Why the COB (Chip On Board) LED’s Forward Current vs Forward Voltage characteristic, shows 30V+ at 1A?

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I have an LED project using 100 Citizen CLU048-1212C4 LEDs.

I need to run each LED at 70W, and I want to run every 5 LEDs on 1 power supply.

I was thinking of using the MEAN WELL LSR-350-35 (it takes a long time to show PDF)

Video review of the power supply.

This screenshot is from the LED datasheet

I saw in the power supply datasheet:

INPUT Voltage Range : 90 ~ 132VAC / 180 ~ 264VAC by switch 240 ~ 370VDC (switch on 230VAC)

This screenshot is from the power supply datasheet

Where I live, the electrical power 220V and 50Hz.

I think if I connect LEDs parallel it’ll be good the current of the power supply (9.7A) will be divided on LEDs count so every LED will take 9.7A/5 = 1.94A for each LED DC voltage 36V I think that means 1.94*36=69.84W ~ 70W (automatically.)

• Is that power supply good for this project?

I feel confused from this screenshot from the LED datasheet. I think I need to drive the LEDs at ~38V to reach 1.9A, I’m not sure about that.

This screenshot is from the from the LED datasheet

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1 Answer

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1. About COB LEDs’ V-I Characteristics

Well you LED module is COB (Chip On Board), which means the many LEDs are serially squeezed within one module. You might like to read this tutorial The Basics of Chip on Board (COB) LEDs – Rich Miron, Digi-Key Electronics 2016aug03 for more details.

Usually one LED taking 1A has a voltage of approx 3V. So your module has approx 36V at 1A, implies there are 12 LEDs in series inside the module.

2. About COB LED’s input voltage

You might like to read my answer to the following Q&A:

What’s the voltage used to power LEDs inside an LED light bulb? Asked 2 months ago Active 2 months ago Viewed 170 times

My answer explains that special AC mains to DC conversion uses the “Capacitive Dropper” accepts AC input in a range of 185 to 150VAC, like many smart phone chargers accepting 110VAC or 230VAC.ShareCiteEditDeleteFlagedited 1 hour agoanswered 2 hours agotlfong011,73611 gold badge66 silver badges1212 bronze badgesAdd a comment