High power consumption on nrf5340 custom board bluetooth mesh

RE: High power consumption on nrf5340 custom board bluetooth mesh

Simonr — Mon, 15 Jan 2024 08:26:03 GMT

That would make sense, to me at least, because the VDD/VDDH pin won't be affected when in system off, so please make sure the VDDH pin is connected correctly and see if the issue still persists or not. Then we can entertain the thought of this being a SW issue.

Best regards,

Simon

RE: High power consumption on nrf5340 custom board bluetooth mesh

teover — Thu, 11 Jan 2024 15:41:35 GMT

Hi Simon!

Ok thanks, I will investigate if VDDH pin not being connected is causing this problem.

To clarify, I have confirmed that the board has an acceptable power consumption when using system_off sample from nRF connect sdk and using PM_STATE_SOFT_OFF or PM_STATE_SUSPEND_TO_DISK. This measures 3 µA consumption for the MCU only and 100 µA when measuring the full board from battery, which is ok for this application.

This makes me suspect that it is a software configuration issue and not hardware issue, however I am not 100% able to confirm this.

RE: High power consumption on nrf5340 custom board bluetooth mesh

Simonr — Thu, 11 Jan 2024 13:48:06 GMT

Hi Tor Egil

If the VDDH pin is not connected to VDD on a board that is not set up to run on the high voltage mode, that will be an invalid/illegal configuration and that could very well be why the current consumption is not as expected. Based on your description it sounds like you should use Circuit configuration no. 3 from the product specification as reference in your case, so please double and triple check that you don't have any major deviations from it in your schematics.

Best regards,

Simon

RE: High power consumption on nrf5340 custom board bluetooth mesh

teover — Wed, 10 Jan 2024 14:01:35 GMT

As the board is part of a commercial system under development, I am unable to share the schematic, however I will try to explain as best I can.

The board does have additional components that draw current, however the measurements above were done on the MCU directly, with the PPK2 configured as ampere meter measuring current through VDD_nRF.
As mentioned, it is a BT40 from Fanstel, so no external crystals.
The internal DCDC is not in use, and I see no difference with CONFIG_BOARD_ENABLE_DCDC_[APP, NET, HV] is set to y/n

I noticed however that VDDH is not connected to VDD as specified in https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf5340%2Fchapters%2Fsupply%2Fdoc%2Fpower_supply.html

RE: High power consumption on nrf5340 custom board bluetooth mesh

Simonr — Wed, 10 Jan 2024 10:12:49 GMT

Since the difference in current is so big on the custom board vs. the DK, my guess is that the custom board has some detrimental differences in HW compared to the DK, for example poorly loaded external crystals or the lack of DCDC components while still trying to use the DCDC regulator in the application or similar.

Could you upload the schematics of your custom board so we could take a closer look and compare it with the DK files? Also, does the custom board perhaps have some other components on the board that might draw additional current? Other SoCs, chips, etc. Can you also show us how exactly you measure current on the custom board with a picture for instance.

Best regards,

Simon