High power consumption on nRF5340 custom board

[Michael Crevier]

Hi,

I run a couple test with the PPK2 on our board to measure and optimize the power consumption, but I had some weird results and I'm hopping you can help me out to understand the behavior. Our custom board is a BC40C module from Fanstel (nRF5340 with the DC/DC and crystals components), and a WM02C From Fanstel (nRF7002), with a flash memory and an IMU.

So to sum things up, I have a debut build with uart0 and logs enabled, and a production build with uart0 and log disabled, plus that overlay:

CONFIG_SERIAL=y
CONFIG_UART_NRFX=y
CONFIG_LOG=n
CONFIG_PRINTK=n
CONFIG_CONSOLE=n
CONFIG_EARLY_CONSOLE=n
CONFIG_CONSOLE_SUBSYS=n
CONFIG_UART_CONSOLE=n
CONFIG_BOOT_BANNER=n
CONFIG_PM_DEVICE=y
CONFIG_PM_DEVICE_RUNTIME=y
CONFIG_NRF_WIFI_LOW_POWER=y
CONFIG_INIT_STACKS=n
CONFIG_NRF_APPROTECT_LOCK=n
CONFIG_BOARD_ENABLE_DCDC_APP=y
CONFIG_BOARD_ENABLE_DCDC_NET=y
CONFIG_BOARD_ENABLE_DCDC_HV=y

However, I have a lower power consumption wih the debug build then with the prod build. Furthermore, when I put the device into power off (with sys_poweroff()), I have a quite high power consumption too, see images below.

Debug build

Prod build

System Off (prod build)

I followed the recommandation in the documentations and the blog post here, but I still have those results, and I'm currently running out of ideas...

Any solutions? I'm joining the dts and .config files from each build here if you want to take a look, but they are pretty much the same except the differences for the logs.

Thanks,

Michael

2806.files.zip

[Kenneth]

I would start by investigating the system OFF current.

System Off (prod build)

This shouldn't really be possible. Is the supply rail you are measuring on here only going to the nRF5340, or does it also include the flash memory and IMU? 

Possible check if you may be sourcing some current through pins also.

Edit: Also check out in general:
https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/test_and_optimize/optimizing/power.html 

It might be a good idea to try to narrow down the functionality in the app a bit and see if any specific modules seems to cause the increased current consumption.

Kenneth

[Michael Crevier]

Hi Kenneth,

The measurement include the whole board, so nRF5340, nRf7002, mx25r64 FLASH and IMU.

I already took a look at that documentation, but I will make sure everything is well applied and do some more measurement to share the results with you.

Thanks,

Micahel

[Kenneth]

Sounds good, I cant seem to find CONFIG_PM enabled anywhere, I would expect that is needed also.

Kenneth