LM5116-12EVAL: Efficiency measurement tools used by ti.

TI is a large company with many different sites.  The equipment will vary from location to location and in fact will vary among test benches even in the same lab.  I personally use a rather complicated automated set up under customized computer control, but you do not need to do that to get accurate results.  The key point is to correctly measure the input voltage, input current, output voltage and output current.  As a rule of thumb, measure the input and the output voltages directly on your application board as close to the actual circuit inputs and outputs as possible.  If you are using an electronic load,, it is generally acceptable to use the internal current meter to measure the current.  For the input you should use a current meter or shunt resistor to measure the current.  You can use a shunt resistor on the output current as well.   See this link for some video training:

training.ti.com/engineer-it-how-test-power-supplies-measuring-efficiency

Dear John,

It is the easiest answer anyone can give. I need your expertise or someone who is working with these tools.

If there are various tools, than tell me two or three tools that you use to measure the current. If using shunt, what will be value to use for measurement of 30A current. 

I need to know about the tools. accuracy depends the way of measurement but tools also.

I am using clamp meter to measure the efficiency. it says 3% accuracy in whole range of 400A.

And when current is low as 10A, 0.1A inaccuracy can leads to high error in accuracy.

Even if we use shunt, how can we sure that it measures the current accurately with all these ripples at full load.

When I get back in  the office on Monday, I can give you the specific equipment that we use.  Be prepared for sticker shock as I am sure the setup is quite expensive. It is all run thru GPIB and National Instruments LabVIEW software control.  Our lab no longer uses shunts or manual efficiency measurements, but when we did the equipment were calibrated by an outside lab to ensure accuracy.  Probably the easiest way forward is for you to tell us what equipment you have available and then we can advise you on best practices for use.