Current measurements NRF9160 DK

RE: Current measurements NRF9160 DK

Marjeris Romero — Tue, 17 Mar 2020 09:57:57 GMT

Hi,

P15 is used for the current measurements using the PPK. The firsts pins are the same as the ones in P24 and the rest are SWD.

[quote user="isurki"]Do you refer to SW1 ("nRF only" switch)? It seems that SW6 is for testing digital inputs.[/quote]

Yes, it seems the switch's name was changed to SW1 in some later versions of the DK. See "IFMCU DISCONN" switch in the hardware figures here.

[quote user="isurki"]The aim is to achieve low power consumption of all DK, not for the nRF91 only.[/quote]

You can take a look at the DK schematics to see if there is something you can do. You can download the hardware files from the nRF9160 DK product page. But keep in mind we don't recommend using the nRF91 DK as a finished design.

You could instead measure the current on a Thingy:91, which is better suited to be used as a reference design.

Best regards,

Marjeris

RE: Current measurements NRF9160 DK

isurki — Tue, 10 Mar 2020 12:51:01 GMT

Hi;

[quote userid="73427" url="~/f/nordic-q-a/58764/current-measurements-nrf9160-dk/239084"]I am not sure if you can power only the nRF91 chip when using P28[/quote]

And is it possible to only power the nRF91 chip using P15 pins?

[quote userid="73427" url="~/f/nordic-q-a/58764/current-measurements-nrf9160-dk/239084"]here is a switch for disconnecting the interface MCU (SW6)[/quote]

Do you refer to SW1 ("nRF only" switch)? It seems that SW6 is for testing digital inputs.

Can we achieve a lower power consumption disconnecting a solder bridge(SB13 for LDO for example)?

The aim is to achieve low power consumption of all DK, not for the nRF91 only.

Thanks for you help,

Kind regards.

RE: Current measurements NRF9160 DK

Marjeris Romero — Tue, 10 Mar 2020 11:48:51 GMT

Hi,

The negative values at the start of a measurement are common if you have inductive/capacitive load, the important thing is the average current you measure when it's stabilized.

I am not sure if you can power only the nRF91 chip when using P28. There is a switch for disconnecting the interface MCU (SW6) but you still will be powering the rest of the board, so for accurate measurements I recommend measuring using header P24 as described in the documentation. Take a look at this blogpost for more information.

BR,

Marjeris

RE: Current measurements NRF9160 DK

isurki — Fri, 06 Mar 2020 17:40:29 GMT

Hi;

Thanks for your answer!

1.-I get negative current values from 60 to 25uA until it stabilizes at +4uA after 3 seconds approximately.

2.-I am connecting the Li-Ion battery to the P28 connector. How can I power the board to avoid Segger programmer chip and everything else extra consumption? I only want to power the NRF9160.

Kind regards.

RE: Current measurements NRF9160 DK

Marjeris Romero — Fri, 06 Mar 2020 13:44:03 GMT

Hi,

1. How much negative current are you measuring and how long does it take to stabilize at 4 uA. Some negative current during peak time can be expected because of the circuits capacitance.

2. How are you connecting the Li-Ion battery? If you connect the battery to the external supply header you will measure the current going into the Segger programmer chip and everything else in the DK.Current measurement from the current measurement header P24 shows only the current that is used by the nRF91 chip.

BR,

Marjeris