ppk gives wrong value.

[madblue]

Hi,

I am using ppk with nrf52832 dk to measure the current consumption of my board and it giving different values at different times. for two days it gave 250uA and tested it with 5/6 different boards and all were in same range. but after 4 days when try again, with same sw and hw without any change, it gives 34-40 mA.

My connections,

DUT Switch : external

power supply switch : reg  (at 3.6 V)

COM switch : dk

nrf ppk sw 2.6.1 and 2.5 on ubuntu and windows.

I have connected a 10k and 100k resistors as load and measured the consumption and it was giving correct value.

I have tested the power consumption of all these same boards  with gold uCurrent  and it gives the values as 800uA consistently across all the devices.

How can i make sure that my ppk is working fine? what are all the ways to trouble-shoot ppk ?

[Stian Røed Hafskjold]

When using PPK on top of the DK there are some issues with using the onboard regulator; power select switch in Reg position. Can you try again with the switch in the DK position?

[madblue]

Hi Stian,

Thank you for the update,

I have already tried with an external supply from a battery by changing the switch to external, but there is not much variations. it is showing around 30mA.

Also one more thing i have noticed, as the vdd decrease from 3.6 the power consumption also decreases slightly (around 5mA).

when i select dk, it shows constant 80 mA consumption. also tried to read the power consumption from dk but that was inconsistent. it was varying from -3 mA to 3 mA.

[Stian Røed Hafskjold]

Yes, so in my previous answer I meant setting the switch to the DK position, not external, or reg position. The problem arises when using a different voltage than the DK. It has to match exactly, otherwise the current will vary with the voltage. So by switching it to the DK position you ensure that the voltage is correct.

If you get 80mA in the DK position I'm afraid that your PPK is broken, or you have a sort circuit somewhere. 80mA is the highest current the PPK will display.

[madblue]

In the user manual for ppk, it says either to use onboard regulator or external supply as power source while measuring from an external device.

Was your previous answer for measuring the power consumption of an external board?

[Stian Røed Hafskjold]

Sorry for the confusion. Yes, I was talking about using it for an external device. I was not aware that the user guide said to either use external or internal reg. However I've seen issues with this setup before, so I think you should try setting it in the DK position.

Anyways, a value of 30-80mA I think indicates a broken PPK.