Tl494 Ltspice ((new)) May 2026
Simulating the TL494 in LTspice is a standard task for engineers designing switch-mode power supplies (SMPS). While the TL494 is a legacy PWM controller, its versatility in push-pull, half-bridge, and buck converter topologies keeps it relevant in modern hobbyist and industrial designs.
1. Where to find a TL494 model
- Texas Instruments – official PSpice model (can be adapted to LTspice)
- Onsemi – TL494 model in
.libformat - User libraries – e.g., from the LTspice Yahoo Group (now archived) or GitHub repositories
Part 2: Sourcing a Working TL494 Model for LTspice
This is the most common hurdle. LTspice does not ship with a native TL494 model. You have three options: tl494 ltspice
is a versatile Pulse-Width Modulation (PWM) control circuit widely used in switch-mode power supplies (SMPS) for its fixed-frequency operation and dual output capability. Integrating it into Simulating the TL494 in LTspice is a standard
| Error Message | Likely Cause | Solution |
|---------------|--------------|----------|
| "Time step too small" | Fast switching + floating node | Add 1MEG resistors from each output to GND. Reduce maxstep in .tran. |
| "Singular matrix" | Missing DC path to GND | Check the voltage feedback divider; ensure error amp inputs are not floating. |
| Output always high or always low | Dead-time pin too high (>3V) or wrong oscillator | Set DTC <0.6V for max duty cycle. Verify RT/CT values. |
| No oscillation at pin 5 | Missing ic initial condition | Add .ic V(osc_pin)=0.3V or use startup flag. | Texas Instruments – official PSpice model (can be