Measurement current consumption of low power circuit

Question

I have a circuit which has uC, Bluetooth module and some other ICs. Current consumption of it varies between 100uA and 20mA. I want to see current waveform using oscilloscope. I worked before high current measurement(above 1Ampere) using low-side sensing technique but not so small this. How to setup a small circuit to see current values of each phase(sleep, active, transmission) separately?

Note: The circuit is powered by battery

Does this answer your question? [How to Measure Power Consumption on Extremely Low Power Devices?](https://electronics.stackexchange.com/questions/294180/how-to-measure-power-consumption-on-extremely-low-power-devices) — KubaFYI, Jan 07 '20 at 11:45
Have you watched this EEVBlog video: https://www.youtube.com/watch?v=Dh0xYu8YvaE&t=23s where Dave demonstrates using the integration function of an oscilloscope to measure power consumption of a uC. — Bimpelrekkie, Jan 07 '20 at 11:47

score 1 · Accepted Answer · answered Jan 07 '20 at 11:46

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Use "shunt" resitor (low ohm resistor) in power supply line and measure voltage drop on it. Current is low, so resistor dont have to be real shunt resistor.

answered Jan 07 '20 at 11:46

ufok

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With a 10ohm serial resistor, i can follow the waveform. This is OK for me. – Berker Işık Jan 07 '20 at 12:56

score 0 · Answer 2 · edited Jan 08 '20 at 16:52

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Why not use a current shunt amplifier.

It should do the job, make sure to use the right resistor value, following the gain of the amplifier.

edited Jan 08 '20 at 16:52

Elliot Alderson

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answered Jan 07 '20 at 12:00

Delphesk

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And the op amp must be a true "RRIO" Rail-to-Rail In and Out type. – rdtsc Jan 07 '20 at 13:10
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Please provide a link or a citation for the graphics in your answer. We want to be sure to give credit to the original creator. – Elliot Alderson Jan 07 '20 at 17:16

Measurement current consumption of low power circuit

2 Answers2