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BQ24072: CHG pin low but not charging...

Luis Barbosa
Prodigy 10 points
Part Number: BQ24072

Hi, 

Some devices fails after use.

Chg pin is low ,  PG is low , but there is no battery charging current.

TS is OK, about  0.8v

1) Temperature during charging is very HIGH... could that damage the device permanently ?  

2) Could  GND thermal pad bad soldered damage the device permanently ? 

3) Is it common ESD issues produce this kind of bad functioning ? 

4) Any idea of what's going on?

  • 0
    TI__Mastermind 22210 points

    Hi,

    Welcome to E2E!

    Can you provide a larger version of the schematic? It's not quite clear. Please upload using the INSERT -> IMAGE/VIDEO/file option instead of copy pasting the schematic  Based on what I can see there are a few comments I have:

    • The capacitor on the input is very large compared to what is recommended (1uF to 10uF)
    • Is the capacitor on the output also large?

    What is the charge current being programmed? Do you see the correct voltage at the OUT?

    Best Regards,

    Anthony Pham

  • 0 in reply to Anthony P Pham
    Prodigy 10 points

    The biggest problem is that BQ is permanently damaged.

    Input capacitor is 100nF. 

    Charge current is about 1A  ( Ilim = 910R ) 

    Output capacitor is 10uF , but we have a TPS22965DSGT switching a 330uF. 

  • 0 in reply to Luis Barbosa
    TI__Mastermind 22210 points

    Hi Luis,

    We do list in the pin description that IN needs to be bypassed with a 1uF to 10uF capacitor as previously mentioned. 

    We also require a capacitor on the BAT pin to be in the range 4.7uF to 47uF.

    It does not look like your input current is actually configured for 1A based on the ILIM resistor. If you'd like to set it to 1A, please choose the closest resistor value to 1610 Ohms

    It also does not look like your charge current is configured for 1A but actually 1.5A. If 1A is what was seen, this may be due to the device going into supplement mode early to charge the 330uF capacitor if that is also connected to the output. 

    How has the device been damaged? Is it simply not charging anymore? What occurred when the device was damaged?

    Best Regards,

    Anthony Pham

  • 0 in reply to Anthony P Pham
    Prodigy 10 points

    It simply not charging anymore.

    Changing BQs fix the device.

  • 0 in reply to Luis Barbosa
    TI__Mastermind 22210 points

    Hi Luis,

    It sounds then like the device was damaged. If you make the appropriate changes that I've recommend, this will reduce the probability of damage.

    Please configure the device appropriately and for best IC safety, operate it within the recommended specifications.

    Best Regards,

    Anthony Pham