Laptop AC Adapter Powering DC-DC Boost Converter, Why Can't I Get The Power I Need Out Of The Boost Converter?

Question

I am using a 15v 3amp laptop AC adapter to power a 400W DC-DC boost converter.

The converter is powering a high power LED lamp with a Vf of 42 and current limit of 2.5amps.

However, I can only get the converter to go up tp 38v and around 1.6amps. After it reaches that point it shuts off and resets itself.

Why doesn't the converter boost the voltage to where I need it?

Is it The AC adapter not able to supply enough power?

I thought that was the whole point of the boost converter, to boost the voltage. I dont understand what factors limit the boosted output

Answer 1

The longer detailed answer (Ash) misunderstands what you are doing and dmb.. answer is perfectly correct without the numbers.

You don't understand wattage vs voltage and are trying to use a 45W power supply to give you up to 105 watts for the lamp which is like asking why the 4 cylinder Fusion engine I put in my dump truck won't move the load of 10 tonnes of gravel.

Answer 2

"I thought that was the whole point of the boost converter, to boost the voltage."



That's correct, and it is "boosting" the voltage.



"I dont understand what factors limit the boosted output."



You can't "boost" the power. The output power of any converter/booster will always be a less than the power in. There are always unavoidable losses in the process.

Answer 3

Power you need = 42V x 2.5A = 105W



Rated power you have from laptop AC adapter = 15V x 3A = 45W



Max Power you are getting out of laptop AC adapter = 38V x 1.6A = 61W



You are supposed to use this laptop AC adapter to provide only upto 45W of power. However you are already loading it over its allowed rated capacity by using power upto 60W. Either the laptop adapter is resetting due to overload or the booster is resetting due to low power.



Even if you use 2 of these laptop adapters in parallel you are rated for just 90W. Although you can pull in required105W, you will be overloading the adapter. They can overheat and burnout over time.



What you need is a DC powersupply that can provide at least upto 130W power