TPS3619: Backup battery switchover problem

TW Wang

Part Number: TPS3619

I found Vout of TPS3619-33DGKR was not switched to the VBAT(backup battery) when VDD experienced a power drop. Check the attached picture.

When VDD(Ch#1) goes down from 3.3V to 0.8V, the VOUT(Ch#3) seems to follow and track the VDD, Why the VOUT is not switched to the VBAT?

over 2 years ago

0 Patrick Shalton over 2 years ago

TI__Mastermind 28810 points

Hi TW,

Can you ensure that the battery is properly connected to the VBAT pin? Also, do you have a schematic you can share to help diagnose this issue?

Thanks,

Patrick

0 TW Wang over 2 years ago in reply to Patrick Shalton

Prodigy 50 points

Yes, the coin battery is connected to the VBAT properly. Attached is the application schematic. #PFO. #RESET, and #MR pins are not used in the test case.

VDD sometimes has a dip drop because the power capacity of VDD source is not enough. 5V_SYS is always above 5V.

0 Trailokya Rai over 2 years ago in reply to TW Wang

TI__Genius 11401 points

Hi Wang

Patrick is on leave. He will reply to you as soon he returns.

Regards

Trailokya

0 Walter Zollinger over 2 years ago in reply to TW Wang

TI__Genius 9770 points

Hello TW,

Have you disabled the battery freshness seal in the TPS3619? It keeps Vbat disconnected until disabled. Can you disable the seal and repeat the test?

Best,

Walter

0 TW Wang over 2 years ago in reply to Walter Zollinger

Prodigy 50 points

Hi Walter

We never implemented 'Freshness Seal ' steps.

Is there any Vbat disconneted situation besides the 'Freshness Seal ' mode?

Best regards,

0 Walter Zollinger over 2 years ago in reply to TW Wang

TI__Genius 9770 points

Hello TW,

The freshness seal should be the only Vbat disconnect situation.

Best,

Walter

Power management

Power management forum

TPS3619: Backup battery switchover problem