BQ25756E: Fan Operation with no battery and power supply

Ido David

Part Number: BQ25756E
Other Parts Discussed in Thread: TPS25751, BQ25756

Tool/software:

Hi everyone,

In my design, I am using USB-C connector, TPS25751 IC, and BQ25756E IC. A fan is connected to the output of the BQ25756E in parallel with the battery pack.

Could someone please clarify: if I connect the power supply via USB-C (which connected to TPS25751 input) but no battery is connected, will the fan still be able to turn on and operate normally?

Thank you for your help!

Ido.

8 months ago

0 Ethan Galloway 8 months ago

TI__Mastermind 30615 points

Hello Ido,

It will depend on how much current the fan uses.

I would recommend to set EN_TERM=0 and EN_PRECHG=0 on the BQ25756 to operate a DC load while there is no battery. You'll have to check if the TPS25751 allows these bits to be set.

Best Regards,
Ethan Galloway

0 Ido David 8 months ago in reply to Ethan Galloway

Prodigy 65 points

Hi Ethan,

Thank you for your help!

The fan consumes a maximum of 0.44A. I can control both EN_TERM and EN_PRECHG. If I set them to 0, does that mean the fan will operate properly even without a battery connected?

Best regars,

Ido

+1 Ethan Galloway 7 months ago in reply to Ido David

TI__Mastermind 30615 points

Hello Ido,

Thanks for being patient with this. A lot of us were out on vacation over the new year.

Yes, the load will be able to operate with these bits set to 0 even if there's no battery connected.

Best Regards,
Ethan Galloway

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BQ25756E: Fan Operation with no battery and power supply