Settings for maximum current draw from PPK

[Sridhar Jonnavittula]

Hi,

We want to measure our external custom board which is not based on nRF52 chip. That board has current consumption header and it's chip draws maximum current of 60mA at bootup time.

So can you suggest us a way for connections (using PPK, nRF52840 DK, regulated power supply) to supply external board's chip.

Also we tried at our end with different ways of connections and we can't succeed in bootup of custom board's chip.

We have seen in link that external boards can draw upto 400mA from PPK's external connector, but we are not getting us exact reason.

So please help us out.

Thanks in advance

[Stian Røed Hafskjold]

I think the best way would be using the PPK as a standalone device.

Do not stack the PPK on top of the nRF52840 DK, but use a 10 pin SWD cable from the debug out on the nRF52840 DK and to the debug in port on the PPK.

Use the same setup as in figure 2 in this link: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.tools/dita/tools/power_profiler_kit/PPK_user_guide_PPK_on_customHW_standalone.html?cp=5_6_5_5

The DK can be used as the SEGGER JLink shown in the drawing.

[Sridhar Jonnavittula]

Hi,

We followed the same setup in above link.

In regulated power supply we can see current drawn at 60mA and

voltage dropped to 2.7v when tapped the P16 pins of PPK in multimeter.

This means enough current(more than 60mA) is not supplied from PPK to external board.

In this case our external board is not booting up yet because it is needed more than what PPK is supplying.

Currently our focus is to bootup the external board. After bootup successfully we can start profiling. Hence we are not connecting any JLINK to PPK software.

So do we need to calibrate/ change any settings of PPK like resistor calibrations, voltage regulator etc?

Thanks

[Stian Røed Hafskjold]

You should connect the JLink to the PPK and start the PPK software. The software does the resistor calibration and switching between the measuring resistors.

[Sridhar Jonnavittula]

OK. We will do that also for sure and with the above assumption we were not doing that.

What is the maximum inrush current the PPK supports for the external board?

[Stian Røed Hafskjold]

In the PPK specification it is stated 70mA. This is probably on the safe side.