Power Profiler Kit gives wrong current measurments

[5IM00N]

Hi,

I have used the kit for weeks now measuring the power consumption of my custom hardware with the external hardware setup [1].

Suddenly the sleep currents of my target increased by factor 10 and the advertising currents reach the 80mA border. I checked the measurements by switching an ampere-meter into the circuit. The ampere-meter measures my old average values. It seems that the PPK is broken or out of calibration.

What could be wrong?

Does the PPK get damaged after accidentally short circuit the PPK?

I read about a calibration via GUI but the current PPK GUI does not allow calibration or something like that.

[1] https://infocenter.nordicsemi.com/topic/ug_ppk/UG/ppk/PPK_user_guide_PPK_on_customHW_with_nRF5xDK.html

Best regards

[Jared]

Hi,

Indeed, if you're measuring values that you can confirm is not right by using a mulitimeter then it's probably broken.

Does the PPK get damaged after accidentally short circuit the PPK?

 Could you describe a bit more in detail how this happened?

Jared

[5IM00N]

Hi Jared,

Jared said:

 Could you describe a bit more in detail how this happened?

One time I connected my DUT in reverse polarity. Maybe this caused to much current and destroyed some device on the PPK.
Is this possible? Or is there an overload protection?

5IM00N

[Jared]

Hi,

Unfortunately, this is indeed very likely that it would hurt the device. 

regards

Jared 

[5IM00N]

I just checked the measurement ranges by connecting different resistors to it.

0...70uA , I got right values

70uA...1mA  I got right values

1..70mA , I got wrong values.

I measured R4 which seems to be the shunt resistor for 1...70mA range. I measured about 60Ohms. This explains the high measurements I got.

I checked the resistor under a microscope. There I see a small little nearly to visible dark spot on the resistor. The others are okay.

Currently I dont have a new 1R8 resistor here. So I can not check it now.

I am going to update this post as soon as I replaced the resistor and checked my values.

Update

Changing R4 (1,8Ohm) fixed the issue.

@Jared, thanks for your support!

Best regards

[ArvidB]

Hello, I accidently did the same thing to my power profiler kit 2, for me it is measurements in the around uA that is not detected at all. Currents around 100mA seems right. So probably I also have a burned resisttor but I cant see anything on the board. Do any have a suggestion on where to look extra closely?