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BQ24075: Overheating problems with a single cell Li-Ion battery

Jonathan Geronga
Expert 7930 points
Part Number: BQ24075
Other Parts Discussed in Thread: , LM66100

Hi Team,

The customer is using bq24075 battery charger and have a question about NTC

If they have a battery with 45° allowed temperature during charge, but bq24075 specs on BATTERY -PACK NTC MONITOR set trip point of 50° while charging the battery. They would like to understand if they have overheating problems with a single-cell Li-Ion battery using this device

Their battery specs are of 45°C max T during charge. Do we have a suitable product for their battery allowed temperature or can they use the bq24075T, that is the voltage- based TS?

Other questions concerning the power path Vo(reg):
if their VIN =5V (from usb ), is the output voltage on pin10/11 equal to:
5V-VDO(in-out) = 5V-300mV ?
Or is always VOUT=5.5V regulated output discardless Vin value?
because they need a OR-Ring load switch (realized by two LM66100 with Vin max 5.5V) between BQ24075 output and a second power supply so they need to be sure that battery charger output voltage is less than 5.5V

Please let me know if you have further questions with the customer to support this inquiry.

Thanks,

Jonathan

  • 0
    TI__Mastermind 23170 points

    Hi Jonathan,

    You can take a look at the NTC calculator to see about adding some resistors that can modify the temperature thresholds based on NTC data and the desired hot threshold. The BQ24075T will have more flexibility in adjusting the temperature range for battery charging. Is there a specific battery temperature range they would like to set?

    The BQ25075 has an output regulation of 5.5V that we specify for the following condition:

     VIN > VOUT + VDO(IN-OUT)

    Should the voltage at the output start to fall to VDPPM, the devie will enter DPPM mode and reduce the charge current to keep the voltage at VDPPM (which for this device is 4.3V)