RE: how to measure sleep current of custom board

awneil — Wed, 31 Jul 2019 09:50:15 GMT

You're welcome.

Don't forget to verify the answer once your issue is resolved.

RE: how to measure sleep current of custom board

pd@learner — Wed, 31 Jul 2019 09:45:34 GMT

Thanks For quick reply. I will check it

RE: how to measure sleep current of custom board

awneil — Wed, 31 Jul 2019 08:58:54 GMT

Assuming that your oscilloscope doesn't have any specific, special features to do this, then it is just a basic application of Ohm's Law.

You put a small sense resistor (often called a shunt resistor, or just "shunt") in series with your power supply, and use the oscilloscope to measure the voltage across it - then Ohm's Law gives you the current.

It's generally easier to put the sense resistor in the ground side - because the scope's ground clip is usually grounded.

The trouble with measuring very small currents is, of course, that you will only get a very small voltage - which may be at the limit of your scope's sensitivity.

A way to boos the voltage is to use a Current Sense Amplifier.

Although this document is rather dated now, the basic principle is the same as here:

http://www.antronics.co.uk/downloads/M1306B_Current_Traces.pdf

Alternatives

Nordic's power profiler:
https://www.nordicsemi.com/?sc_itemid=%7B3CF36A90-6BA3-4EFC-954C-D9C1AAFD638F%7D
Dave Jones's uCurrent:
https://www.eevblog.com/product/ucurrentgold/
Qoitech Otii:
https://www.qoitech.com/products
Angler Cirguits ZS-2102-A IOT Power Profiler
https://www.anglercircuits.com/
Keysight DC Power Analyzer
https://www.keysight.com/en/pc-1113932/dc-power-analyzer

etc, etc, ...