Hey guys,

So, I'm converting one of my old projects to instead of using non rechargables, to use LiPo batteries. To save space, I'm only using a single cell, and don't have room for a pre baked solution to handle the battery.

It needs to be able to use the unit, while charging. For that, I followed the guidance found here, using the MCP73831.

For this project, I have to power a LCD display, which uses a nominal voltage of 5v, so I have to boost the voltage. For that, I used a the LiPower unit as a guide, found here. That uses the TPS61200 for the controller.

I have never designed a LiPo charging unit, let alone one that has to boost the voltage. If you could take a look at my schematic and make sure nothing is messed up I would really appreciate it.

One thing I think could be an issue is that I feed both the lower LiPo battery voltage into the booster, and the already 5v from the USB. Will that be an issue? I assume it won't since the booster will keep it at 5v

I am using "CR-AA" as the LiPo (Will change to proper symbol when finished)


I try not to ask such a broad question, but i'm nervous about this, since there's a lot to go wrong when using a LiPo..

Thanks so much!

 

OK, modified the schematic to make the 5V from the USB, if plugged in, bypasses the entire booster now:

 

OK, modified the schematic to make the 5V from the USB, if plugged in, bypasses the entire booster now:

Did this modified circuit work OK? I have used the arrangement as in your original post and it works well.

Have you produced a pcb for the unit?

 

Did this modified circuit work OK? I have used the arrangement as in your original post and it works well.

Have you produced a pcb for the unit?

Yep, I made a PCB for it, and it worked nicely