slup080
I think the general idea is that you don't want the loops to have the same bandwidth to avoid "fighting" between the current and the voltage loops. The outer voltage loop is made slower. This is reasonable, since this loop is trying to control the average value of the output voltage. So it does not have to respond to something within a switching period. The output of the voltage loop error amp is used as the reference for the inner current loop. This loop is made a little faster so it can responde a bit more quickly. In traditional current mode control, the switch current is sensed and when the switch current reaches a set level, the switch is turned off. So in this scheme, the controller is acting to limit the current in the switch. In making the inner current feedback loop faster, we are reducing the delay from the time the current in the switch is sensed to the time we recognize that the switch should be turned off.
The following are materials from the Unitrode Power Seminars. I think you should browse through them to see if it is what you want. Some of the documents are for current-mode control other are more general but they have section on CMC.
**broken link removed**
**broken link removed**
**broken link removed**
**broken link removed**
**broken link removed**
You can find more information at (look at the bottom of the page for Archived Unitrode Seminar Series)
**broken link removed**
I hope that you find the material beneficial to your work.
Best regards,
v_c