How do you measure real current on your module?

Wireless Connectivity Ultra-Wideband
1

Hi There!
How do you measure real current consumption from this module? Im trying to measure mine but I can’t go as low as uA range in my oscilloscope. (Rigol DS1052E)
I mean, I use a 0R22 shunt resistor in series with the battery. So when I measure 4-5mV (LP mode off), this means 15-20 mA, which is expected
Then I switch LP=1 and then I see voltage get down to ~1mv. This means 4-5mA, which doesn’t make sense. But then I disconnect the power from the module and I still get readings on my oscilloscope around 0.8–1.2mv!! WHY? I don’t know. but I actually touch the probe tip with the ground test lead and I still get these values on screen. I tried an auto-recalibration in the TOOLS menu but nothing changed.

I could use a larger shunt like 5Ohm so the read voltage would be 25 times bigger, but the TX/RX spikes during UWB communication would lead to a large voltage drop in this resistor that the module wouldn’t probably stand it.

Any other way to achieve valid readings of uA currents??

Thank you!

2

If you are hitting issues due to your test equipments noise level then use better test equipment. :slight_smile:

If you can keep the system in lower power mode for a long time then use a nice large series resistor but short it out while the system starts up. Once it’s in low power mode remove the short circuit and make your measurements. Not a practical solution for going in and out of low power but OK for a one off measurement.

3

Well I’m trying to measure the power consumption between TX/RX spikes, those would happen at a rate (with our current configuration) of once a second, so I can’t really move much stuff and resistors between spike and spike. I was told to build an amplifier with a LNA IC in order to keep the low ohm resistor shunt but get amplified readings 100 times larger with the amplifier. Spikes would get out of bounds but I don’t care for those, I do care for the deep sleep time consumption