Start-up and steady-state models of microcontroller

Thread Starter


Joined Aug 22, 2021
I've been looking at UCC28C43 models provided by TI. Why do we need two different Spice models such as "Transient steady-state" & "transient start-up" for MOSFET driver IC? How do we use them? When do we need these analyses?
Do all microcontrollers in power electronics have such separate models? For the "Transient steady-state" model, if it is steady-state why is this transient?


Joined Feb 24, 2006
It all has to do with the way simulations run. SPICE does simulations in two steps:
  1. Establish a DC operating point for the circuit
  2. Run a linearized simulation for small signal variations around the operating point.
In the Transient startup model and the Transient steady-state model there are different starting conditions that establish the DC operating point and the subsequent evolution of the linearized small signal equations. Having two different models avoids certain types of errors and slowdowns in simulations where the traditional approach has problems.

BTW - why do you think the UCC28C43 is a microcontroller? It is actually a building block for building an SMPS (Switch Mode Power Supply). No programming is required.