• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 354 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ24074: High Temperature Trip Point

scharppe
Prodigy 150 points
Part Number: BQ24074
Other Parts Discussed in Thread: BQ24072, BQ25120A, BQ25155

Hello,

We’re using the bq24074 to manage a Li-Ion battery pack which incorporates a 10KΩ NTC, B25/85= 3435.

Charging temperature for the battery cell is 0~45℃. This seems to be a somewhat standard charging limitation on most Li-Ion cells. 

From the bq2407x datasheet:

“The bq2407x features an external battery pack temperature monitoring input. The TS input connects to the NTC thermistor in the battery pack to monitor battery temperature and prevent dangerous over-temperature conditions. “

However, we’ve just noticed that the BQ24074 default high temperature cut-off for charging is 50degC, not 45degC and the chip design doesn’t allow for this threshold to be reduced (only extended).

We did see on another thread related to the bq24072 that the bq24072 has been changed to a bq24072T to accommodate the change in cut off temperature. Unfortunately we see no such part substitute for the bq24074. 

Is there any solution to reduce the upper cut off temperature of the bq24074? 

Thanks in advance for your help.

  • 0
    TI__Mastermind 21590 points

    Hello,

    Please take a look at the application note below.

    http://www.ti.com/lit/an/slua955/slua955.pdf

  • 0 in reply to Raheem
    Prodigy 150 points

    Thanks for the prompt reply Sharafadeen.

    Not an ideal solution for a cost sensitive design but solves the problem nonetheless.

    I have a few follow up questions however. Do you have any insight as to the life expectancy of the bq24074?

    Since we are at a point in the project design cycle where it could be possible to change the charger IC, would you suggest migrating to a different family of charger IC? Again not an ideal solution but would rather bite the bullet now rather than later if the bq24074 goes EOL in the near future.       

    Thanks again for your help.

  • 0 in reply to scharppe
    TI__Mastermind 21590 points

    Hello,

    I don't expect the BQ24074 or any device in the BQ2407x family to EOL any time soon as it's a very popular device. Other devices you can take a look at are the BQ25120A and the BQ25155 but those require I2C communication to function. They both have flexible NTC so that issue won't come up. 

    What is your required charge and load current?

  • 0 in reply to Raheem
    Prodigy 150 points

    Thanks for the information. I think after your confirmation that the bq24074 is not in imminent danger of becoming EOL, we will adopt the idea of an external high temperature charging cutoff circuit of some type.  

    Thanks for your help.