power profile kit ii amp meter mode

[szhaulai]

Hi 

I have a question need someone to clarify. 

Why is the ampere meter mode has a enable power out slide bar? Isn't the amp meter suppose to be off all the time so that all power is supplied by the DUT? 

I measure the voltage on P22 VDD_nRF and P22 VDD_nRF' , I knows that the two pins have to be equal voltage (only when the power output is enable). It is just not intuitive to me why I need to enable power output to have the voltage equal?    When the power output is disabled I get a voltage difference on the two pins, why?

Please explain, if I enable the power output, will there be power go into my DUT from power profile kit? A schematic to describe the behavior can be good. 

[Priyanka]

Hi,

In the Amperemeter mode, the DUT gets power from an external power supply, say a USB, as you can see here:

I hope you get more clarity from our power profiler documentation.

Feel free to get back in case of further queries. But please expect a delay due to the Easter holidays and we are slighty understaffed at the moment.

Best Regards,

Priyanka

[szhaulai]

Hi 

The document wasn't clear enough  so I would like your team to help me understand it better.

In nRF Tools > Power Profiler Kit II > Using the Power Profiler app > Views

The figure shows that the power output needs to be enable. What does the enable mean? Does it mean the current from DUT go through the power profile kit (so that PPK can measure the current)? 

When I see the power output enable, I tend to consider it the same case as in source meter mode that the power is coming from the ppk. 

Best regards 

[Priyanka]

Hi,

Apologies for the delay as we just resumed work after the holidays.

I will try to explain the working of the PPK2 modes here: 

In Sourcemeter mode,

(1) The PC is connected via US to the USB - DATA/ÅPOWER part on the PPK2. Hence the PPK2 gets power from the USB and the data from PPK2 can be given to the PC via the same USB.

(2) Since it's sourcemeter mode, the PPK2 powers the DUT. So VOUT from PPK2 takes power to the DUT. (We also have a ground connected, and thus there are 2 pins connected.)

(3)The USB cable from the PC to the DUT is in order to supply power to few other components on it. 

Now when you "enable power output", it's what the name says. Basically it's to tell the PPK2 to supply power to the DUT and in sourcemeter mode, you can select the supply level.

Now, in Amperemeter mode,

(1) The PC is connected via US to the USB - DATA/ÅPOWER part on the PPK2. Hence the PPK2 gets power from the USB and the data from PPK2 can be given to the PC via the same USB.

(2) Since it's amperemeter mode, an external source (here it is the USB connection shown as (3) ) supplies power to the DUT. So supply from the DUT goes to  to the PPK2 via the VIN and goes out via the VOUT pin on the PPK2. (Then there is also the ground connected, and hence there are 3pins connected here. )

(3) The USB cable from the PC to the DUT, in this case, is in order to supply power to the entire DUT.

 Now here, the "enable power output" button just functions as a ON button for the PPK2 to start working. So don't take the literal naming into consideration here, as there is no "enabling" of power output happening here.

Hope this clears up your doubt.

-Priyanka

[szhaulai]

Thanks, that's pretty clear.