Unregulated SMPS works perfectly ok without output inductor, but it's required for regulation without high component stress.
The output inductor will try to short the secondaries of the transformer while it's discharging resulting in square waves. Resonance only shows up when there is no output inductor, or when the output inductor discharges before next cycle begins (and this just happens at low loads).
The following waveforms show the effect and were captured from an off-line SMPS that I did some time ago (half bridge). Blue trace is primary current, red trace is primary voltage. Pictures are no load, medium load and full load.
The output inductor will try to short the secondaries of the transformer while it's discharging resulting in square waves. Resonance only shows up when there is no output inductor, or when the output inductor discharges before next cycle begins (and this just happens at low loads).
The following waveforms show the effect and were captured from an off-line SMPS that I did some time ago (half bridge). Blue trace is primary current, red trace is primary voltage. Pictures are no load, medium load and full load.
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eheheh, stability problem, transient response, phase margin, gain margin....
...very complex..but not too complex
for now there aren't these problems. my smps work fine for me. obviously they can work better with proper skills, but i'm young..and lazy
now i understand "why" of that strange waveform, and i wanna say a "BIG thank you" for the replies, always accurate but extremely simply to understand.
thank you to everyone!!
EDIT: Eva, i see now the image you posted. Very examplary. Thank you!!
...very complex..but not too complex
for now there aren't these problems. my smps work fine for me. obviously they can work better with proper skills, but i'm young
..and lazynow i understand "why" of that strange waveform, and i wanna say a "BIG thank you" for the replies, always accurate but extremely simply to understand.
thank you to everyone!!
EDIT: Eva, i see now the image you posted. Very examplary. Thank you!!
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