BQ25896: About TS application

eiven wu

Prodigy 215 points

Part Number: BQ25896

Dear

I see the application of TS on the datasheet. the temperature range are 0~60 degree C.

how to design the temperature(T1-T5) from 0 to 45 degree C?

EX: For my understand: Assume T5 -->60 degree C =2.996Kohm Change it to 45 degree C =4.867Kohm

Is it ok for my understanding?

over 6 years ago

0 Jeff F over 6 years ago

TI__Guru**** 165886 points

Eiven,

Yes, you can choose T5 to be whatever temperature that you want by selecting the corresponding thermistor value at that temperature. However, the JEITA WARM threshold will change to a lower voltage which you can compute here: www.ti.com/.../slurax7. You can disable JEITA WARM using REG09b4.

0 eiven wu over 6 years ago in reply to Jeff F

Prodigy 215 points

Dear Jeff

got it. thanks.

0 eiven wu over 6 years ago in reply to Jeff F

Prodigy 215 points

dear Jeff

I use EXCEL to calculate the RT1 and RT2.

I got the negative resistor.

Do I have some thing wrong?

0 Joel Hernandez II over 6 years ago in reply to eiven wu

TI__Mastermind 25800 points

Hey eiven,

A negative value for the resistor calculation means the combination of TCOLD and THOT thresholds with the give NTC thermistor resistance cannot be achieved. I would suggest choosing a different NTC thermistor with different Beta constants or a different/wider temperature window.

Regards,
Joel H

0 Ning T over 6 years ago in reply to eiven wu

TI__Guru 57341 points

Hi,

You may try to set R_HOT=45C instead.

Thanks!
Please click "This Resolved my issue" button if this post answer your question.

0 eiven wu over 6 years ago in reply to Joel Hernandez II

Prodigy 215 points

Dear Joel

thanks your reply.
I know change the thermistor with different beta constants.
our customer provide the battery to us. We can not request to change the thermistor.
thanks.

0 eiven wu over 6 years ago in reply to Ning T

Prodigy 215 points

Hi.
it is ok on 45C.
I need to discuss with our customer change the protection temperature.

thanks.

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BQ25896: About TS application