• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 484 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.

BQ25150: BQ25150 MR signal when battery not connected

Sara Glick1
Prodigy 150 points
Part Number: BQ25150
Other Parts Discussed in Thread: BQ25120

I noticed that the MR signal oscillates between 4V and ~2.5V when USB is connected to the BQ25150 but battery is not connected. See attached scope shot, the MR pin is labeled "BTN". Is this expected behavior? 

  • 0
    TI__Genius 12485 points

    Hi Sara,

    Long time! (we worked on some BQ25120 and energy harvesting projects a while back)

    Yes that is expected. The device with the /CE pin pulled low by default, sees the battery capacitor and charges it up. When the "charging is complete" it will cut off and the voltage on battery capacitor will collapse below the VRCH threshold. This will in turn enable the charger back. This is the cycle that keeps happening repeatedly. 

    You could disable charging through /CE pin or I2C if you want to disable this behavior. Also having a large capacitor (for bench debug) can trick the device but it is not recommended. 

    Let us know if you have any questions.

    Regards,

    Gautham

  • 0 in reply to Gautham
    Prodigy 150 points

    Hi Gautham, 

    That makes sense! Thank you for the explanation. 

    Thanks,

    Sara