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UCC28710: ucc28710- Frequency response analysis

Part Number: UCC28710


An interesting question: how would one measure traditional " frequency response" to get Gain-Margin & Phase-Margin?

If you add too many extra components to create a Test circuit, then FRA will be their response perhaps not of the switching circuit.

In fact, does FRA apply to such nonlinear feedback systems?

What other methods do we have to demonstrate the "stability " of these circuits? 

Can we set up to measure "output impedance" & "input impedance" ?


  • Hello Robin,

    The UCC287XX family of PSR flyback controllers cannot be measured for Gain and Phase margin in the usual Bode-plot way, because there is no point that can break the feedback path without interfering with timing signals a the VS pin.

    The only method we know of for assessing stability is to apply load steps to the output and assess the degree of ringing (if any) on the step response.
    Note: Loop stability is a small-signal property, so please avoid using large load steps for the testing. The deviations are easier to see, but may obscure the true response.