EEVblog #324 – DC-DC Converter Testing – USB Supply Part 4Posted on July 31st, 2012 3 comments
Forum Topic HERE
Some quick testing of a 2W DC-DC converter.
Interesting Dave. So the sole purpose of this part is to provide DC-DC isolation? If so, I can see the use of this with a USB port. But it seems curious that it doesn’t regulate. There are several isolated switched mode topologies that regulate and provide decent efficiency, especially when we’re talking around 80%.
Also, I wouldn’t use an electronic load when measuring turn-on or turn-off output transient performance.
Oh comeon Dave, this was a pretty weak post…
Nothing done thoroughly, its a bit huschi-wuschi, why not test such stuff properly – its not that much more work….
And your electronic load seems to be a bit weird, too…can you trust such a behavior?
Please also consider the regulation dynamics of your load when you do these power-on step tests…your load certainly needs some time to regulate as well… (overshoot etc)
Cheers from Indonesia and keep the science up!
The 50 Hz from the electronic load is a classic symptom of a ground loop. Make sure both the scope and the electronic load are plugged in to the same power strip and verify the line, neutral, and ground are properly connected. If you have an isolation transformer, you can check this by running one device off of the isolation transformer. An unplugged UPS will work ( for a while) as an isolation xformer in a pinch.
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