Please note these two equivalent offline flyback simulations.
-one has cascoded opto feedback , and the other does not.
Note how the non-cascode version has 2V of overshoot on vout at start-up. Due to the lack of a cascode, this overshoot is virtually impossible to get rid of whilst keeping sufficient gain and phase margin. The cascaded version has no overshoot, and achieving this was simple.
Cascodeing is extremely cheap to do...why does everyone not do it?
Schematics and LTspice simulations of offline flybacks given. (one cascode and one no-cascode, but they are the same power level, vin, vout, np/ns, Fsw.)
-one has cascoded opto feedback , and the other does not.
Note how the non-cascode version has 2V of overshoot on vout at start-up. Due to the lack of a cascode, this overshoot is virtually impossible to get rid of whilst keeping sufficient gain and phase margin. The cascaded version has no overshoot, and achieving this was simple.
Cascodeing is extremely cheap to do...why does everyone not do it?
Schematics and LTspice simulations of offline flybacks given. (one cascode and one no-cascode, but they are the same power level, vin, vout, np/ns, Fsw.)
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