STM32L412 LPUART with ST232

[DBhut.1]

Hello,

STM32L412 will be in stop mode 2 with LPUART. This device is a slave device, master device wakeup on time schedule and gather data from it by RS232.

ST232 is powered by master device.

But issue is that when ST232 power is off by master, then it takes current from slave device(slaves's RX,TX and GND is only connected with ST232), which causes 2-3mA of current consumption.

So, please help us, how we can reduce this current consumption, we want to acheive current consumption of max 5uA in stop mode 2 from slave device.

Thank You

[Imen.D]

Hello @DBhut.1​,

Please have a look at this Application note, it may help you:

• AN4635 Application note Minimization of power consumption using LPUART for STM32 microcontrollers.

If you are satisfied of my answer, please mark it as "Best", so that this thread will be marked as solved.

Imen

[DBhut.1]

Thanks for reply, but it doesn't solve my problem. I have already gone through it.

Below is block diagram of my application.

Here Master device will control the power of ST232 of slave device.

Issue is when master off the vcc power of ST232, Current consumption from slave side is increased to 2mA, may be due to RX TX pin of LPUART of STM32.

So, Please Suggest best to solve this issue.

Thank You