Analyzing power consumption on nrf52840-DK with keysight N6705C

[gnrboy]

Hi can you help to configure nrf52840 DK board to measure power consumption with keysight n6705C. In manual is described with ammpermeter and oscilloscope. Keysight n6705c will also be power supply to the nf52840dk via P22 (3.6V DC). Is it enough just to cut SB40 or ? I want just to measure current of nrf52840 and with board leds.

[gnrboy]

or I must connect keysight on p21 ?

which modification ?

[Jared]

Hi,

It's enough to just cut the solder bridge, and set the Keysight to current measure mode.

regards

Jared 

[Jared]

gnrboy said:

If I want to power buttosn and leds sw6 leave to default?

 Yes, if you want to power the rest of the board then this should be default. 

[gnrboy]

gnrboy said:

Its not burn or something else because now when only  on j2 usb connected and via this connect all board have power (sw8 = ON, SW6=default, SW9 = VDD,sb40/sb41 are short (default)) ? sw10 (vext ->nrf) default off need to change to on thaht will separate powering via j2 and P21  ?

And this is ok? Is it possible to achieve this without connecting usb  J2 to power Jlink and rest of the board?

[Jared]

Hi,

gnrboy said:

Its not burn or something else because now when only  on j2 usb connected and via this connect all board have power (sw8 = ON, SW6=default, SW9 = VDD,sb40/sb41 are short (default)) ? sw10 (vext ->nrf) default off need to change to on thaht will separate powering via j2 and P21  ?

I'm not sure I understand what you're asking. Could you try to re-phrase the question? Are you asking if it's ok to supply the board with power from the USB and external power at the same time? 

Jared 

[gnrboy]

gnrboy said:

Hi, I tried now with the zigbee light switch example, and it works with the setup you described.

• Power through P21
• SW10 to ON
• SW6 to nRF only
• SW9 to VDD
• Plug in the USB cable (J2), to power the rest of the board
• SB40/SB41 closed

With that setup I'm able to measure current going in to P21 and still toggle the light with the buttons

Yea that is question because that is from article which you have sent me to read? And sw10 (vext ->nrf) default off need to change to on thaht will separate powering via j2 and P21  ?

[Jared]

Hi, 

Following the method described in the thread should not hurt the board. For more info, see our Power supply section in the documentation for the Devkit here. 

Jared