How to use P21 external supply in nRF52833 DK

Question

Hi, 
 I am using nRF52833 DK and power it using P21 External supply. I connected P21 with the power profiler 2 and give 1.8V. It works for serveral days, however, today I notice when I give 1.8V the program will not run. If I change to around 2.2V, it start running. 
 I have three questions: 
 1. What happen to the DK, before it can work under 1.8V, now it cannot. 
 2. When I am measure the current through P21, with all default setting(VDD power source, vEXT-nRF off, default), am I measuring the total current consume by the nrf52833 and interface MCU? 
 3.Can P21 use together with Lipo battery, if I connect a battery here, is there any battery management circuit after P21. 
 I have found some schemetic but I have no clue about what is happening in this DK. Thank you so much for your time!

Simonr · Accepted Answer

Hi 
 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

Ziyao Zhou · Answer

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

How to use P21 external supply in nRF52833 DK

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