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BQ25750: question

Part Number: BQ25750
Other Parts Discussed in Thread: BQ25751, TPS4800-Q1

Tool/software:

1. 캡처된 콘텐츠 중 BQ25750_Design_files의 내용을 확인하려면 어떤 도구를 사용해야 하나요?

2. BQ25750를 사용하여 직렬로 연결된 12Vx6(총 72V) 납산 배터리용 회로를 구축하려고 합니다. 참조 할 수있는 예가 있습니까?

  • Hello Park Jiho,

    Thanks for working with this.

    I ran your questions through a translator. I've copied and pasted the translated questions to make sure we are on the same page.

    1. Which tool should I use to check the content of BQ25750_Design_files of captured content? 

    The BQ25750 design files were created in Altium

    2. You want to use BQ25750 to build a circuit for a 12Vx6 (72 V total) lead-acid battery that is connected in series. Is there an example you can refer to? 

    I would recommend using the BQ25751 IC. The BQ25751 IC is the lead acid charging variant of the BQ25750 and the max battery voltage of the BQ25751 is 70V. For the power path, I recommend not using the BATFETs. I recommend using an external load switch to handle the power-path switchover from the input voltage to the battery voltage.

    Will your system work with the batteries slightly undervoltaged?

    What charging current does your system need?

    Let me know if this makes sense and let me know if you have any questions about this.

    By the way, we also have a FAQ for the BQ2575X part family and a FAQ for the BQ25750 power-path switchover.

    Best Regards,
    Ethan Galloway

  • Thank you for your reply.

    I have some questions, so I'm writing to you again.

    1. We want to charge 6 Lead Acid batteries with MAX Voltage: 83V, Floating Voltage: 79V, Charge Current 1A. Is there any problem with using the BQ25751 you recommended?
    2. I wonder why you recommended using an external load switch.
  • Hello Park Jiho,

    1. The BQ25751 won't be able to charge above 70. You may need to go to a different battery charger or battery for your system.

    2. A power-path switchover of 80V will quickly overwhelm the safe operating area of normal FETs. You'll need much larger FETs to handle an extremely large potential in-rush current. An external load switch should be able to drive the much larger FETs. As an example, you might be able to use a load switch like the TPS4800-Q1.

    Best Regards,
    Ethan Galloway