Hi, I'm new here so please forgive me if I don't know the dos and don'ts just yet.
I'd like to put 12 high power (1000mA) SMD LEDs on a board in a 3x4 array, to occupy as little space as possible. My first experiments with SMD soldering have gone well, so I think the SMD aspect per se will be OK. What I'm concerned about is that these devices kick out a lot of heat in a package roughly 4x4mm. Although my duty cycle will be low (1 second on, >10 seconds off), I still believe I'm going to have to heatsink the LEDs. Manufacturers typically offer a version with a sink, but they are bulky - if I put 12 together, the overall device will be too large.
The way I plan to try is to i) make a PCB on 35 micron prototyping board to accommodate the LEDs, ii) drill through the board where the centres of the LEDs will be, iii) solder the LEDs in place, iv) back fill the holes with thermally conductive / heatsink compound, so I have a 35micron layer behind/under each LED and then finally v) glue that assembly onto a sheet of aluminium to act as the heat sink. It feels like it's going to be hard backfilling the holes in such a way that I don't get greasy heatsink compound everywhere and ruin my chances of a good mechanical bond to the aluminium as well as a good thermal connection.
Here's the data sheet of a typical LED I plan to use, and Farnell's listing of the 35micron board:
http://www.farnell.com/datasheets/1796056.pdf
http://uk.farnell.com/cif/abc16/board-fr4-2-sides-4-10-35µ-100x160mm/dp/1643090
If anyone has any experience of such a project or thoughts on where my plan might fall down or be improved, I'd be very glad to hear!
Thanks,
Andrew.
I'd like to put 12 high power (1000mA) SMD LEDs on a board in a 3x4 array, to occupy as little space as possible. My first experiments with SMD soldering have gone well, so I think the SMD aspect per se will be OK. What I'm concerned about is that these devices kick out a lot of heat in a package roughly 4x4mm. Although my duty cycle will be low (1 second on, >10 seconds off), I still believe I'm going to have to heatsink the LEDs. Manufacturers typically offer a version with a sink, but they are bulky - if I put 12 together, the overall device will be too large.
The way I plan to try is to i) make a PCB on 35 micron prototyping board to accommodate the LEDs, ii) drill through the board where the centres of the LEDs will be, iii) solder the LEDs in place, iv) back fill the holes with thermally conductive / heatsink compound, so I have a 35micron layer behind/under each LED and then finally v) glue that assembly onto a sheet of aluminium to act as the heat sink. It feels like it's going to be hard backfilling the holes in such a way that I don't get greasy heatsink compound everywhere and ruin my chances of a good mechanical bond to the aluminium as well as a good thermal connection.
Here's the data sheet of a typical LED I plan to use, and Farnell's listing of the 35micron board:
http://www.farnell.com/datasheets/1796056.pdf
http://uk.farnell.com/cif/abc16/board-fr4-2-sides-4-10-35µ-100x160mm/dp/1643090
If anyone has any experience of such a project or thoughts on where my plan might fall down or be improved, I'd be very glad to hear!
Thanks,
Andrew.