Asynchronous Control and Driver for High-Speed LED Display with Local Scanning Approach

This study presents an extendable full-colour light emitting diode (LED) display based on field-programmable gate array implementation. The LED display panel system includes memory management, image format conversion, serial parallel interface (SPI) interface, local scan techniques, LED driver and pulse width modulation (PWM) data control. To reduce I/O ports, data transmission system uses SPI interface to send the PWM data to the LED panels. A novel local scan technique, which could use a lower frequency for data transmission and achieve higher frame rate for LED display, is proposed. Each display module contains local memories for data self-scanning to LED. The display continues even if there is no new data input. The advantages are that the display rate does not care about the speed of data transmission. Only motion area, rather than complete frame, required sending data to display, which can greatly improve data bandwidth. This is very useful for high-resolution display system since even low data rate can achieve the fast display refresh. This approach is a module-based design, which can easily be extended to any size with auto re-configuration without using embedded processor.