Npm1300 bypass for speaker

[SoukTi]

I'm building a system with onboard stereo speakers that can take a maximum of 1,4A when operating at low battery voltage. Can I safely
bypass the npm1300 and directly draw power from the battery without disturbing the charging algorithm of the npm1300, I have an external fuel gauge
so I don't need the internal fuel gauge to be accurate.

[Sigurd Hellesvik]

Hi,

I have one question to understand your case better:

What is the plan for GPIO4 in your design?

Regards,
Sigurd Hellesvik

[SoukTi]

GPIO4 can be used to enable and disable the boost, so I just use the npm1300 as an IO-expander.

[Sigurd Hellesvik]

I asked devs about this, and they say:

"

I think there are several potential issues here:

• Normally 150 mAh batteries aren't happy about 1.4 A discharge currents. Perhaps this particular battery is designed for it?
• Assuming the speakers can play at any time, including when the npm1300 is charging the battery, there could be corner cases where the charger state machine gets confused by additional load on vbat.

I think it would be a better design to connect the boost converter to VSYS, and limit the current to be within nPM1300 battery discharge limits (1 A).

"

[SoukTi]

The actual battery is 600mAh, its just 150mAh that I would like it to start working. Assuming we disable the charging before playback can we then use the bypass design.

[SoukTi]

Ofcourse we would want to reneable the charging after the playback has finished

[Sigurd Hellesvik]

SoukTi said:

suming we disable the charging before playback can we then use the bypass design.

As long as charging and playback do not happen at the same time, this sounds fine to me.

[SoukTi]

Ok, thanks, you can close this ticket

[Sigurd Hellesvik]

Devs add:

"I would say it is best to try it out and see how it works with empty/full battery etc. Anyway it is not really the intended/designed use case and there can be surprises. I don't see any obvious show stoppers with this case if they don't really care about the fuel gauging. "