Thread LPED example's power consumption is too high

[yaoxingshan]

I downloaded the FRDM-KW41Z SDK and imported low_power_end_device example. Then test its power consumption and find that it consumes up to 10+ mA.

The manual in the SDK package only sees a description of the page related to low power consumption.

How can I reduce power consumption?

[yaoxingshan]

I found that the cause of high power consumption is the instantiation of the Thread network. But will it not enter deep sleep after successfully joining the network?

[Alexandru-Lilia]

Hello yaoxingshan‌,

Can you tell me what SDK version are you using?

Also, if you happen to have a sniffer, it would help me debug the problem a capture with the LPED joining the network.

Regards,

Lilian

[yaoxingshan]

Hello Lilian,

I am using two examples in the 2.2.0 SDK, REED and LPED.

When LPED is powered on for the first time, the REED shell will prompt “Joiner accepted”, and when I debug it, it will enter PWR_HandleSleep() after entering the network.

I guess it has entered the Sleep Mode and the wireless transceiver is turned off, but the MCU has not entered the low power mode.

I saw that there are only dedicated modes for BLE and ZIGBEE in the PWR module, but there is no THREAD. So I would like to ask, THREAD's LPED power consumption can only be reduced to about 5mA? If not, please help me modify the example to reduce its power consumption.

Thank you,
Lilian

[Alexandru-Lilia · Accepted solution]

Hi there,

Unfortunately there is a problem with the SDK, it has been fixed but it won't be available until 31th of July.

Let me try to find an workaround to this. I'll come back here with updates.

Best regards,

Lilian

[yaoxingshan]

Today is July 31, but I haven't seen the new SDK released on the official website.

[Alexandru-Lilia]

Hello,

Sorry for the inconvenience. The product is ready, but has not been publicly released yet due to some more reviews and verification that needed to be done. Stay tuned.

If you want, I can reply on this thread when it will be ready.

Best regards,

Lilian

[yaoxingshan]

Hello,

I updated the new SDK (2018-08-16) and imported a low-power example and found that its power consumption is still as high as 4.0mA.

Is the problem not fixed? Or need to do some related processing?

looking forward to your reply
Thank you

[Alexandru-Lilia]

Hello,

I've just downloaded the current SDK and it seems that LPED functions normally. The current value I've measured was ~2 uA.

A few observations:

• make sure that the LPED is connected to the network, else it will continuously search for a network to join, which will consume a considerably amount of power
• how do you do the measurement? Based on this schematic, I measure on J22, 1-3 pins.

Please take into consideration the observations, an tell me if the problem persists.

All the best,

Lilian

[yaoxingshan]

Hello,
I will jump the cap into the following mode.

Then use a meter to measure the position of the image below：

When I press the button to join the network, the meter shows a power consumption of about 15mA.
Then I can see that the router's shell shows that it has agreed to join.

Finally, the meter showed that its power consumption dropped to about 4mA.

[Alexandru-Lilia]

Hello,

I've tried to do the measurement in buck-mode as you did and I came across some problems:

• the board was always resetting if I had the multimeter connected as shown in the image; I don't know why it does, probably the internal resistance was not suitable for such measurement; when I used uA scale it didn't work, but when I used mA scale it worked, but I don't know how precise the measurement was; 
• when in buck-mode, you should define gDCDC_Enabled_d to 1, in config.h;
• if you are using revision A3, on the back of the board is a shunt resistor, SH503, which powers the LEDs, which consumes a considerable amount of power; scratch it with a cutter, and don't worry, you can remake the connection with a little bit of solder;

This is a measurement with a very high precision multimeter, in buck-mode, as in the picture you attached:

As you can see, the average is 3.364 uA.

Regarding the measurement in bypass mode as I've explained to you, it probably is that high because something on the board has broken. It happened to me too on a board after I changed the jumpers while being connected to the power source. At least that's what I think.

Good luck.

Regards,

Lilian

[yaoxingshan]

Hello，

I tried to change the working mode to what you said.

Then, it show a power consumption of about 120uA.

How can I reduce its power consumption to 2uA?

[phantomgz]

It's very  surprise, before release this SDK, is it some one test this most basic using scene?

[Alexandru-Lilia]

I don't know if this is what you were looking for, but check chapters 9, 10 and 11 from *sdk_folder*/docs/wireless/Thread/Kinetis Thread Stack Demo Applications User's Guide.pdf.

Regards,

Lilian

[yaoxingshan]

Hello there,

I still have a problem: the development documentation carried in the SDK describes too little content. Will the follow-up update add more content?

Thank you,
Lilian

[Alexandru-Lilia]

Hello,

I don't think there will be anything added to the documentation because there will not be any significant changes in the SDK, but feel free to use the community forum.

You can first check it to see if somebody else had the same question and if you don't find what you were looking for you can add a new question.

Regards,

Lilian