Triode
Well-Known Member
**broken link removed**to the page on the LED I'm talking about. I've ordered one, along with a copper sinkpad. I plan to mount it on a large CPU heatsink and put it in a projector. I've already modded the projector to not detect that it's mercury lamp is missing. I think I have the idea, but since it's a $17 component, and I need to reflow mount it, I want to be as sure as possible that I don't toast it.
here's a snippet of the specification:
Maximum Drive Current 4.8 A (6 V) 2.4 A (12 V)
Maximum Power 32 W
Light Output 4022 lm @ 32 W
I see a few options for driving this. There are very inexpensive current controlled power supplies on Ebay which say they are meant for LEDs, but I don't know how much I trust them. I do have access to a programmable load, so I could certainly get a $10 30W "LED driver" from china and see if it's ok, that would be a long wait though.
Here's the plan I would like a second set of eyes on to tell me if there is a problem:
I'm considering this basic current limiting circuit, set to 2.4A with a 19V 10A laptop power supply:
Because I have them on hand I'm thinking of using:
26K4623 for Q1
(NPN, 300V, 50MHz,
https://www.newark.com/on-semiconductor/mpsa42rlrmg/high-voltage-transistor-npn-300v/dp/26K4623
NR4941 for Q2
(50V, 30A, 75W)
https://www.digikey.com/product-detail/en/BUZ11_NR4941/BUZ11_NR4941-ND/1954150
Does this sound like a good way to do it?
By the way, am I correct in assuming that under voltage would probably not damage this device? I plan to run it in the 12V configuration but when testing my circuit I might connect it to a variable power supply and slowly bring up the voltage while monitoring the heat on the mosfet and LED, and the current across the LED. If I understand correctly, until there is enough voltage to reach this circuits target current, it will run full on.
If I just connected the LED to a 12V power supply would it probably run fine anyway? Is this kind of circuit absolutely essential, or more of an extra precaution?
here's a snippet of the specification:
Maximum Drive Current 4.8 A (6 V) 2.4 A (12 V)
Maximum Power 32 W
Light Output 4022 lm @ 32 W
I see a few options for driving this. There are very inexpensive current controlled power supplies on Ebay which say they are meant for LEDs, but I don't know how much I trust them. I do have access to a programmable load, so I could certainly get a $10 30W "LED driver" from china and see if it's ok, that would be a long wait though.
Here's the plan I would like a second set of eyes on to tell me if there is a problem:
I'm considering this basic current limiting circuit, set to 2.4A with a 19V 10A laptop power supply:
Because I have them on hand I'm thinking of using:
26K4623 for Q1
(NPN, 300V, 50MHz,
https://www.newark.com/on-semiconductor/mpsa42rlrmg/high-voltage-transistor-npn-300v/dp/26K4623
NR4941 for Q2
(50V, 30A, 75W)
https://www.digikey.com/product-detail/en/BUZ11_NR4941/BUZ11_NR4941-ND/1954150
Does this sound like a good way to do it?
By the way, am I correct in assuming that under voltage would probably not damage this device? I plan to run it in the 12V configuration but when testing my circuit I might connect it to a variable power supply and slowly bring up the voltage while monitoring the heat on the mosfet and LED, and the current across the LED. If I understand correctly, until there is enough voltage to reach this circuits target current, it will run full on.
If I just connected the LED to a 12V power supply would it probably run fine anyway? Is this kind of circuit absolutely essential, or more of an extra precaution?