BQ25122: bq25122 / Use with no buck converter

S.Satoshi

Part Number: BQ25122
Other Parts Discussed in Thread: BQ25120A

Hi,

Now the customer is looking for the linear charger with I2C interface but they don't need integrate buck converter. They would like to use external buck converter to regulate system voltage.

Then can you recommend following usage? I just wan to recommend bq25122 as linear charger function.

Not use buck converter and leave open the related pins, VINLS, SYS and SW.
Powering external buck converter from PMID.

Best Regards,

Satoshi / Japan Disty

over 7 years ago

0 Robin Tang over 7 years ago

TI__Prodigy 670 points

It's OK to power the external BUCK from PMID pin, but you don't need open the VINLS pin, because this is the internal LDO/Load Switch input, you can connect the external BUCK output to this pin if you want to use the LDO.

0 S.Satoshi over 7 years ago in reply to Robin Tang

Guru 21685 points

Hi Tang,

Thank you for your comment. Can we left open the VINLS pin if we do not use internal LDO/Load SW also?

Best Regards,
Satoshi

0 Robin Tang over 7 years ago in reply to S.Satoshi

TI__Prodigy 670 points

Hi Satoshi, yes, you can do that if you don't use it.

0 Robin Tang over 7 years ago in reply to Robin Tang

TI__Prodigy 670 points

Hi Satoshi, pls add a inductor on the SW pin, BQ25120A will not work if no VSYS.

Thanks,

0 S.Satoshi over 7 years ago in reply to Robin Tang

Guru 21685 points

Hi Tang,

The customer may not want to add inductor if they don't need to use buck regulator function. Do you think it will be OK if powering Vsys from VBUS or battery externally?

Best Regards,

Satoshi

0 Robin Tang over 7 years ago in reply to S.Satoshi

TI__Prodigy 670 points

Hi Satoshi,
No, they need add the external inductor. Thanks,

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BQ25122: bq25122 / Use with no buck converter