BQ25300: Power management forum

Stefano Pelizzari

Part Number: BQ25300

Hello,

I'm designing a board with BQ25300 in power path configuration. I'm not sure what's function of diode that connect VBUS to Q4.G.

Is it used to compensate for the drop on Q1? Wouldn't it be better to connect VBUS directly to the Q4 gate?

In any case, I'm fine with putting it but I'm undecided between a Schottky (e.g. PMEG3010EH) or a silicon (e.g. 1N4148).

Thanks for any suggestions
Stefano

over 1 year ago

0 Stefano Pelizzari over 1 year ago

Prodigy 40 points

Addendum: If I were to put a diode with too high Vf I could bring Q4 into conduction. Right?

0 Ning T over 1 year ago in reply to Stefano Pelizzari

TI__Guru 57341 points

Hi,

The idea is that when VBUS is removed PFET Q4 turns on to supply VSYS from the battery; when VBUS is plugged in PFET Q4 turns off and VSYS is supplied from VBUS/PMID. It is fine as long as your design may achieve the idea.

Thanks,

Ning.

0 Stefano Pelizzari over 1 year ago in reply to Ning T

Prodigy 40 points

Hello Ning. Ok I understood the function, but what kind of diode I've to use? Standard silicon or Schottky?

Thanks

Stefano

+1 Ning T over 1 year ago in reply to Stefano Pelizzari

TI__Guru 57341 points

Stefano,

Please use Schottky.

Thanks,

Ning

0 Stefano Pelizzari over 1 year ago in reply to Ning T

Prodigy 40 points

ok. Thanks