Hello, I contructed a simulation model with LM5119 which is same us the circuit of evaluation kit LM5119EVAL, however, when I apply transient analysis on this model, it shows a error called "operating point not found, component U1.XVC0.XU5.D1", I don't know what does that mean, can you suggest any solution? Thank you very much.
Lee,
Before a transient run can occur, the DC operating point must be calculated. This is essentially a starting point for solving the matrix at time point zero. In some cases, the DC operating point of certain components may not be solvable and the simulator will issue the error that the DC operating point cannot be found and then list the component for which the issue has been observed. The problem is that the issue may have nothing to do with the listed component. There are many ways to try to resolve this issue. It may be dependent on the simulator settings, the device model, or the circuit topology. All of these can play a role in why the error is occurring.
It is always best to start with a known good circuit (a reference design that simulates properly). In this case, I do not believe that there is a TINA-TI reference design for this part and you have imported the unencrypted PSpice model into TINA-TI. The quickest solution would be to try using intitial conditions (the two additional options when selecting a transient simulation:
If these do not work, you could use WEBENCH® Power designer from the product page to create a known good design and try it in TINA-TI. You would then have the simulation from WEBENCH® as a reference. I am not sure how much simplier a created design would be than the EVM design.
You can also try adjusting the DC parameters in TINA-TI that might aid in a solution being found. There really isn't set way to fix this kind of issue since there are so many things that could be causing the issue. Here is the full list of items that could be changed (Analysis-->Set Analysis Parameters):
