Hi!

Is it possible to make a a non inverting DC-DC converter that makes a fix 4V from a Li-ion battery's voltage. I need about 1,5A.
The input voltage starts from 4,2V and decreasing to 2,8V as the battery discharging.

 

What is the battery amp hour capacity?

 

What is the battery amp hour capacity?

It's all in the planning phase. It will be around 2500mAh.
The load doesn't need a constant 1,5A. It will be around 200mA average with 1,5A peak.

 

It's all in the planning phase. It will be around 2500mAh.
The load doesn't need a constant 1,5A. It will be around 200mA average with 1,5A peak.

You're going to need to be more specific before anyone can offer any reasonable advice.

One thing to be aware of is that power in to your regulator must be greater than power out (no regulator is 100% efficient). When your battery is at 2.8V, it won't last long if you expect it to provide 1.5A at 4V (6 watts).

 

Look at this option. It just makes the 1.5A. Input range is large. I think you should shut it off if the battery voltage is too low. There are other parts with a built in shutoff when the battery is done.

Another slightly larger option:

 

Look at this option. It just makes the 1.5A. Input range is large. I think you should shut it off if the battery voltage is too low. There are other parts with a built in shutoff when the battery is done.
View attachment 200056
Another slightly larger option:
View attachment 200057

Thank you!
Unfortunately I didn't find any of these ICs that i could solder with hand.