NRF5340DK Power consumption while in HV Mode

RE: NRF5340DK Power consumption while in HV Mode

pauleffect — Fri, 13 Oct 2023 15:23:09 GMT

I'm sorry, sir. I think I understand your confusion now. The first thing in my question is a picture of a DK. With every switch labeled with the position they're in. Clearly, you didn't see that. Probably some forum error. Anyway:

SW9: LIPO.

SW10: ON

SW8: ON

SW6: NRF ONLY.

J3 connected to a pc: ~ 3mA. J3 left disconnected: 5mA. The exact same piece of code.

The thing is, the 3.2 power consumption is what I estimated from the docs (and adding the obvious FUBAR coefficients, laws of murphy be observed). The 5mA figure is ridiculous though. I'm just trying to be as sure as humanly possible that the design is ok before proceeding, as I'm sure you understand.

EDIT: Just to be clear, I dont want to measure the MCU power consumption. I want to measure the power consumption of the MCU + the two external components while powered via NRF's VDD. Because the efficiency of the DC-DC isn't quite well documented (or I haven't been able to find info, on the forum or otherwise). I'm interested in profiling it, so I will make the decision to either include a PMIC (probaby nPM 1300) or run the MCU in HV mode directly. I would gladly accept, for example, a 500 uA hit in run mode, if that meant less components on the board.

RE: NRF5340DK Power consumption while in HV Mode

JONATHAN LL — Fri, 13 Oct 2023 15:11:18 GMT

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

RE: NRF5340DK Power consumption while in HV Mode

pauleffect — Fri, 13 Oct 2023 14:56:16 GMT

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?

RE: NRF5340DK Power consumption while in HV Mode

JONATHAN LL — Fri, 13 Oct 2023 14:53:28 GMT

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

RE: NRF5340DK Power consumption while in HV Mode

pauleffect — Fri, 13 Oct 2023 14:39:37 GMT

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.

RE: NRF5340DK Power consumption while in HV Mode

JONATHAN LL — Fri, 13 Oct 2023 14:29:13 GMT

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

RE: NRF5340DK Power consumption while in HV Mode

pauleffect — Fri, 13 Oct 2023 12:13:14 GMT

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.

RE: NRF5340DK Power consumption while in HV Mode

JONATHAN LL — Fri, 13 Oct 2023 11:01:44 GMT

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