# Constant Current Output driver connected to 2 COB LEDs - is the hookup valid?

I have a lamp with this hookup. Can someone confirm whether the electrical specs match up such that these can be connected in this way. ld009d-cu03036-m9 - MagTech Constant Current 24-36v output driver AC Input: 120Vac 0.15A 60Hz DC Output: 300mA,24-36V (7% current tolerance) Rated Max Power: 9W -- Weird - seems like this power supply isn't sold anymore, and when I calculate 36*.300 I get 10.8W which makes me scratch my head. The others on the page calculate to about 9W as the series supposedly supports. Here's a page listing the others of the same style: http://www.esop-power.com/products_detail/productId=196.html

These are the COB LEDs, two connected in parallel: http://www.edison-opto.com/get.php?f=Edison+Opto_EdiPower®+V+2PHM03xWxxP32020_Eng_V1.pdf&s=Edison+Opto_EdiPower®+V+2PHM03xWxxP32020_Eng_V1.pdf&path=doc

I'm struggling to figure out whether the electrical hookup is causing the LEDs to blink sometimes at power on. I have two lamps that have the same issue - and one of them has now burnt out one of the COB LEDs.

• If you can cool the LED case to 60'C=Tc or 85'C=Tj then you can regulate the max current this way. – Tony Stewart EE75 May 1 '19 at 15:08
• @SunnyskyguyEE75 No. These CoBs have a 5 V spread @ 85° C. There is no way to get these CoBs to work in parallel with a constant current source without a balancing circuit (e.g. LM3466). I would recommend using a constant voltage source, measuring the Vf, and using a resistor matched to the Vf of each CoB. Use a supply voltage that is fairly close to the Vf (e.g. 38 V) if efficiency is of any consequence. I like the Mean Well adjustable LRS series supplies. meanwell.com/Upload/PDF/LRS-150/LRS-150-SPEC.PDF – Misunderstood May 8 '19 at 2:56
• Yes this would be optimal solution – Tony Stewart EE75 May 8 '19 at 14:01