• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 64 subscribers
  • Views 328 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

BQ24012: Charging and Junction temperature

bas van rossem
Prodigy 10 points
Part Number: BQ24012
Other Parts Discussed in Thread: BQ24040, BQ24090, BQ24041, , BQ24133, BQ24010, TPS62130

Hello,

The absolute maximum junction temperature is specified as 125°C while the maximum storage temperature is specified as 150°C.

In the text of the datasheet it is stated that the devices stops charging when the junction temperature increases above 155°C and resumes charging when the temperature falls below 130°C.

Based on these maximum ratings I expect that the device indeed stops charging above a certain temperature, but I fear that it will never resume charging :-( or am I missing something?

  • 0
    TI__Guru* 75786 points

    Hello

    This is correct the device has thermal protection at 150C that will disable charge.

    Later design have thermal regulation that starts at 125C and will regulate output current based on junction temp. See BQ24040 and BQ24090.  They also have a charge disable at 155C.

  • 0 in reply to Bill Johns
    Prodigy 10 points

    Hi Bill,

    I'm a colleague of Bas and we have in our current design the BQ24041 but getting into the limit of 6.5V overvoltage protection. We would like to use it with a maximum input voltage of 15V.

    Of course this 15V will be with a lower current then it would be at 6.5V. But this isn't possible with the BQ24041 because of the over voltage protection (same goes for the BQ24090).

    But it should be possible with the  BQ24012 but like Bas mentions if we read the datasheet correctly the charger stops charger at 155C because it is broken and won't recover (see absolute maximum of 125C).

    We would like to have a charger that is capable to be charged with an input voltage of max 15V and lowers the charge current (not sure what is possible if we insert a current to Iset resistor from the input for example?)

  • 0 in reply to Maarten Leeters
    TI__Guru* 75786 points

    Hello

    A couple of options to consider:

    1.) Change to a Switch mode charger -- Switch mode charger have a wider Vin and higher efficiency.  the BQ24133 has internal mosfets and max Vin of 17V.

    2.) Change to BQ24010 or 014 -- This version of the device has a TS pin input for measuring battery temp.  But this could be used to monitor temp on the PCB near the device with and NTC resistor.

    3.) Reduced charge current -- Do not recommend "insert a current to Iset".  But a resistor could be added in parallel to R-ISET and switch in or out with a mosfet based on desired charge current dependent on temp.

    4.) Adding a wide Vin buck converter before the battery charger to reduce input voltage,  possibly the TPS62130 followed by BQ24040.