• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 63 subscribers
  • Views 521 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.

BQ24171 burn out in overloading question?

Chen Bogey8
Mastermind 9990 points
Other Parts Discussed in Thread: BQ24171

Hi Sir 

We set Idpm 2.4A by setting R4 100k ohm and R5 17.4k ohm.

The function work when the battery connect.

May we know if we remove battery, and force adding System loading what will be happen in BQ24171?(Adapter power capacitor is enough because we use power supply.) 

we try it in customer board, but the BQ24171 will be damaged when we set Idpm in 2.4A, remove battery, force system loading at 3.5A.

is it normal?

                                                                                                                        Bogey 

  • 0
    TI__Genius 11480 points

    Hi  Bogey,

    IDPM will reduce charge current (thus reducing the required input current), that way the adapter can make powering the system a priority. It is not an input current limit.

    What is your power supply voltage? What part is getting damaged? My guess right now  is that the large load step is causing an overshoot or ringing, causing damage on either VCC, ACP/ACN, or PVCC. 

  • 0 in reply to David Wiest Jr
    Mastermind 9990 points

    Hi Sir

    My power supply voltage is 5v.

    The ACP/CAN,PVCC seem to be normal but SW pin short to GND.

                                                    Bogey

  • 0 in reply to Chen Bogey8
    TI__Genius 11480 points
    SW is shorted to ground on the damaged unit?

    If you can capture a scope trace of SW when damage occurs, I think that will tell us if an overshoot is damaged the low side FET.

    Adding an RC snubber at SW will reduce ringing, as well as adding a small (0-5ish ohms) series resistor at BTST. You can also improve overshoot/ringing through imrpoving PCB layout.