How to use nRF52840-DK with an external power supply?

[eye]

Hello,

Now,in my application I use to power the nRF52840 with a 3.3V external supply at the VDD pin.

I want to know how to set it, I want to power the nRF52840 with a 3.3V external supply at P21.

It does not energize in this setting.
Is there a missing or unnecessary settings?

・SB36 -> shorted
・SB39 -> shorted
・SW6 -> DEFUULT
・SW8 -> ON
・SW10 -> OFF

Best Regard.

eye

[Jared]

Hi,

How is SW9 configured?

Best regards

Jared 

[eye]

Hi,Jared

Thank you for reply

  SW9 =>VDD

Best regards

eye

[eye]

I checked additionally

 P27.Li-in connector(3.3V) 

=>  OK

I think so, It is effective only when using 5 V power sources.

eye

[Jared]

Hi,

What power source are you using when it's not working? 

eye said:

 P27.Li-in connector(3.3V) 

=>  OK

Does this mean that it worked with the Li-Po battery connected to P27?

Best regards

Jared

 

[eye]

He, Sorry for the late reply.

> What power source are you using when it's not working? 

I usually use VIN3-5V .

But , When measuring current,　　It is not recommended.



>Does this mean that it worked with the Li-Po battery connected to P27?
Yes.　
Instead of the　Li-Po　battery, P27 was powered by supplying 3.3 V from the regulated power supply.


Best regards.

eye 

[Jared]

Ok, i'm not sure I understand. It worked with the Li-Po battery connected to P27, but did not work with external supply connected to P20?

[eye]

Hi,

> It worked with the Li-Po battery connected to P27

=> Yes.It worked.

---

> did not work with external supply connected to P20?

with external supply connected to P21

=> It did not work.

---

with VIN3-5V  connected to P20

=> It worked.

---

Best Regards.

eye

[Jared]

Ok. This is probably due to the power requirements of the application. What external power source are you using on P21? A coin cell will not deliver enough for the application to run.