Orcad Pspice Gate Driver+Mosfet and Pspice

[Brandon Yau]

Hi everyone,



In the first picture, the circuit does not work when it is connected to the sbreak switch.
In the second picture, the circuit works when it is connected to the gate driver (E) and the mosfet (IRF150), but the result goes wrong.

I connected the upper dual flyback circuit and the lower compensated error amplifier+PWM circuit following the specs, the result should be correct. When I just construct the simple dual flyback circuit, the result is correct and works well with the sbreak switch. When everything is connected together, the sbreak switch fails.

Whats wrong with it?

 

[atripathi]

I suspect the feedback loop may not be working as expected. You may want to try the open loop circuit simulation first, break the loop and run the flyback at fixed duty cycle. This will help get identify the problem if any in power and feedback sense circuit. If this work, you can try closing the loop and see if simulation works. In lot of cases error amplifier gets saturated at one end of power rail and this causes circuit to stop function as there is no switching and hence no corrective action.