BQ25606: Battery not present and current limit

Massimo Romano

Part Number: BQ25606

Good Morning

I would like to power a system from SYS pin.

How can i force the "unknown power adapter" status in the circuit?
Also i noticed that if i draw more than 0.2A (is the start-up input current limit) from SYS and battery isn't present the circuit shut down and restart (loop)---> Is anything i can do to forse the circuit as "buck regulator" without battery?
I would like to use it as main power supply even if battery isn't good. But i'm unable to force it to ILIM status (380Ohm) and it shut-downs every time i draw too much current on start without battery.

Thanks

over 4 years ago

0 Ricardo over 4 years ago

TI__Genius 10385 points

Massimo,

Floating the D+ and D- lines will result in the unknown adapter condition. This will allow you to set the input current limit by ILIM and allow you to draw a larger system load. Let me know if this resolves your issue.

Best Regards,

Ricardo

0 Massimo Romano over 4 years ago in reply to Ricardo

Prodigy 150 points

Thanks for reply.

However i already tested it with floating pins, the problem seems different. On start-up condition (0.2A) the circuit connected to SYS absorb too much and seems that BQ25606 shuts down. So i'm unable to reach the ILIM status.
Also the battery is actually not connected to the system.

Thanks

0 Ricardo over 4 years ago in reply to Massimo Romano

TI__Genius 10385 points

Massimo,

If you remove the system load at start up, allow VSYS come up, and then apply the 200 mA load does the issue persist?

Thanks,

Ricardo

0 Massimo Romano over 4 years ago in reply to Ricardo

Prodigy 150 points

Yes the issue persist. However 0.2A is the start up condition, after this if i apply a heavier load, i can reach 0.5A as expected with input limit 500mA. If i go further (i expect current limit of 1A) e.g. 0.6A on Vsys, the circuit shuts down and return to 0.2A status.

---->D+/D- floating and Rlim 380Ohm

Thanks
Massimo

0 Ricardo over 4 years ago in reply to Massimo Romano

TI__Genius 10385 points

Massimo,

Could you please attach your schematic?

Thanks,

Ricardo?

0 Massimo Romano over 4 years ago in reply to Ricardo

Prodigy 150 points

Hello Ricardo, this is the schematic, i tried it with different values (e.g. Rlimin =380). However we found a solution that meet our needs without using the BQ25606. When i will have a minute (in the 2021) i'll try to figure out why it isn't working as expected. Thank you for your time, maybe if i find out what is wrong with my design and maybe i will use on a different project

0 Ning T over 4 years ago in reply to Massimo Romano

TI__Guru 52861 points

Hi,

FYI. Please visit https://e2e.ti.com/support/power-management/f/196/t/890626 for BQ25606: Schematic Review and PCB Layout Design Tips.

Additional Information including FAQs is available http://www.ti.com/lit/an/slva924/slva924.pdf Designing A Standalone Single Cell 3-A Charger with the bq25606.

Hope the information are helpful.

Thanks,

Ning.

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BQ25606: Battery not present and current limit