Hi Aaron, No worries. I actually don't see any published data on the Rohm switcher for stability analysis, so nothing to really compare that to. It does seem to be measuring correctly with how the converter behaves though. The active PFC converter is similar to what can be found in this ST document:...

Hi Aaron, Reporting back now that I've had time to do quite a few things with the tool. I did find with a buck converter EVB (a Rohm 9B300) I am playing with that I can get a clean response, however there always seems to be some noise on the line. Note I did see weird things happen when I had the in...

Hi Aaron,

I just checked the XML, and yes that was actually set for high noise mode. One thing I forgot to switch back. I must've done those plots at 120Hz to 500Hz.

Tomorrow I can try another plot setting the minimum cycles captured down to 1 and see what it looks like.

Thanks,
Mitch

Morning Aaron,

Compressed diag folder is attached. Note I had to get this on here being sneaky... that's really a 7z file for the 256k size constraints but the forum here won't accept a 7z file. Zipping was a bit too large, so just rename the extension 7z to unpack it.

Thanks,
Mitch

Hi Aaron, Those files I found in the FRA4PicoScope/diag folder, and I copied the names from the svg files over to the png's. Note this was made from 1 run as I never ran that before, and I see all the timestamps were at the same time. That sweep was from 10Hz to 500Hz if I recall correctly with 10 s...

Hi Aaron, Lots of attachments this time, and let me know if I've collected the appropriate data for debugging this. Before looking at the converter's plots, I recorded more step responses. One example is shown with 120VAC at the input going from a 0mA to 700mA load. With the damped oscillation in re...

Thanks, Aaron. Yesterday was long, since looking at the first curve I read that wrong. The bump up is the 120Hz ripple (just above 100Hz) which is the huge ripple causing grief. Ripple is about 2-4Vpk-pk. For low noise, yes I tried that to get beneath the 120Hz limitation and to see just what it wou...

Hi Aaron, I finally got around to testing out my active PFC converter. Note the results are looking a bit weird here, but wanted to share what I found. The compensation tuning on the converter is stable and works well during load transients and shows no overshoot, so to start I know this converter i...

Hey Aaron, Sure. In college I had luck to have a very knowledgeable professor in power electronics. We used Fundamentals of Power Electronics by Erickson. This book is pretty good overall and things are explained well. In that class the instructor had us derive the control transfer functions for a f...

Not to veer this too far into SMPS control loops... but hey may as well add to the chain. A converter shouldn't have multiple crossovers but it could happen. That would be something interesting where there typically is not correct pole/zero placement and the gain of the closed loop bounces around ze...

Thanks again Aaron. That was one part I overlooked on the bitbucket site you've got since I was looking for a UI cue. It was easy enough to change and I've got that mode set. For pretty much all SMPSs, fc needs to be quite a bit lower than the switching frequency. It depends on the converter topolog...

Hey Aaron, The transformer I showed that data on was a regular 50VA toroidal core power transformer I happened to have lying around. For my application I know the fc of my converter needs to be quite low (around 50Hz to 70Hz), and I know these cores are decent up to a few hundred Hz. It's surprising...

Hi Aaron, Thanks for the remote debug. It looks like since I am new on the forums my earlier post was delayed (https://www.picotech.com/support/topic14311-90.html?hilit=hexamer#p74511) I have it working now and am checking to see what transformers I have for some SMPS stability tests. I've attached ...

Hey Aaron, I was able to get it: I had the 64 bit SDK installed. Once I also installed the 32 bit SDK everything seems to be working. I have a switching power supply I'd like to do a stability test on and will use a small isolation transformer from the picoscope to the feedback loop and see if this ...

Hi Aaron, Nice concept here for the bode plot analyser. I've got a 5442B and have tried this out just now with a simple RC network of a 1uF cap and 6.8k resistor to form a high pass filter. For me, using Windows 10 with this I don't get good data but a flat line in the graph. Exported to excel I get...