How to use P21 external supply in nRF52833 DK

RE: How to use P21 external supply in nRF52833 DK

Simonr — Tue, 18 Mar 2025 13:12:28 GMT

As explained, the P21 supply must be supplied with between 2.5 and 5.5V. The voltage follower circuit is there to make sure there aren't any mismatches betweent he external supply and the USB supply. Yes, the PPK2 can be used as a supply on P21, but this isn't its intention. If so, the DK should also be set in the nRF Only mode to prevent leakage currents due to voltage differences on the board (this is SW6 on the DK).

Best regards,

Simon

RE: How to use P21 external supply in nRF52833 DK

Ziyao Zhou — Tue, 18 Mar 2025 12:24:37 GMT

Thank you for your reply! Does that mean I cannot use PPK to be the external supply in P21, I just want to use it as a stable voltage source.

By the way, what is the voltage follower? Does that mean the P21 must have a voltage higher than 5V?

RE: How to use P21 external supply in nRF52833 DK

Simonr — Tue, 18 Mar 2025 10:31:10 GMT

From the nRF52833 DK

"To avoid voltage differences on the DK, the external supply is also connected to the input of the voltage follower when the VEXT->nRF switch (SW10) is in the ON position. The voltage follower circuit requires 5 V supplied to the DK. The voltage follower can be disconnected from the External supply by cutting SB58. To prevent leakage due to voltage differences, the DK should be set in the nRF only mode."

So if you're measuring current while powering the board from P21 with SW10 set, the PPK2 should not be used as a Sourcemeter, but rather an Amperemeter since it already has an external supply in this mode. I think you're seeing a lot of leakage having multiple power sources here.

Best regards,

Simon

RE: How to use P21 external supply in nRF52833 DK

Ziyao Zhou — Mon, 17 Mar 2025 11:28:14 GMT

I just try to use a brand new nRF52833 DK, I notice when I switch SW10 to the ON position and SW9 to the middle position (VDD) the program (system off and will be trigger wakeup through buttons) will not work correctly, only when SW10 to the off it works well. Why this happen to a brandnew DK?

1. SW10 off works well.

1. SW10 on high power consumption.

I am very sure when I switch on the power gose higher, this is on the opposite of

[quote userid="75734" url="~/f/nordic-q-a/119551/how-to-use-p21-external-supply-in-nrf52833-dk/526006"]

1. To power the nRF52833 from P21, you should slide the switch SW10 to the ON position and SW9 to the middle position (VDD).

[/quote]

RE: How to use P21 external supply in nRF52833 DK

Simonr — Mon, 17 Mar 2025 08:34:12 GMT

Can you share some details on what SW9 is set to with these measurements. I'm not so sure the boards is damaged (unless you've powered it above the specified values. But I see here that you're powering it with 1.8V, which will only be supported if you power the board with SW9 in the VDD position. The Li-Po and USB settings only support 2.5V-5.5V supply voltages. That being said. Please also make sure you have the micro USB connected to the debugger MCU so that it is powered as well. If not you'll also see a lot of noise.

Best regards,

Simon

RE: How to use P21 external supply in nRF52833 DK

Ziyao Zhou — Sat, 15 Mar 2025 12:02:25 GMT

I am running one program,when I put SW10 VEXT->nRF off the power consumtion is

When I put SW10 VEXT->nRF on the power is

I guess it's because I have use the port wrongly and damaged the circuit

[quote userid="137325" url="~/f/nordic-q-a/119551/how-to-use-p21-external-supply-in-nrf52833-dk"]

3.Can P21 use together with Lipo battery, if I connect a battery here, is there any battery management circuit after P21.

[/quote]

RE: How to use P21 external supply in nRF52833 DK

Sigurd Hellesvik — Wed, 12 Mar 2025 14:37:39 GMT

Hi Zhou,

It looks like Simons previous answer both covers SW10 and SW9.

Do you still have any open questions?

Regards,
Sigurd Hellesvik

RE: How to use P21 external supply in nRF52833 DK

Ziyao Zhou — Sat, 08 Mar 2025 01:20:00 GMT

I am saying SW10 VEXT

RE: How to use P21 external supply in nRF52833 DK

Simonr — Fri, 07 Mar 2025 11:30:14 GMT

Do you mean SW10 VEXT->nRF or SW9 (Li-Po, VDD, USB). Switching SW10 should not affect the nRF as long as you have powered the device from an external supply. SW9 switches which power source is used. Between Li-Po, VDD and USB.

Best regards,

Simon

RE: How to use P21 external supply in nRF52833 DK

Ziyao Zhou — Thu, 06 Mar 2025 11:35:04 GMT

Thank you for your reply! I am using BLE and when I switch SW9 to ON I will notice it stop working. Only when I swithch off it works, it is really strange.

RE: How to use P21 external supply in nRF52833 DK

Simonr — Thu, 06 Mar 2025 11:28:03 GMT

1. Switching SW9 will only power the nRF52833, so I think your code still runs, but the interface MCU and thus logging will no longer be printed onto the computer, nor will any LEDs blink, if that's how you determine if the application is running or not. I.E. the radio should still run with SW9 set to ON.

2. Yes, this will power more than just the nRF52833, and you will see inaccurate current consumption numbers as it also powers the LEDs, etc. of th eDK. P22 will only power the nRF52833 DK, while you can plug in a USB cable to J3 to power the rest of the DK and get accurate current consumption numbers while I.E. doing logging.

3. You should follow the DK user guide, as we can't provide any guarantees if you don't. Powering P21 with a battery most likely will work and not damage the DK, but we can't guarantee that it won't as this is not something we've done extensive testing on on our end.

Best regards,

Simon

RE: How to use P21 external supply in nRF52833 DK

Ziyao Zhou — Wed, 05 Mar 2025 15:25:06 GMT

Hi, thank you for your reply!

[quote userid="75734" url="~/f/nordic-q-a/119551/how-to-use-p21-external-supply-in-nrf52833-dk/526006"]

1. To power the nRF52833 from P21, you should slide the switch SW10 to the ON position and SW9 to the middle position (VDD).

[/quote]

I notice when I switch SW9 tp ON, my code will not run, only when I put the thing default, my code will run.

[quote userid="75734" url="~/f/nordic-q-a/119551/how-to-use-p21-external-supply-in-nrf52833-dk/526006"]

2. This will only power the nRF52833 SoC, but please note that this is not the recommended way to measure current consumption. See section 5 of the DK user guide for information on how to do that. https://docs.nordicsemi.com/bundle/ug_nrf52833_dk/page/UG/dk/intro.html

[/quote]

What is the problem if I use the default setting (VDD power source, vEXT-nRF off) setting to power, will I have some noise or what.

[quote userid="75734" url="~/f/nordic-q-a/119551/how-to-use-p21-external-supply-in-nrf52833-dk/526006"]

3. There is a separate connector for Li-Poly batteries on the nRF52833. This is the J6 or P27 that is designed for a Li-Poly battery source at 2.5-5V. If you're using it the SW9 pin should be set to the leftmost position (Li-Po).

[/quote]

I have accidently connect one battery in P21 and it works stably for a long peroiod. I want to know whether it will damage the DK if I keep using it

RE: How to use P21 external supply in nRF52833 DK

Simonr — Wed, 05 Mar 2025 14:11:09 GMT

1. To power the nRF52833 from P21, you should slide the switch SW10 to the ON position and SW9 to the middle position (VDD).

Best regards,

Simon