Hi,
Somewhere in my project, I've to drive a power LED. My operating voltage is 9V to 16V & I've to limit the current flowing into LED to 500mA. Initially thought of using a series resistor but the wattage is coming so high. Could anyone pleasehelp me in designing simple, efficient & cost effective circuit.
Better use the following circuit
The constant current source has a drop voltage of 3 V, so the supply voltage should always be 3 V higher than the LED voltage and can be up to 37V which is the maximum input voltage of the LM317.
See datasheet to calculate resistance also you must read this