....but surely a switcher consumes a certain amount of AC input current....
....and it must take this AC content from the flyback secondary....
.....so surely that means that there is now less AC ripple current in the secondary capacitor..
-because the switcher is going to be drawing some of it off.
Example:
In fact, i ran two simulations of 55KHz flybacks:
1. With a 13.3W resistive load
2. With a 13.3W pulsed current load (current pulsing at 50% duty cycle at 100KHz)
The ripple current in the main secondary electrolytic capacitor was the
same in each case
Here is the schematic of the pulsed load simulation:
https://i31.tinypic.com/2vxh9p0.jpg
Here is the schematic of the non pulsed load simulation:
https://i25.tinypic.com/23tii3t.jpg
Would you now say that the ripple current in Flyback secondary caps is not at all influenced by whether or not the load current is being pulsed or not?
LTSpice simulation files:-
.........................................
here is the LTSpice simulation of the non-pulsed load flyback:
https://www.2shared.com/file/r3s9xUWL/fbk__open_loop__45Hz__150VAC__.html
here is the LTSpice simulation of the pulsed load flyback:
https://www.2shared.com/file/SSyl1pu9/fbk__open_loop__45Hz__150VAC__.html