STM32 Vbat pin drains battery quickly

[mcgilvra2]

Posted on March 04, 2010 at 05:22

STM32 Vbat pin drains battery quickly

[John F.]

Posted on May 17, 2011 at 13:42

Albert,

I also have an (ST32F103VET6, QFP100) design with a BR1632A 3V lithium coin cell. I am bringing up a board which seems to be working normally. I also have a spare board as yet unused. I just measured the coin cell at over 3V and measured across each of the supply decoupling capacitors on VDD_1,2,3,4 and 5. I measured only 1 or 2mV across the capacitors in each case. Perhaps you have a track or solder whisker bridging from pin 6 to an adjacent pin? Or has your PCB been washed and improperly cleaned leaving a leakage path? Unless we're told differently here, I don't believe there is anything wrong with the ST32F103VET6 part. Are you able to lift pin 6 and see if the drain is into the pin or on the PCB? Sneaking a query in ... saw your adaptation of Chan's FAT on Rowley CrossWorks forum. Any updates? Is it all good? I want to use it in my design. John F.

[mcgilvra2]

Posted on May 17, 2011 at 13:42

John,

Thanks, I'll check for leakage paths.  Latest SD_FAT attached.  It's all good.  I added a global Event flag to log different SD exceptions.  Also commented out a couple lines in f_close that were setting the file date/time; they called get_fattime which I don't implement, I wrote File_SetDateTime for that purpose. Regards, Al

[John F.]

Posted on May 17, 2011 at 13:42

Al,

Thanks for updated files. Please post here when you find the problem that's draining the RTC cell. Good luck. John F.

[John F.]

Posted on May 17, 2011 at 13:42

It also occurred to me that the RTC clock can be output on Tamper pin (TAMPER-RTC/ALARM/SECOND OUT pin) for calibration. This is enabled by setting the CCO bit in the RTC clock calibration register (BKP_RTCCR).

Is this pin enabled and driving into a load? ''PC13, PC14 and PC15 are supplied through the power switch.'' I think this means from VBat when no main power. Function of PC13, PC14 and PC15 depends on the contents of the Backup registers even after reset (because these pins are only reset to default after BOTH VBat and VCC have been zero). John F.

[mmetzger]

Posted on May 17, 2017 at 13:54

Hello,

I have a similar issue. In Standby Mode I measure 1uA which is quite possible with the run of the RTC. When I go back to Run Mode I measure 25uA which drains down the battery too fast.

Any ideas to test something?

Marco

[waclawek.jan]

Posted on May 17, 2017 at 14:52

Which chip? What battery-related functions do you use in your program?

JW

[mmetzger]

Posted on May 17, 2017 at 15:08

Hello,

It’s a ST32F429IIT6 with a CR2032 battery. I use only the RTC and it is all working perfect.

The only thing I’m worried about is the 25uA battery current to the chip in run operation, with standby it is 1uA which seem’s to be ok.

Best regards

Marco

Von: waclawek.jan

Gesendet: Mittwoch, 17. Mai 2017 14:54

An: metzger.marco <mmetzger@bluewin.ch>

Betreff: Re: - Re: STM32 Vbat pin drains battery quickly

<https://community.st.com/?et=watches.email.thread> STMicroelectronics Community

Re: STM32 Vbat pin drains battery quickly

reply from waclawek.jan <https://community.st.com/0D70X000006Su0eSAC

[waclawek.jan]

Posted on May 17, 2017 at 15:11

OK so write a minimal program which does basically nothing else only what you do with the RTC in the program in question, and does not go to sleep.

Still 25uA?

JW

[mmetzger]

Posted on May 22, 2017 at 15:53

Hello Jan,

I tried with a simple program out of the cube and this works perfect. So is there anything configured wrong?

Best regards

Marco

Von: waclawek.jan

Gesendet: Mittwoch, 17. Mai 2017 15:12

An: metzger.marco <mmetzger@bluewin.ch>

Betreff: Re: - Re: STM32 Vbat pin drains battery quickly

<https://community.st.com/?et=watches.email.thread> STMicroelectronics Community

Re: STM32 Vbat pin drains battery quickly

reply from waclawek.jan <https://community.st.com/0D70X000006SzPMSA0