STM32L562E-DK board current consumption

[ABois.11]

Hello everybody,

I am developing an embedded application using STM32L562E-DK which autonomy has to be greater than 3 months.

My problem is that I remarked that the board consumption (not including the MCU and its peripherals) is about 120 mA. I precise that I have realized these measurements with VDD disconnected (JP2 OFF) and STLink not powered. This consumption does not depend of the 5V source. It is not compatible with my application, my average current budget is 5 mA.

Is there a way to greatly reduce this current consumption?

Thank you very much for any help!

[TDK]

> Is there a way to greatly reduce this current consumption?

Greatly reduce your clock speed and/or make use of low power sleep/stop modes.

[ABois.11]

Thank you for your answer @TDK​ but the 120 mA I measure are not drawn by VDD but by the 5V power supply. On VDD I measure 1mA with is very satisfying.

So I do not know if I can remove solder bridges or resistors on the board to reduce the consumption, and which ones...

[TDK]

Got it. That board has a lot of stuff on it, it's not really meant for low power applications. I doubt there is a simple way to reduce current consumption with solder bridges. I would either rework the board by remove chips not in use, or consider a different board (nucleo) which better suits your needs. Thermal cameras are great for figuring out which chips are using power, if you have one.

[ABois.11]

Thank you very much for your hint @TDK​. With the thermal camera we have seen most consuming components. The best I have done was to power down all the Powermeter part. Looking at the .PcbDoc file of the board, I determined which components may be interesting to remove. Here is the list:

- R81 (resistor) - Power 5V Led 12

- R65 (resistor) - Power 5V_PM - deactivate 3V3_PM created by U34 from 5V_PM

- R5 (resistor) - VDD power supply of U1 (Low-Power, Stereo Codec with Headphone Amp)

- D8 (diode) - Power 3V_MCU_PM

- BLE module (entire module removed)

- U5 (Dual bit dual supply bus transceiver VDD signal): VDD power supply cut

With these modifications, I measure a current consumption in output of the battery of 2,1 mA instead of 160 mA! The MCU draw 17 uA (Stop 2 mode).

Thank you again @TDK​, my goal is reached!