5vdc to 3.8vdc step down

[StealthRT]

Hey all i am in need of some help with stepping down a 5vdc to 3.8vdc so that i can power my phone.

The battery that's powering the phone is rated at 3.8vdc 1730mAh 6.57Whr.

What all would i need in order to step down from the 5vdc to around the 3.8vdc mark?

The USB 5vdc is rated at 5.1vdc 2.1A.

Any help would be great!

 

[ronv]

Are you trying to charge the battery or replace it with a power supply?

 

[Diver300]

Telit has some good guidelines on powering their phone modules. A conventional phone has basically the same requirement.

https://www.telit.com/en/products/gsm-gprs.php?p_id=12&p_ac=show&p=47 and go to Telit_GE865-QUAD_Hardware_User_Guide_r15, page 31

You should note that mobile phones take current peaks up to 2 A, and are very difficult to provide a supply for.

I can't find the thread, but someone here had problems running a phone from a 3 A power supply, possibly because of the length of the wires that were used.

 

[StealthRT]

Trying to just power it, not charge it.

 

[ronv]

Try something like this. Make sure to follow the datasheet and build it inside the phone if you can.

https://www.electro-tech-online.com/custompdfs/2013/03/1528fb.pdf