ethernet
packets. These packets are send to the transceiver boards inside the LED cabinets along with
the control packets.
The embedded processor inside the FPGA takes care of all communication with the
transceiver boards, internal and external Flash memories, the DNA module and the on-
board temperature sensor. To setup the controller a PC can be connected with a RS232
On the transceiver board the Xilinx XC3S400AN is also the main component. Ethernet data
goes in and out via the dual Gigabit Ethernet PHY and is stored temporary in external
PSRAM memory. Inside the FPGA the intelligent video processing is executed, like gamma
correction and matrix calculations for correcting the LEDs.
The RGB data comes out in a serial format in 8 channels to feed the driver boards. Each
transceiver card is capable of driving 128x128 pixels (each pixel normally has 3 LEDs - Red,
Green and Blue). To support all kinds and brands of LED displays a modular 80 pins
connector is used so that customers can connect to their own custom connectors.
The system, which has been developed for a Dutch customer, gets the most out of professional LED displays for use in
stadiums, events and advertising boards. It is a complete system solution for LED display manufacturers that can be
used to improve the color and brightness uniformity of all kinds of LED displays.