Battery charging problem

Would you give more detail about "over charging and under discharge protection"? Thanks

All Texas Instruments battery charger ICs have built in protection circuitry to protect against over and under charge conditions that could damage the battery.  The TI web page provides a good selection tool to help narrow down your battery charger IC.

http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=411&uiTemplateId=NODE_STRY_PGE_T

You should also consider working with your local Texas Instruments Distributor.  They can help you with your IC selection and can help with selecting other components for your system.

http://focus.ti.com/general/docs/distributorinfo.tsp 

Dear Wang,

Thanks for your reply.

I have read details of lithium ion battery characteristics. It mentions that if it is charged more than 3.7v then battery perfomance will be degraded. So, IC should protect battery from charging after it is 100% charge.

Same technical artical states that if battery is used below 2.2v then also its perfomance decreses. So, there should be some indication for 2.2v.

Dear michael,

Thanks for reply.

I have gone through device search. But I am confused for which one select. As each is giving 4.1v output and my battery is of 3.7v.

Can you suggest some IC ?

The Lithium-ion battery should be charged to 4.2V. But, please double check it with the battery manufactory.

We don't indicate 2.2V. In general, the battery pack should provide that protection. In charger side, the body diode of BATFET still can connect BAT to system even battery voltage is very low and BATFET is off.

Hiren,

Most lithium ion batteries' nominal voltage is stated as 3.7V.  This is usually the average voltage that the pack will be as it is discharged.  This voltage varies with the remaining capacity in the pack and is usually kept between 3 and 4.2V in normal operation.  Most lithium ion batteries (check with your manufacturer to be sure) are charged with a CC/CV algorithm, where CC is the batteries' C rating and CV is the full charge voltage of the cell.  This should be explained in most, if not all, of our charger datasheets.  For most lithium ion batteries, their full charge voltage is 4.2V.

I suggest you read up a little on lithium ion batteries in general and how they are charged: http://en.wikipedia.org/wiki/Lithium-ion_battery

The choice of charger depends on which battery you pick.

If you have a Li-Ion battery, the 3.7V you reference is not the maximum charge voltage.  The maximum charge voltage is going to be 4.1V to 4.2V.  Be sure to check your battery specification.  A good choice to charge the battery may be the bq24060 or a bq24079T.  Neither will overcharge the battery.  The bq24079T will not let the system overdischarge the battery.

Hiren, can you choose which forum post best answeres your question and mark it as "verified"  If you have specific questions about a charger, it will be good to start a new forum thread.

Thanks,

Dear Michael,

Can I use bq24079T IC as on board battery charger?

I want to use this battery charging as in our Mobile phones, that while charging also your device will work fine.

Dear Michael,

Thank you very much for your such a help.

Thanks again