Rak3172 low current problem

LPWAN Modules / EVBs RAK3172
#1

I am working on low level development on rak3172 breakout board. I am using Keil for development. main thing is getting data from gps and putting rak to sleep. Most of the work is completed, but I am facing this current issue.
The current of the module did not goes below 350uA. I have tried sleep mode. I have tried stop 2 mode with RTC (low power regulator on).

Stop 2: Stop mode with low power regulator and VDD12I interruptible digital core domain supply OFF (less peripherals activated than low power mode stop 1 to reduce power consumption)

Can you kindly guide me how can I achieve 2uA as claimed in datasheet.

#2

Welcome to RAK forum @bilalfakhar ,

Working on low level power management involved various things and hard to point out exactly where the the few microamps are coming from. You are pretty much in low power but the extra uA can be attributed on leakage current on IO pins, UART TX/RX, clock parameters, etc.

If you need custom firmware for RAK3172, our RAKwireless Unified Interface (RUI3) supports RAK3172. You can probably have a look. Low power management is already handled for you :slight_smile:

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#3

thank you Carlrowan for your reply. i tried rui v3 and still the current was at 350uA. out of no where i just pulled out stlink and the current came to 1.6uA. :slight_smile: it was a mistake to measure current with stlink plugged in. now the stop mode in keil mdk arm is also giving the same current (1.6uA).

thank you
Bilal

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#4

Hello,
i can confirm that leaving STLink or FTDI connected draws extra current, and once those are removed i was able to get 2.20uA in sleep mode api.system.sleep.all(10000); “Very Cool” but not the 1.6uA as mentioned, which i would contribute to the various extra resistors i have on the custom board.

cheers,
Jay.

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#5

The Vcc connection in the SWD interface to the STLink powers part of the circuitry in the STlink (sets the voltage level of the target board to the debugger, probably via level translators) and it draws current from the target. It is normal that you must disconnect at least this wire to do low current measurement of the target board.

There are other potential current paths via the UART pins if you are using those.

It is best to avoid external connections while doing low current measurements if at all possible.

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#6

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