BQ24105: LiFePO4 Charger.

Pang

Expert 2415 points

Part Number: BQ24105
Other Parts Discussed in Thread: BQ25071, BQ24171, BQ24650

Hi,

I'm considering to use this BQ24105 to charge LiFePO4 batteries and my specs as below.

Battery charger specs:

Battery Chemistry: LiFePO4

Vin: 12V

Number of cells: 3 in series

Icharge: > 1A

Control Interface: standalone

Can you advise this is good or Ti have other better parts?

over 7 years ago

0 Steven Bangdiwala over 7 years ago

TI__Expert 8690 points

Hi,

What is the max charging current?

Can you provide a datasheet for the battery cells you will use?

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi,

The max charging current is 1A, currently I do not have the datasheet.

0 Steven Bangdiwala over 7 years ago in reply to Pang

TI__Expert 8690 points

Hi,

For a single cell LiFePO4 battery, you can use the bq25071. As for multi-cell LiFePO4 charging, we have the following app note that can help: www.ti.com/.../slua565.pdf .

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi Steven,

I would like to know whether BQ24171/172 can be used to charge LiFePO4 other than BQ25071?

0 Steven Bangdiwala over 7 years ago in reply to Pang

TI__Expert 8690 points

Hi,

The bq24171 should be able to work at 3.6V for LiFePO4, but the recharge threshold will stay at 80mV below regulation. It will be tricky to include the 200mV recharge threshold on the bq24171 because it blinks when it has a fault, whereas the bq24650 has two different STAT pins with defined ON and OFF state.

Looks like the bq24105 can be used to mimic the same behavior that bq24650 has.

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi Steven,

Does it mean that the differences between BQ24171 and BQ24105 is on this matter (recharge threshold)? Or it has other differences?

0 Steven Bangdiwala over 7 years ago in reply to Pang

TI__Expert 8690 points

Hi,

It depends on the STAT behavior. The STAT1 and STAT2 behavior for bq24105 is similar to bq24650, plus it also uses FB to measure battery voltage. This allows you to use the same methods explained in the app note www.ti.com/.../slua565.pdf but with the bq24105, which has integrated FETs.

Regards,
Steven

0 Pang over 7 years ago in reply to Steven Bangdiwala

Expert 2415 points

Hi Steven,

After checking through there's no major differences on BQ24171 as I can see that the recharge threshold voltage regulation can be adjusted through external N Mosfet from the mentioned application notes.

Please confirm.

0 Steven Bangdiwala over 7 years ago in reply to Pang

TI__Expert 8690 points

Hi,

I am concerned about the STAT logic. STAT1 and STAT2 on bq24105 logic is the same as the bq24650 logic. STAT on bq24171 can blink, which will change the recharge threshold every 2 seconds if there is charge suspend, battery overvoltage, input overvoltage, timer fault or battery absent.

What feature from the bq24171 makes you want to use it instead of bq24105?

Regards,
Steven

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BQ24105: LiFePO4 Charger.