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BQ24232: BQ24232 not output at VOUT when battery into low power protection

Part Number: BQ24232

Hi Ti team.
We are working on BQ24232. Now we have some situation as below.

Situation 1: Not working situation
Connector EN1, EN2, CE to to GND and ILIM is floating(NC).
When battery into low power protection mode(measure battery voltage is 0V).
Plugin 5V into bq24232 VIN. The VOUT doesn't output voltage.
Means system not bootup when external power supply input.
According to the SLUS821J –OCTOBER 2008–REVISED MAY 2017 datasheet chapter 8.1, " This feature reduces the number of charge and discharge cycles on the battery, allows for
proper charge termination, and enables the system to run with a defective or absent battery pack. "
Bq24232 allow provide vout even without battery.

Situation 2: Working situation
The different between situation 1 and 2 is connect EN1 to VOUT with 10Kohm resistance.
BQ24232 could provide vout without battery(or low power protection battery) .
It also disable battery low power protection and keep charging the battery.


Why the situation 1 couldn't works?

Thanks

  • Hello Jax,
    Can you share your schematic. Also do you have a scope capture of the BAT pin when VIN is present.
  • i Raheem

    Thanks for your reply.

    Please refer to the attached pictures.

  • Hello,
    Can you elaborate on the battery low power mode. Why is the voltage 0V? Also is there any load on out?
  • Hi Raheem

    VOUT loading was about 100mA.
    BQ24232 was normal output VOUT at first before battery voltage use down to 2.4V.
    Battery protect board was cut the battery output when the battery voltage down to 2.4V.
    After that, BQ24232 VOUT status was like Situation 1.
    The only way to disable battery Over discharge Protection is present 4.2V at least to enable protect MOS.
    The correct action in BQ24232 is output VOUT when VIN present and try to detect battery no matter battery exist or not.
    But it doesn't do that...any idea about this issue?
    BTW, this incorrect situation seems after over discharge protection happened.
    Thanks

  • Hello,
    This is expected behavior. When the battery is absent, due to the protector opening, the system will be supplied from IN. Since your configuration has limited the input to 100mA and your load is 100mA, the output will go into short circuit protection. Since the device is in output short circuit, the battery detection routine is not run. I'll suggest increasing the input current limit above the system load to prevent this.
  • Hi Raheem

    We will fix this issue at next hardware version.

    Thanks for your supported.

    Jax