STM32MP135f VBat Current Consumption

[GokhanK]

Hello,

We are trying to run Tamper block in VBat (Vsw) mode. When we powered off the device, Vbat pin consumes 3 - 5uA from the battery as specified in device user manual.

As we understood from the documentation, the source of Vsw domain (either Vbat or VDD) is switched automatically by internal switch harware, so zero power consumtion is expected from battery when VDD is on.

In our custom board, when the board is powerd-up, VDD is on, VBat pin's power consumtion from battery increases up to 50-60uA.

Any recomendation about hardware or software would be very helpfull.  

-The PDRON pin is pulled-up to VDD on the schematics.  

- Battery is CR1216 - 3V Lithium Manganese Dioxide

- Battery is connected to the Vbat pin directly, no serial diode,resistor, etc...

- Battery cahrging feature is not enabled form device tree.  

[AScha.3]

Hi,

check: is vbat divider -> ADC , OFF ? Otherwise you see its current added to the RTC consumption.

here from U5 rm: ADC ->

[GokhanK]

Hi Ascha,

Thanks for the quick reply.

I tried to disable the ADC2_VBAT on optee device tree (I think disabling the &adc_2 node and subnodes would be enough). 

It helped, consumption decreased from 50uA to 30 uA. But it is not enough. We expect "~0" when device powered on..

Do you have any other recommendation.

&adc_2 {
vdda-supply = <&vdd_adc>;
vref-supply = <&vdd_adc>;
status = "disabled";  //LETTA okay -> disabled
adc2: adc@0 {
status = "disabled"; //LETTA okay -> disabled
channel@15 {
reg = <15>;
label = "vbat";
};
};
};