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Original question:

TPS63020: -

TPS63020: Problem with precharging using BQ24060 and TPS63020

Bart Bargenquast
Prodigy 10 points
Part Number: TPS63020
Other Parts Discussed in Thread: BQ24060,

Tool/software:

Hi

I am using the BQ24060 to charge a 250mah battery on +VIN.

Also on +VIN, I have my 3.3V regulator circuit using a TPS63020DSJR.

The charging works as expected except when it comes to prehcharge/trickle charge.

This feature does not work. When I disconnect the TPS63020DSJR, only then precharging works.

Why does this happen? Is it because the prehcharge current is taken by the regulator + load from the rest of the circuit? If so, how do I prevent this.

Thanks.

  • 0
    TI__Mastermind 18540 points

    Hi Bart,

    I'll check and reply to you by tomorrow.

    Regards

    Lei

  • 0 in reply to Lei Zhong
    TI__Mastermind 18540 points

    Hi Bart,

    Sorry I'm a little confused about your description. 

    Do you mean that when the TPS63020DSJR is disconnected, and remain BQ24060 and the battery only, then the charging does not work normally?

    Regards

    Lei

  • 0 in reply to Lei Zhong
    Prodigy 10 points

    With both the BQ24060 and TPS63020 on the board, charging works normally as expected.

    However, in the case where the battery is 0V, and precharge is required, the circuit does not work.

    However, when I remove the TPS63020, the BQ24060 is able to precharge the battery and bring it back to life.

    I'm confused if there is something wrong with either my BQ24060 circuit or TPS63020 circuit which is resulting in the board not being able to precharge.

    Your reply is much appreciated.

    Thanks

  • 0 in reply to Bart Bargenquast
    TI__Mastermind 18540 points

    Hi Bart,

    If my understanding is correct, then only when the battery is 0 and the TPS63020 is on board, then the charge doesn't work normally.

    It's really strange! Since when the battery is 0, which is the Vin of the TPS63020, the TPS63020 is still in shut down mode. It's input and out is disconnected. That means, although the TPS63020 is on board, there will be no impact to the BQ device and the battery.

    For double confirm, you may try the condition that TPS63020 is on the board and battery is 0, and pull down the EN of the TPS63020 to zero. Then check whether the charge works normally.

    Regards

    Lei