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BQ24630: BQ24630 charge with BQ76920+BQ78350 then burn out

Star Xu
Genius 9645 points
Part Number: BQ24630
Other Parts Discussed in Thread: BQ78350, BQ76920,

Hi 

The customer design with BQ24630 to charge BQ78350+BQ76920. They found it is easy to burn the BQ24630 and its peripheral components.

BQ76920+BQ78350 battery management board is connected with a five series lithium polymer cells (the maximum voltage of each battery is 4.35V)

Attached the schematic for your reference.

3808.电池组.pdf充电功能板.pdf 

where P2 interface is the interface with the battery pack, and the GND of P2 is disable.

Waiting for your reply.

Thanks

Star

  • 0
    TI__Mastermind 21820 points

    Hi Star,

    I am not sure which schematic I should be looking at as the picture and the .pdf file have several differences.

    Can you specify under what testing condition when the IC is damaged and what other components are damaged?  

    Regards.

  • 0 in reply to Tommy Lin
    TI__Genius 9645 points

    Hi Tommy

    Thanks for your reply.

    I used BQ76920+BQ78350 battery management board to connect with a five series lithium polymer battery pack, as shown in the figure.

    Connect the battery pack management board with the motherboard (through P2 interface with four pins, BATT+, PACK -, SMB_CLK, and SMB_DAT). When the battery management board is connected to the motherboard, it will burn the BQ24630 and Q6,R27, as indicated by the arrow in the following figure.

    The lithium polymer battery management board and the motherboard are repeatedly connected/disconnected several times, and the burning phenomenon is easy to reproduce. (The battery pack always has voltage output, and the connection between the battery management board and the motherboard is hot plug)

    Please give some suggestion with this issue.

    Thanks

    Star

  • 0 in reply to Star Xu
    TI__Mastermind 21820 points

    Hi Star,

    This issue is most likely caused by voltage ringing above the absolute max of the device from the hot plug.

    My suggestions will be 1) using the adapter hot plug snubber circuit (see below, but you will need a large resistor as there will be current going through multiple times due to constant hot plug), or 2) use a TVS diode to clamp the ringing (recommended).

    Regards.