BQ79606-Q1: Datasheet Error(NTC sensor circuit Resistor value calculation equation error)

Caesar Wang

Part Number: BQ79606-Q1

As the Pic, which show in the BQ79606 datasheet page238:

As you know, the NTC resistor will decrease during temperature increase. It means RHOT is less than RCOLD.

Based on this, R2 is negative value and can't calculate the R1. Please recheck it.

0 Andy Li55 over 6 years ago

Hi Caesar,

If the NTC is connected between GPIO and AVSS, then RHOT will be less than RCOLD as you said.

If the NTC is connected between TSREF and GPIO, then the story is opposite.

Please be aware that the above equation is based on NTC connected between TSREF and GPIO.

Andy

0 Caesar Wang over 6 years ago in reply to Andy Li55

ear Andy；

Good morning.

Thank you for your support.

I think there were some misunderstand between us. The detial calculation value is as below. Please reference and re-consider my question.

Thank you.

0 Andy Li55 over 6 years ago in reply to Caesar Wang

Hi Caesar,

Sorry for delay due to being on business trip.

I will get back to you by tomorrow.

Thanks!

Andy

0 Andy Li55 over 6 years ago in reply to Andy Li55

Hi Caesar,

I do understand your question.

If the NTC is connected between GPIO and AVSS, then RHOT will be less than RCOLD as you said.

If the NTC is connected between TSREF and GPIO, then the story is opposite. Right?

I would suggest that we have to modify the DS, switching RHOT and RCLOD in R2 equation.

Andy

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