Vbat problem on a STM32F4

[paul-arthur]

Posted on June 06, 2012 at 15:59

Hi,

I'm working on a custom design with in a STM32F4xx. A 420mF capacitor is connected to Vbat. ( with a serial diode and a resistor between Valim and Vbat to charge up the supercapacitor ).The system power off it still 600mV to Valim if the supercapacitor is connected, 0V if not.So I'm a bit confused,...Any ideas ?Thanks, #vbat

[Tesla DeLorean]

Posted on June 06, 2012 at 19:54

Sounds familiar, suggest you call your FAE/rep if you want an answer from ST.

https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Vdd being held at 0.7V with backup battery fitted&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=96

[paul-arthur]

Posted on June 07, 2012 at 10:25

Ok thank's.

[John F.]

Posted on June 11, 2012 at 17:02

Any more information on this please? IS there a problem with the VBat switching / power leakage on the STM32F4 chip?

[paul-arthur]

Posted on November 12, 2012 at 18:46

hello,

Problem solved ! Please see:

https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Vdd being held at 0.7V with backup battery fitted&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=449

[John F.]

Posted on November 13, 2012 at 10:41

Hi PAM,

Thanks for completing this post. For everyone else (after the system crashes and all the links break) the message was,

''I get it ! In my design PDR_ON was left unconnected. If i pull it up; this probleme is solved !''

Hope that's it!.