Non inverting DC-DC converter that makes fix 4V from a decreasing voltage from 4,2V to 2,8V?

Thread Starter

Tamás Fegyvári

Joined Sep 26, 2017

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.


Joined Mar 30, 2015
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).


Joined Oct 7, 2019
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: