High power LED Ledengin 10W. How can I drive 4+1 of these from a laptop power supply? Answered
Dear fellow hobbyists,
I have four deep red, 10 watts Ledengin bulbs mounted on a MCPCB (as well as one cool white 10 watts bulb from the same company). I would like to bring them to life using a laptop power supply. I know that I do absolutely need a constant current to avoid getting SEDs or friods. Unfortunately my knowledge of circuits is very basic and several decades old. I have read and re-read several times the excellent instructubles tutorials and gathered more information from the web. I think I got it (wellÃ¢â¬Â¦sort of) and I have successful built a small array of inexpensive, low power (20 mA) LEDs, using a resistor as the current limiting device. However I am aware that this is a rather inefficient way to feed high power LEDs, particularly related to power dissipation (i.e. efficiency of the circuit). I would like to build a LED driver using either 1) the NFET + NPN circuit #2 from Dan (https://www.instructables.com/id/Circuits-for-using-High-Power-LED_s/) but I am not sure if the listed components are good enough to drive four/five 10W LEDs (mid power LEDs are used in the example), or 2) find a buck pack that does not cost a fortune and is guaranteed to work (National semiconductors seems to have a few at very low prices, such as Ã¢â¬Â¦., but I am not sure they will do the job and how well) . Also, I would like to know if it is possible to drive the 4 red together with the 1 white LED from the same power supply, or if it is better to use two PS, each with its own driver? The two ledengin LEDs are LZ4-00R210 for the red and LZ4-00CW10 for the white bulb. I intend to drive them at 700 mA to maximize shelf life and the maximum Vf for this current are 13.76 V for the red (only one bin code) and 16.64 V for the white (for safety I was advised to use the highest Vf bin value from the datasheet as it is close to impossible to get the correct bin code specific for the bulb from the distributor). I am actually considering running the 4 red + 1 cool white LEDs all in parallel, with each individual LED having its own current limiting device (the inexpensive ones from Dan): a bit more involved but maybe the safest?
Thank you in advance for all the help you can give me.