I am designing a camera that is powered by a 5 V DC power line. I need to evaluate the peak power consumption of the device during image capture. At a pixel clock period of 40 microseconds I expect that I can do this with a power monitoring rate of 10 kHz. The camera has an average power consumbtion between 1 and 2 W.

I found the ADM1293 power monitoring IC. The sampling rate is not explicitly stated, but with the clock rate of 400 kHz i expect it should be sufficient.

Am I correct or would I need something faster?

Is this circuit maybe too much for my purpose?

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    \$\begingroup\$ Maybe an oscilloscope, that you can use later for other experiments? \$\endgroup\$ – Marko Buršič Mar 27 at 9:15
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    \$\begingroup\$ Are you sure you don't mean 40 nanoseconds (25 MHz)? 40 microseconds would be more like the line period for most sensors. \$\endgroup\$ – Dave Tweed Mar 27 at 11:12

A DSO (Digital Storage Oscilloscope) would be the proper tool to use in order to record the fluctuations of current in your circuit.

While purpose-made oscilloscope current probes are available in the market, they are not inexpensive, and high performance/high precision units can cost thousands of dollars. This solution may be practical in your situation if you intend to do long-term or frequent/production measurements.

A more cost-effective solution would be to use a precision shunt resistor of a known value in series between the negative supply rail and the ground of your circuit. You would then measure the voltage across the resistor with the oscilloscope probe, and use Ohm's law to calculate the scale for your oscilloscope. Many DSOs can even be programmed with custom scaling so you can calibrate your oscilloscope's sample captures.

Which you choose really depends on how much money you want to spend versus how much precision you require.


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