How to split battery voltage and adaptor voltage?

[hdhdhd1]

Hello everyone,

I have a PCB design that is powered by mains electricity via an 9V adapter. When there is no electricity, I want it to switch to li-ion battery mode and provide energy. When there is electricity, the battery must not provide energy. At the same time, I want the battery to be charged from the circuit when not in use.
The battery will be embedded, it cannot be taken out and charged. How to split battery voltage and adaptor voltage?
I didn't know how to do this.
If you have any information, I would like your help.

Thanks in advance.

[pert]

I moved your topic to an appropriate forum category @hdhdhd1.

In the future, please take some time to pick the forum category that best suits the subject of your topic. There is an "About the _____ category" topic at the top of each category that explains its purpose.

This is an important part of responsible forum usage, as explained in the "How to get the best out of this forum" guide. The guide contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

[DrDiettrich]

@hdhdhd1

I didn't know how to do this.

You need a li-ion battery charger module that also allows to draw current from the battery when it is not loading.

[jim-p]

What is the battery voltage?

[6v6gt]

It sounds like you want something like this: https://www.aliexpress.us/item/1005002723862362.html

Maybe also look here: At last -18650 charge/boost module with load sharing?

[hdhdhd1]

I may not have explained it fully. I added the flowchart of the system. hope you understand from there.

I can say that it works like computers power system.
That is, if the system is working with the adapter, there must be no voltage coming from the battery to the system.
If there is no mains electiricity, the battery must be activated and the system must be operated.
The battery should only be activated automatically when there is no mains electricity.

[hdhdhd1]

2S 7.4V Li-ion battery

[hdhdhd1]

thanks

[jim-p]

@hdhdhd1

2S 7.4V Li-ion battery

Do you know if it has built in protection and charge balancing?

[DrDiettrich]

Default operation is from battery. If mains is plugged in then the battery is disconnected and can be loaded if necessary.

[ShermanP]

Isn't this just the standard load sharing (power path) circuit? In the schematic below, you would have 9V from mains instead of 12V. That's assuming the TP5100 will charge 2S cells from 9V.

Note that the AC adapter must be able to supply enough current to power the load and charge the battery at the same time. Also, if you need a manual on/off switch for the device, it should go just before the regulator. That way, the battery can still be charged while the device is switched off.