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STM32f4 + standbymode : need idea

Question asked by ASSAAD on Aug 20, 2016
Latest reply on Aug 21, 2016 by ASSAAD
Hello ; 
I am using STM32F405 in my device ; I have some problem to configure the device in very low power mode ; 
The device should work from 18V/5000mah battery . 
The device should do selftest everyday : I use RTC alarm to wakeup from standby mode. 
The device should give an alarm if the battery is not connected ; 
what I do now is I charge a supercap and put the device in standbymode ;   the supercab and teh battery are connected to LDO  that power the STM32F4 ; 
STM32F4 is in standby mode either wakeuo by RTC alarm  very one hour to check if the battery removed or not  either wake up by a wakeup button for normal operation of teh device . 
I need the total current being consumed  from teh battery to be less than 100uA while I know the standby mode of  stm32f4 is about 20uA  ( max ) .  but I am getting 800uA ! ; I think it is due to the supercap or to the LDO ; 
But I have to put LDO ; 
DO you sugegst any other idea for this issue ? 
Down is the  shematic of the power 



standbymode.jpg

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