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High power consumption in low power examples

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Hi St forum

I'm in the progress of creating a peripheral BLE application using the STM32WB55CE on a custom board.

I'm trying to implement low power now, but struggling..

Using the X-Nucleo-LPM01A power monitor board I've measured my current consumption (no low power implemented):

This is not impressive, but expected.

To get a grip on ST low power, I've run various examples on the P-Nucleo.WB55 dev. board, but it looks like the current consumption is very high no matter the example??? I've based my guesses on the Power features application note.

Setup:

All jumpers from STLINK is removed during test.

PWR_STOP2_RTC exampple:

expected ~2.2uA

PWR_EnterStandbyMode:

expected < 1uA.

PWR_SMPS_16MHZ_HSI w/o RF Stack:

??

PWR_SMPS_16MHZ_HSI with RF Stack:

BLE_HeartRate:

not sure.

So the question is:

I'm I missing something vital?

Ideally I would like the application to enter either STOP2 or STANDBY when no BLE central is connected.

regards

STM32WB series

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Remy ISSALYSBest answer

ST Technical Moderator

Hello,

Using the X-Nucleo-LPM01A power monitor board to do consumption measurement, it's a good strategy. To avoid overconsumption, try to supply the P-Nucleo.WB55 only with 2 wires from X-Nucleo-LPM01A :

> The first one from AREF pin of X-Nucleo-LPM01A to VDD pin of JP2 P-Nucleo.WB55 (remove the jumper)

> The second between GND pin of X-Nucleo-LPM01A and GND pin of P-Nucleo.WB55

In addition, remove all jumpers on JP5 and don't power the P-Nucleo.WB55 with USB cable.

Use BLE_HeartRate example which allows to do STOP2 low power mode.

Best Regards

MM..1

Super User

How is real measurement?

KMeld.1Author

Associate III

I'm not 100% on what is defined by "real" meassurement...

BUT, I've used a Branford MBGI020083 to measure the current over JP2.

PWR_SMPS_16MHZ_HSI with RF Stack:

3-5mA

PWR_STOP2_RTC:

~3,8uA i think...

PWR_EnterStandbyMode:

~1.3uA

BLE_HeartRate:

~200-220uA (no connection)

~3-130uA (no connection after some time - I reckon LP advertising kicks in?)

~1100uA (connected)

I'm Quite confused now, but this must mean that low power works, but measuring with the X-Nucleo-LPM01A is a bad strategy?