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UCC28711: MEASURING SMALL SIGNAL LOOP RESPONSE

Part Number: UCC28711

Hello:

If I added a small 10 Ohm resistor in series with the upper resistor of the divider for the VS pin, will it offer the possibility to measure a small signal loop response by injecting a small signal sweep in a manner similar to a typical dc-dc converter circuit loop response measurement?

Is that a good "injection" node?

Looks like!

Appreciate any comment on this or suggestions for doing the same.

r

  • Hi Robin,

    The UCC28711 family of PSR flyback controllers cannot be measured for Gain and Phase margin in the usual Bode-plot way, because it will interfere with timing signals on the VS pin if we break the feedback path there.

    You can apply load steps to the output and assess the degree of ringing (if any) on the step response for measuring stability.

    Regards,

    Harish