Electronic – Cannot properly power LEDs

ledpower

I have two boards from the led headlights. Struggling to power it, I burnt one and now trying to understand how to properly power it.
Circuit itself looks quite straightforward: two upper LEDs are connected in series and connected to the pins 1 and 2. And bottom LED is connected to the pins 5 and 6. However I failed to turn them on.

enter image description here

I was trying to use different resistors in series with the LED but with no luck.
Eventually I connected it without resistor to voltage regulator and started to gradually increase the voltage from 2 V and above.

I used an ammeter to monitor the current. With 2 V voltage current was about 150 mA but no light form the led. Also I should mention that the board has a huge heatsink even though LEDs are only 3mm x 1.5mm. So step by step I increased voltage up to 12 V. Current was about 1.8 A (and heatsink was quite warm). But at some point I finished with short circuit inside the LED.

Appreciate any ideas about how to properly power this board

UPD: Also multimeter shows 0.7 V voltage drop on the LED. Is this normal? I thought typical voltage drop for high power LEDs is about 3 V.

UPD2: I replaced burnt LEDs with different ones and they work fine using the same power schema. My guess is that it somehow connected with LEDs themselves. They were 100% good and they are not IR. I don't understand why voltage drop on the LED is only 700 mV when for high power LEDs it's typical to have 3-4 V. So when I set voltage about 2 V (which is higher than 0.7 V) I have current about 200 mA already, but nothing happens. From my understanding it should start glowing event with 10 mA. Am I right?

enter image description here

Best Answer

as you mention these boards are from Headlamps, with LED board did you find another board inside the headlamp?. because the board you are missing is LDM (LED Drive Modules). This is a self-contained power supply, that accommodates the LED’s powers. The modules have multiple channels to provide varying currents to different LED’s. These modules are used to power LED’s which are used to customize to accommodate the LED’s it powers. if you have that board, then you just connect the board with the LDM and give power to the LDM between 9V to 16V as it is headlamp it can take up to 6Amp of current approx, and check the results. if you didn't find the board don't worry, but you can still turn on these LEDs but not recommended. use the power supply in CC mode to drive the LED board.in my case, what I have done, I'll explain in brief, I have APlab 30V10Amp variable power supply, connected the LED board to power supply and I keep the current knob to 0 and start increasing voltage knob to around 6 volts as I increase the voltage PS goes into the CC mode then I started increasing the current the LED start glowing. it worked for me maybe it will work with you. note:- do not run the LED for more than 10 sec. they are high power LED and without proper heat management the led may damage.