[SOLVED] LD-A4 external OTP question

tekwyzrd · 2019-11-23T16:38:53.000Z

I’ve been searching for info on just how the sense resistor for the LD-A4 should be connected and mounted. Could someone who has done it provide details?

led4power · 2019-11-23T17:30:19.000Z

You need to solder NTC on MCPCB, on 16mm there is only one place, on 20mm PCBs, NTC goes to left footprint:

To connect NTC to driver you need only one wire, which connects "T" pad on 16mm PCB / "T1" pad on 20mm PCB, and "T" pad on driver, which is small through hole pad at ~4 o'clock on LD-x4 drivers.

tekwyzrd · 2019-11-23T18:28:30.000Z

So, the external otc ONLY works with YOUR emitter boards? It seems to me that info should be included in the manual and listing.

led4power · 2019-11-23T18:38:07.000Z

You don't have to use my PCBs, but I'm not aware of other MCPCBs with place for NTC. In theory you can carefully glue NTC with arctic alumina adhesive or similar stuff to MCPCB and solder wires directly on NTC (in that case other NTC pad should be connected to batt+ which is available on MCPCB because LED anode is connected to it.

tekwyzrd · 2019-11-23T19:03:28.000Z

Thanks for the info. I’ll mark this solved.