Battery Charging Circuit

[electronicsLearner77]

I need to design a battery charging circuit, the initial study i have done this is what i need to do

a charging circuit which i have to come up, circuits for voltage and current feedback. Is my initial understanding correct? This is for Li-Ion battery, if it is 5AH, what are the other parameters i need to know, do i need to know the charging current? There are circuits TI charging circuits can i use them? Please help.

 

[Bluejets]

Get it wrong and Li-ion cells will let you know in a spectacular reaction.
Battery University web site will tell you most of what is known about them.
Other than that, why try to re-invent the wheel so-to-speak?
There are literally thousands of chargers out there, smart chargers, built by ones who know what they are doing.
Given the technology included in them, cheap as..........cheaper than you'll ever build one that's for sure.

 

[electronicsLearner77]

It is only a part of the circuit, i also need to add serial communication, sensors etc in the hardware board. So, i am looking for the charging circuit as a first step.

 

[danadak]

Give us a little background :

1) Student exercise ?
2) Your skills, like circuit building experience, prototyping, programming (what languages) ?
3) Basics, like what resistors, capacitors, transistor do and how to use them ?
4) Ever worked with embedded board/microprocessor ?
4) Project timeline ?

Regards, Dana.

 

[electronicsLearner77]

Give us a little background :

1) Student exercise ?

No. It is real project

2) Your skills, like circuit building experience, prototyping, programming (what languages) ?

I have built some circuits Microcontroller based relay and buzzer circuits, understand little complex circuits with some support. I know C programming language.

3) Basics, like what resistors, capacitors, transistor do and how to use them ?

Yes

4) Ever worked with embedded board/microprocessor ?

Yes, microchip, nxp etc.

4) Project timeline ?

Around 1 month.

 

[electronicsLearner77]

I really liked the circuit and it was simple https://www.ti.com/lit/ds/symlink/lm3420.pdf on page12. I am attaching the circuit, it does not meet my requirements but can i use the concept?

 

[danadak]

Yes it functions as a a charger, the only current being affected is the use of
the LM317 as a constant current source to charge the battery, eg. you do not have
to measure current. But circuit is fixed charge current set by LM317 Rlim. Nominally
one charges at .5C, so depending on pack the cons current source should be adjusted
one would think. There are finer points to charging as this article points out. All the
more reason to make the charger intelligent.

A Designer's Guide to Lithium (Li-ion) Battery Charging

This designer's guide helps you discover how you can safely and rapidly charge lithium (LI-ion) batteries to 20%-70% capacity in about 20-30 minutes.

www.digikey.com

You can do a design with an Arduino in a control loop.


Regards, Dana.

 

[bertus]

Hello,

Also this microchip page might help:

Battery Charging Fundamentals

Battery Chemistries, Terminology, Profiles and Charging Topologies for Real-World Products

mu.microchip.com

Bertus