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How to get stable current consumption in sleep?

Associate II

We are using STM32WB55RE in our application. we are trying to achieve ~10uA current consumption in sleep. But, 22uA(stable for 10min) immediately after entering sleep. After 10min current consumption start decreasing eventually to 14uA in next 60min. Why the current consumption start decreasing after 10min and how to achieve minimum stable current consumption immediately after entering sleep?

ST Employee

Hello @vpaka.1​ and welcome to the Community 🙂,

I advise you to start with PWR_LPSLEEP example with a P-NUCLEO-WB55.Nucleo board and check if you have the same issue.


To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

ST Employee

Hello Vanaja

I see your question here has been recieved and forwarded to ST Online Support. You are in direct support of our FAE engineers. You will be reached directly should any further progress be made on your case. I hope you have a great rest of your week.

Kind Regards


STMicro Support


I compared my application with PWR_LPSLEEP example code and saw 3 main differences:

1) we are using 4MHz MSI instead 2MHz. I tried with 2MHz and observed 2uA more sleep current consumption.

2) configuring flash in power down.(doesn't make any difference)

3) we are using PWR_MAINREGULATOR_ON in our application. I tried with PWR_LOWPOWERREGULATOR_ON and observed ~20uA more sleep current consumption.

we tried above 3 settings together and observed ~42uA(with 4MHz MSI, no flash power,PWR_MAINREGULATOR_ON sleep current is ~21uA).

One more thing is, with the above 3 settings also we still have the eventual drop in sleep current consumption after 10min. Which module/system could give this behavior. we are curious to know about this.




Is there any ST BLE example with LP sleep/ low power mode? Or share the best way to keep the CPU2(once it/BLE stack is started) in low power mode from CPU1. Don't need to keep the RF/CPU2 active during sleep because all the sleep wake up conditions are from CPU1.