NRF5340DK Power consumption while in HV Mode

[pauleffect]

Hello.

Im using a 5340DK to measure its current consumption while in HV mode.

NCS version is 2.4.1   The .conf file below.

The board is supplied via VDD_BAT and there are two external components (2), supplied from the VDD pin of the board (accurately measured while the firmware is running). 

# RTOS
CONFIG_MAIN_STACK_SIZE=4096
CONFIG_HEAP_MEM_POOL_SIZE=4096
CONFIG_EVENTS=y

# POWER MANAGEMENT
CONFIG_ADC=y
CONFIG_ADC_NRFX_SAADC=y
CONFIG_NRFX_SAADC=y
CONFIG_PM=y
CONFIG_PM_DEVICE=y
CONFIG_NRFX_POWER=y
CONFIG_BOARD_ENABLE_DCDC_APP=y
CONFIG_BOARD_ENABLE_DCDC_NET=y
CONFIG_BOARD_ENABLE_DCDC_HV=y

# SECURITY
CONFIG_NRF_SECURITY=y
CONFIG_MBEDTLS_PSA_CRYPTO_C=y
CONFIG_MBEDTLS_ENABLE_HEAP=y
CONFIG_MBEDTLS_HEAP_SIZE=8192
CONFIG_MPU_ALLOW_FLASH_WRITE=y
CONFIG_FPU=y

# MESSAGING
CONFIG_IPC_SERVICE=y
CONFIG_IPC_SERVICE_LOG_LEVEL_INF=n
CONFIG_IPC_SERVICE_BACKEND_ICMSG=y
CONFIG_IPC_SERVICE_BACKEND_RPMSG=n
CONFIG_MBOX=y

# NAND
CONFIG_SPI=y
CONFIG_SPI_ASYNC=y

# AUDIO
CONFIG_I2S=y
CONFIG_I2C=y
CONFIG_NRFX_I2S=y


CONFIG_BOARD_ENABLE_CPUNET=y

Im using SAADC, I2C, I2S (nrfx drivers), UART, SPI. The NET firmware sits idle. The idle power consumption of the board sits comfortably down in the uA range.

UART state is toggled in firmware, being enabled on demand when a line should be sent to pc.

I2C only enabled when needed.

SAADC is used for vddh voltage measurement @ 1hz frequency.

I2S is used in master mode @32Khz, 16bit, mono. The MCLK pin divisor is bypassed (12.288 Mhz output). Tx pin disabled.

SPI is only enabled when needed (roughly twice / minute, for ~ 300 ms).

---

With the device doing active work, the power consumption of the board is ~5mA when nothing is connected to the usb port of the nrf (1) and ~ 3.2 mA when I plug a usb cable into the aforementioned port. I supplied power via the USB port because I read here, on this forum (can't find the link), that some components on the dev kit would still need power (the switches, passives etc), so the board should still be supplied with power, not just the MCU part.

By active I mean I2S + external codec running.

Judging from the peripherals I use + the external components in use (which I have accurately measured with tools way more expensive than my car), I should be looking at a power consumption of less than 2.5 mA, mostly coming from the i2s peripheral.

Is the first measured figure (basically with the board only powered by VDD_BAT), 5mAm, correct or is it time to pop a champagne? 

EDIT: Clarifications added.

[JONATHAN LL]

Hi,

We do have a guide here : https://infocenter.nordicsemi.com/topic/ug_nrf5340_dk/UG/dk/hw_measure_current.html?cp=4_0_4_5  on how to measure current on the DK. 

And we also have an introduction that does describe general proscess. https://devzone.nordicsemi.com/guides/hardware-design-test-and-measuring/b/nrf5x/posts/current-measurement-guide-introduction 
 

So you can measure on the current measurement port for either HV(P23) or normal mode (P22).  There is a solder bridge for each SB40 and SB41. 


With a PPKII or a power analyzer you should relatively easily be able to se what is drawing current and when. 

Regards,
Jonathan

[pauleffect]

Thank you for the generic answer. I asked a specific question though. I did read the docs, would you also be so kind as to read my question?
I did measure the current and ended up with two different measurements, depending on the setup.

[JONATHAN LL]

Are you measuring the current on P22 or P23 ? or are you measuring the current thorough the USB? 

To get an accurate representation on what the nRF would draw then you should measure on one of the two measurements connectors. 

Is the radio in use? 

The numbers you show to seems realistic but know way for me to confirm so its educated guessing. Since the number is sleep is from your description correct then the idle values you show to is realistic. As to why exactly the current drops to 3.2mA when connected with USB could be many reason but without the code I cant say anything to why. It is a very likely situation. 

You can check out some of the numbers here https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/current_consumption/doc/current_consumption.html?cp=4_0_0_3_3_0_1#unique_1344442403, and for the app to just idle\run somewhere around 3.2-3.6mA is normal. 


So it looks ok. 

Regards,
Jonathan

[pauleffect]

Are you measuring the current on P22 or P23 ? or are you measuring the current thorough the USB? 
Im measuring the current using a source meter, directly on the lipo. net core idle. As stated.

im asking why the current drops from 5V to 3.2 when connecting the MCU to an usb port 

The difference is huge. And it has nothing to do with the app code.

i mean, its a 2ma difference. 

[JONATHAN LL]

Pleas measure on the P22 or P23 measurement pins for correct results. 

What could be happening now is that the peripherals(Debugger\led\switches) on the DK stops being powered from the battery that your are measuring on and is being powered from the USB, if your are using the J2 USB connector. 

Regards,
Jonathan

[pauleffect]

Thats what i was hoping for. But the leds are not powered and neither is the debugger. Isnt that the whole point of the nrf only switch?

[JONATHAN LL]

What USB connector are you using? 

And what position is SW9 in? (USB\VDD\Li-po)

Can you share the hex file so that I can try and reproduce the issue?

What version of the nRF5340DK do you have?

You don't need to flip SW6 to nRF ONLY to measure current used by the nRF. 

Regards,
Joanthan