Minimum OScilloscope requirement for SMPS

[sunil21]

My flyback and Forward converter Designs are in the range 50khz-100khz..
I want to know if a 50mhz oscillosope is enough for this purpose. (There is one i can get - 50MHZ)

 

[BradtheRad]

It should do so easily, since my own 1 MHz 'antique' Tektronix tube oscilloscope has no trouble displaying 100 kHz waveforms.

 

[treez]

yes 50MHz ok, but remember the max rise time it will be able to depict is 0.35/50e6 seconds.
Anything rising faster than that will get filtered.

 

[sunil21]

I got an other option to get one of 25mhz from my friend..
CHecking flyback ringing etcc... will that be enough?
or have any workaround with this one scope?

 

[KlausST]

Hi,

25 milliHertz won't be sufficient. ;-)

Now some hopfully useful information:
I'd say a 50MHz analog scope should work, but in detail nobody knows your ringing frequency.

For a digital scope I'd go for way higher than 1 MSampl/s. There are goid and cheap ones with 1GSample/s and higher.
But even a digital scope needs to have a sufficiently high analog bandwidth. >= 50MHz.

2 channels at least. High voltage probes, current probes.

Klaus

 

[treez]

Get decent enough memory depth too.....no point in being able to depict a super sharp rise in great detail if thats all you can see in the window........you need it to be able to remember a good length of the waveform with decent enough resolution, and show that to you.

 

[schmitt trigger]

Probes. Klaus has already mentioned HV and current probes.
I only would add a differential probe.

And make sure the current probe is hall-effect based. Cheaper transformer based probes have low frequency limitations. And certainly can’t display DC.