Current consumption is different between ampere meter measurement and source meter measurement using PPK II

[Tai]

Hello everyone,

I'm testing current consumption of nRF52 dev KIT (PCA10040). The test application is a BLE application. I tried with two methods for measuring current consumption (Ampere and Source meter). However, I got a significant difference between two methods.

The setups of both methods for current consumption are attached below as well. I've followed several video tutorials for this setup.

Using ampere meter, I got every low current consumption as shown in the following figure (147 uA for BLE advertising and 225 uA for BLE connection initialization). In contrast, using source meter method (set 3V to external supply) I got very high current consumptions with > 1.6 mA for BLE advertising and > 3.7 mA for BLE connection initialization. 

Are two methods supposed to give the same current consumption? Or please let me know if I have any wrong setup for this. Thanks!

[Tai]

Update: I changed my setup for source meter method with the reference setup from PPK II user guide. I got the same current consumption as measured with ampere meter method. 

Here is very helpful post for those who is trying to measure current consumption with custom board - here

Reading more information with this topic in another post, it mentioned about disabling NRF_LOG_ENABLED and verifying the DEBUG flag to significantly reduce the current consumption. Could you please help me to explain the DEBUG flag and how does it effect to power consumption?

[Daniel01]

Hello, I have a question. I have the PCA10040 version 3.0.4. To correctly measure the current consumption, I need to solder SB12, but to continue programming normally, do I need to desolder SB12? Or can I keep it soldered and continue programming normally?

[Simonr]

Hi Daniel

In order to measure current consumption on the nRF52832 DK all you need is to cut SB9. If you want to restore normal DK function, you can apply a jumper onto header P22, and then remove it whenever you want to measure current again.

SB12 only necessary to short if you are using the an external power supply on P21 to power the board, and if so, you will also need to desolder/cut SB12 to reconnect the protection diode to be able to safely power it with the USB on J2.

Best regards,

Simon

[Daniel01]

Hello, thank you for your advice. In the end, I used this configuration and the measurement turned out well.