Custom nRF52840 module high power consumption with OPENTHREAD turned on

[zhangxka]

I have a custom nRF52840 module (made by Holyiot 18010) running the default Blinky program with some custom configs. I'm measuring its power consumption with PPK II with source mode on a 3V voltage. If I run the program normally the current consumption hovers around ~10uA (which is to be expected). However, if I have CONFIG_NET_L2_OPENTHREAD=y, the average current jumps to 1mA and stays there. 

What is strange is that when I try to run the same program with OPENTHREAD turned on for the nrf52840 DK, the current seems to be back in the uA range. Any idea what could be the problem here? Appreciate any help!

[Marte Myrvold]

Hi,

Does the module have an external 32 KHz XTAL? If not, please try enabling the RC oscillator in your prj.conf:

CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y

Best regards,
Marte

[zhangxka]

Hi Marte,

Thanks for your reply! It does look like it has an external 32 KHz XTAL. Please see the schematics of the custom module below:

[haakonsh]

Set BOARD_ENABLE_DCDC_HV=n in your prj.conf file. You also need to remove L4 and C19, and connect VDDH to VDD with a short wire. That should put the board in a good state, though there might be permanent damage to the REG0 stage. Also note that max input voltage is now 3.9V instead of 5.5V. 

BTW, was this module designed for you by HolyIOT or is this one of their off-the-shelf modules? 

[zhangxka]

Hey Håkon, unfortunately this is one of their off the shelf modules. Would source another nRF module my only other option then for a low power consumption IOT device? It seem to be a design error on the HolyIOT part and there’s no way to override their module connections 

[haakonsh]

Yes, you need to source another module. See our list of Third-party modules. I've notified HolyIOT about the issue, but I don't know if they will fix or how much time it will take. You can contact them directly and ask them yourself. They will probably fix the issue and sell you their new revision directly if they are able to.

[zhangxka]

Sounds good. Thanks for the help!

[zhangxka]

Hey Håkon, 

I have decided to use another module (E73 for now). I have attached their schematics below and modified the external circuit using sample circuit #2 as a reference. Can you help me take a look and make sure the wires/components I added make sense? 

One thing to note here is that I am not using VUSB to supply any powers. It's there to detect the presence of USB power source so that I get the charging event through USB module.

Best,

Kevin

[zhangxka]

Hey Håkon, curious if you can take a look the circuit above and see if there are any problems with it. Thanks!

[haakonsh]

Hey Kevin, sry for the late reply.

That schematic looks good. 

Alternative Pre-certified modules:

Fanstel BC840

U-Blox NINA-B301

Laird BL654

BR,
Håkon Holdhus.

[zhangxka]

Thanks a lot for the help! Really appreciate it