BQ25895: NTC resistor sizing for LIPO batteries

Just a little update, by using the datasheet value and setting VT1 = 73.25% of VREGN and VT5=44.75% of VREGN I have:

so a valuethat are close to the ones reported on the datasheet (5210 ohm and 29870 ohm).

Now from a conservative design perspective, about the cold temperature rising threshold, should not be better use the lower percentual value of 72.75% instead the nominal 73.25%?

Similary, about the VTCO, at the higher temperature the NTC resistance take the lower value, if the threshold is set to the higher value 44.25% the protection should be always inside the max 45°C degree, isn't it?

So a better choice may be to use:

VLTF=72.75%

VTCO=44,25%

with this value we have RT1=5301 ohm and RT2=29408 ohm.

Make sense?

Thanks and best regards.

F.

Thank you Ning,

just a question, about the VREGN into the spreadsheet is used 6V, In my design the VBUS (input voltage) will be equal to 5V so from datasheet I think that VREGN will be equal to 4.7V÷4.8V, and also VVREF into the equation should be equal to VREGN, changing 6V to 4,8V, but the calculated resistors value are the same as evaluated by using VREGN=6V, so the resistor values seems to be not related to the VREGN I think because into the equations I've the ratio between VVREF and VTCO and between VVREF and VLTF, I'm right?

Thanks and best regards.

F.

Thank you Ning to point me around this thread,

hence, at the end, this seems to me that is not important the VREGN value because into the equation we have a ratio that is fixed inside the chip then the two resistors value are effectively not depending to this voltage, I'm right?

Best regards.

F.

Thank Ning!