Here’s Xilinx app note on using CPLDs to perform the same functionality as those common LED driver chips.
Light-Emitting Diodes (LEDs) are commonplace on the modern day Printed Circuit Board (PCB). Whether they are indicating status, activity or some other function, they need to be driven by a device that can provide sufficient current to illuminate them. Traditionally, LED driver devices have been used for this purpose, but this application note aims to demonstrate how that functionality can be incorporated into Xilinx CPLDs to save both cost and valuable board space.