Maker Pro
Maker Pro

High power LED power/driver question.

KarelSoel

Aug 18, 2021
1
Joined
Aug 18, 2021
Messages
1
I have 8 high power "3Watt" LEDs setup in series. They Are 3.2-3.8V, 700mA. If I did the math correctly. I have to get a power supply that is 30.4V @ 700mA. Is this correct? Also, I'm Confused as to weather or not I need a driver. I've google searched it, but I'm still slightly confused as to the purpose of a driver. Anyone know where I can get a power supply with this rating?

Any help is appreciated.

Thanks
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
12,713
Joined
Nov 17, 2011
Messages
12,713
I have to get a power supply that is 30.4V @ 700mA.
At least.
I'm Confused as to weather or not I need a driver
I'm still slightly confused as to the purpose of a driver.
You'll need some form of current limiting. Otherwise the LED current is not controlled and can lead to thermal runaway, burning your LEDs.
Either a series resistor or a constant current LED driver. Both will require a higher input voltage than computed above.
Example: Using a 2.2 Ω / 2 W resistor the voltage drop will be dV = 2.2 Ω ×0.7 A = 1.54 V, therefore the output of the power supply needs to be 30.4 V + 1.54 V = 32 V.
 
Top