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Tool/software:
Hello,
we have a design where an LM5066I is used to switch 48V. In our application, power switching requirements are pretty low, usually well below 40W.
To get some acceptable power measurement accuracy, we use an Rsense value of 47mR.
So for testing what I did is connect an electronic load to the circuit. That load can be configured to draw a constant current (and I verified with a multimeter that the current values are indeed correct), and I did that and increased the current in 50mA steps, each time measuring the voltage across Rsense and reading out the raw Iin ADC measurement values from the device (register 0xD1/0x89) (CL set to 50mV).
I noticed a few things:
So I do not really understand what is going on here. Is this a layout issue, is it a device issue, am I misunderstanding how the device works and this is expected behaviour?
Here is an image of the circuit we're using. Note that originally, we were using the LM5066 and then later switched to the LM5066I. But except different calculation coefficients and a different Rpwr value this should not have any impact.
Thanks Kunal!
BTW, I forgot to mention: The ADC value that is plotted in the diagram is the median over 1000 measurements. Median seems better to filter out the bogus values than using the average. So the plotted value is not a one-shot, it is across 1000 measurements.
Hi Sean,
It is difficult to say it is device issue as they have passed final test program which checks accuracy. I will recommend you evaluate device on our EVM using GUI.
Regards
Kunal Goel