For a flyback SMPS, if the output [with feedback] is loaded, the switching duty cycle goes up.
In this situation, what would happen to voltages on other outputs ?
(They remain constant I guess, but why?? Shouldn't they shoot up?)
Please explain.
Mike
Why guess that they would remain the same if you think they shoot up? Why would the other output go up as well ? If it did, by how much ?
Sounds like homework. We've done ours :-)
Hint: you may be looking at more than one phenomenon at the same time.
they are fed from diodes from the transformer secondary, as soon as one of the diodes is conducting the secondary voltage rises no higher.
Bye. Jasen
They will go up, unless the other outputs also contribute to the feedback loop.
Or unless the other outputs have some sort of secondary-side regulation (i.e., the addition of a linear regulator - not uncommon in switch-mode power supplies for the more lightly-loaded and otherwise unregulated/unmonitored outputs.
Bob M.
For an ideal flyback, all of the secondary output voltages will trac the one used for feedback. Practically though, when the output use for feedback is loaded more, the voltage coupled to the othe windings will be higher due to the uncoupled inductance (leakage L of the feedback winding. The other output voltages will go u slightly. You can see this small bump of voltage on any lower-loade output. It will be higher during the interval while the current i the feedback winding is increasing as the primary switch is turnin off
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