I am trying to verify my answers to part (a) in LTspice. I am having trouble with the CCM-DCM 2 model block, meaning I can't plot any reasonable output voltages. An astronomical voltage is being measured but not plotted. I only know this from putting the "probe" over the output and then looking in the lower left corner of the schematic window where there is some information displayed during a simulation. Using the HW4 CCM3 block, I have been able to check what I believe to be the CCM modes, but I'm at a loss for the CCM-DCM 2 block. Anyone else having problems?
- KT
I believe I've got my model correct. Did you use n=1/10 and make sure the inductance is the same on both transformer and CCM-DCM 2 block? If you want to email a picture I can check. adam.winter@colorado.edu
ReplyDeleteSeparately, have you derived a mathematical way to compare u in DCM vs CCM. When I use the DCM equation for u found on the slides it is always less than u=d. I'm not sure where i'm going wrong here because my plots clearly show DCM operation.
I found my problem. In the CCM-DCM 2 netlist, I had the alternative Ga section in place. I needed to change the comments to:
ReplyDelete** This Ga expression prohibits negative-current solutions:
Ga 0 a value={MAX(i(Et),0)}
** In case of convergence problems, the alternative Ga
** expression may work better
* Ga 0 a value={i(Et)}
- KT