Can someone help me with designing a schema to regulate voltage to dim an LED light? I have 3 LEDs connected in parallel. One LED has following specification:
Forward voltage = 2.75 V (max. 3.4 V)
Forward current = 1000 mA
Power consumption = 3.4 W
Reverse voltage = 1 V
So, if I understand it correctly, I need output of 2.75 – 3.4 V and 3 Amps to power them.
My goal is to regulated voltage to these LEDs to be from 2 V to 3.4 V (or 0 V to 3.4V if not possible to limit the low voltage) and constand current of 3A. I also prefer the schema to consist only of necessary components and to make it as small as possible to fit it in the flashlight housing. I read about source voltage to be as close to the output voltage to minimize the heat dissipating. My 18650 battery, fully charged, gives me about 4.1V (I understand that the battery has to be capable of delivering 3A – in case I can connect more in parallel too), but some of my voltage regulators I have at home just won't provide as much as required 3.4 V. Then I read about low dropout voltage regulators (LDO) and did some research too, but have none at home to try it. I thought that you electrician geeks would probably help me out instead of me trying by errors to figure this out. Also, I have few 10K or 1K potentiometers laying around that looks like this, but I am afraid that they may not be suitable for my purpose, perhaps because of the high 3A current I need? Perhaps, it can be designed, so it could be used? It perfectly fits hole of my flashlight housing. Can you please provide schema, either for voltage regulator with some LDO or voltage divider schema, please?
I looked this forum for similar posts, but it doesn't answer all my questions, e.g. if my potentiometer will work or not as it is not heavy-duty.
Your help is very appreciated and that you in advance for your eventual help.
PS: Of course I have only some basic knowledge about this, so please bear with me. Thank you.
Best Answer
The simplest would be a MOSFET as a buffer plus your pot.
Fancier ones would use the pot to adjust thee regulators output to thee led, voltage or current.
Without knowing what you have, tough to be more specific.