RE: nRF9160 DK v0.8.2 current measurement & external supply

Martin Lesund — Fri, 21 Jun 2019 13:34:50 GMT

Hi wne,

Have you tested your ammeter with something else that you can confirm it works correctly?

Please share a photo of your setup.

What application are you running on the DK?

(for external supply you should not need to do anything other than what is posted in the thread)

You should only need to follow what Bjørn suggests:

You will need to cut the SB44 on the nRF91DK. This will disable switch U25 & therefore it does not matter which position SW10 is in.

"Measuring current using the DK guide setup will give bad results. The switch (U25) leaks current from VOUT to GND even when off.

Pin closest to USB connector is pin3
1. Measure current using an ammeter: Connect to pins 1 and 2
2. Measure current using a supply like Agilent 6705: Connect to pins 1 and 3.
3. Accidentally shorting pins 2 and 3 -> dead DK! So be careful, remove USB power before connecting your measurement probes.

To make the board work again using USB power only, short pins 1 and 2."

Summary:

Flash the secure boot & the app to the nRF91 via usb, remove the usb cable, then cut the SB44 & power the board via a PSU on connector P24. SW10 can be in either position (it makes no difference when SB44 is cut). To restore normal kit operations (e.g. erasing & programming the SiP), put a jumper on the two uppermost pins of P24.

RE: nRF9160 DK v0.8.2 current measurement & external supply

wne — Fri, 21 Jun 2019 12:00:48 GMT

Hi Martin,

the problem with your linked references is, that they are not suitable with the v0.8.2 nRF9160 DK.

For example, the SB43 is cut by default on my board.

Best regards.

RE: nRF9160 DK v0.8.2 current measurement & external supply

Martin Lesund — Fri, 21 Jun 2019 11:33:37 GMT

Hi wne,

Please follow the documentation on how to measure current on the nRF91DK.
You can also take a look at this guide for a more practical approach.