Tool/software:
Hi everyone,
I’m trying to simulate the LM5149 in PSPICE, but I’m not seeing any switching activity from the MOSFETs. I'm simulating the startup circuit that comes with the spice file found at the TI webpage of the LM5149 and was planning on building upon this. The output seems to have no direct sign of PWM operation. This lead me to believe that maybe some averaging is done by the simulation. In the attached image of the simulation outputs, the top graph displays the gate source voltage of both MOSFETs. This rises to a DC value. The same kind of behaviour is seen in the middle graph which is the point between the MOSFETs in the synchronous buck converter. I'd expect this point to be switching too.
Has anyone encountered this before? Any help would be appreciated!
Thanks in advance.
