BQ25895: Will the device break when battery is reverse connected?

Howard Zou

Part Number: BQ25895

I think the answer is that it will break.

My customer has reverse connected the battery to the device. And then they remove the battery, and then repower the device with 5V USB input. Then they will observe 2.8V @ Vbat and 4.1V @ Vsys

Does this mean that the device is broken?

What's the voltage that should be on Vbat pin when battery is unconnected?

over 6 years ago

0 Paul Yeh over 6 years ago

TI__Genius 16185 points

Hi,
Battery reverse connection may damage chip internal ESD protection. So I think your device may already be portion damaged.
From datasheet, this BAT pin min ABS voltage should be -0.3V rating.
No battery condition, our min system voltage should be 3.65V.
Thanks

0 Howard Zou over 6 years ago in reply to Paul Yeh

TI__Genius 12365 points

When no battery is connected, is the BATFET on? Will Vbat=Vsys?

0 Paul Yeh over 6 years ago in reply to Howard Zou

TI__Genius 16185 points

Howard,

I saw Jeff replied this question before. BATFET should be in LDO mode. See below.

you are correct. When battery is unattached, V(SYS)=VSYS(MIN)+150mV. VSYSMIN=3.5V then VSYS=3.65V typical.

Thanks

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BQ25895: Will the device break when battery is reverse connected?