RAK3172 Module Sleep Mode Current Issue

LPWAN Modules / EVBs RAK3172
1

Hi,
I started to work with RAK3172 with low level development using STM32 Cube IDE. I am using PingPong application. Module is consuming 1.2 mA in sleep mode. In the code it is specified that if no task is present it will go to Stop mode and should consume 1.5uA. But it is consuming 1.2mA.

I put all the GPIOs(except those used like RF CTRL pins and UART2 pins) in input mode for power conservation.

Current Consumption:

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image1632×758 47.6 KB

Any suggestions on reducing the sleep current?

2

Hi @Steve1 ,

The current consumption on our datasheet of less than 2uA is based on RUI3 firmware.

However, if there are external hardware connected to RAK3172 like debugger tool, external peripherals, etc. That 1mA might be coming from there.

3

Hi @carlrowan,
Thanks for the reply.
The reason for high current consumption is “Radio not going to sleep”. I have rectified it but it is still consuming 370uA. I have unplugged all the external peripherals. I have put all the GPIOs as analog inputs.
I have used the RUI3 firmware but not able to integrate DS18B20 sensor in RUI3 firmware. Is there any library from DS18B20 sensor to work with RUI3 firmware?

4

Hi @Steve1 ,

The Onewire library for the DS18B20 will be supported on the next RUI3 firmware release - 4.0.0. This is scheduled to be released this month :+1:

5

Thank you @carlrowan.

6

Hi @carlrowan,

With RUI3 RAK3172 module is consuming 4.3uA current in sleep mode. What can be done to reduce it to 2uA?

7

Hi @Steve1 ,

2uA difference is very little. Maybe it is coming somewhere?

Few questions I have:

  1. What is your VDD level on RAK3172?
  2. How do you measure the current (will you be able to share the graph of current consumption)?
  3. Are there external hardware connected to RAK3172 (is it a custom board)?
8
  1. What is your VDD level on RAK3172?
    A. VDD Level = 3.6V
  2. How do you measure the current (will you be able to share the graph of current consumption)?
    A. Using nRF Power Profiler Kit 2
  3. Are there external hardware connected to RAK3172 (is it a custom board)?
    A. Only a 2 Decoupling Capacitors and reset circuit as shown in the reference design.
9

@carlrowan

  1. What is your VDD level on RAK3172?
    A. VDD Level = 3.6V
  2. How do you measure the current (will you be able to share the graph of current consumption)?
    A. Using nRF Power Profiler Kit 2
  3. Are there external hardware connected to RAK3172 (is it a custom board)?
    A. Only a 2 Decoupling Capacitors and reset circuit as shown in the reference design.
10

Hi @Steve1 ,

Does lowering the supply level to 3.3v doesn’t bring down the current around 2uA?

Tool used and capacitors are ok.