Hello Everyone,
I am newbie to electronics and this is my first post. Please forgive me if I have posted it in incorrect forum
I am working on a project planning to implement USB-C in my project which will eventually be product someday. There will be USB-C slot on the product which will power the product and charge the lithium ion battery.
Here are basic parameters of the project:
Input parameter:5v,500mA : Considering worst case were user can use any adapter maybe a mobile charger
5v, 1A-3A or 9V-3A, or 12V-2.25A, 20V-1.35A Considering USB-C PD options available.
Battery specification:1s3p battery pack
3.7V, 2550mAH
14550 cells
Datasheet :
http://www.tenergy.com/30001_datasheet.pdfOutput requirement:12V, 0.7A maximum requirement.
I have attached rough block diagram for the same.
Block diagram explanation :Planning to use USB-C CC controller IC which will handshake information on higher current requirement in case adapter is capable. There is charge controller IC (
https://www.ti.com/lit/ds/symlink/bq25703a.pdf) which is Buck-Boost Charge Controller With System from Texas instrument which can support input and output requirement of project.
Charge controller IC is connected to battery for charging. Further the battery provides output to boost converter (3.7V->12V) as final output.
As per my understanding : Batteries can be charged at
0.2C nominal : which is 0.5A (
Will it take roughly 5hrs to charge?)
0.5C : 1.275A
1C : 2.55A charging current (
Will it take roughly 2.5hrs to charge?)
Battery can discharge :
3.7V and
0.5C - 1.275A current
1C - 2.55A current
3C - 7.65A current (
Are the current mentioned correct?)
Questions: 1. If I connect a boost converter which will provide 12V and rated at 0.7A at output what should be input current of boost converter IC?
I followed this document of TI instrument (
https://www.ti.com/lit/an/slva372c/slva372c.pdf) (90% efficiency, 30% p-p ripple current)
the input current required comes out to be 2.62A. Is this correct?
2. Am I missing anything in this circuit?
3. Can 5V, 500mA mobile charger charge the batteries? What will be charge time?
4. For above mentioned battery pack, can it power 12V, 1A product without any issue?
What will be discharge time?
5. If there is USB PD adapter at input, can it provide power to system with boost converter in between?
6. Should I consider 3S combination of lithium ion batteries instead of 1s3p with boost converter at input? Will it be more efficient system?
Thank you very much in advance
