A typical push-pull converter design might call for:

PWM Comparator

.ENDS TL494

Offers a dedicated input to establish a fixed minimum dead-time, preventing shoot-through currents in push-pull configurations.

To run a soft-start routine within LTspice, connect an RC network to Pin 4. This slowly pulls the dead-time voltage down from VREFcap V sub cap R cap E cap F end-sub

Apply a variable voltage source to ranging between 0.5V and 3.5V to visually track changing duty cycles on your output waveforms. Troubleshooting Simulation Failure & Convergence Errors Electronics - Hacking the TL494 LTSpice Model - MK Dynamics