Internal Reference (5V) R_ref 14 0 1k E_ref 14 0 VALUE=5.0
Since the TL494 is a legacy part, most semiconductor manufacturers (Texas Instruments, ON Semiconductor) provide SPICE models on their websites. However, these are often in PSpice format. For LTspice, it is often easier to use a simplified behavioral model or a converted subcircuit.
: Tie Pin 4 ( DTC ) directly to ground for minimum dead-time (
To make the component permanently available in your LTspice library, save the files to the following paths on your computer: tl494 ltspice
Right-click the component, select "Open Symbol", and ensure the "ModelFile" attribute points to your tl494.sub . 3. Basic TL494 Simulation Example: Buck Converter
TI provides PSPICE models for the TL494 on its product page. These models are generally compatible with LTspice.
In this comprehensive guide, we’ll explore everything you need to know about simulating the TL494 in LTspice — from obtaining reliable SPICE models to troubleshooting common errors, from designing basic PWM generators to constructing full-blown power converters. Whether you’re a student learning power electronics or a professional developing commercial power supplies, this article will help you harness the full potential of the TL494 in your simulations. Internal Reference (5V) R_ref 14 0 1k E_ref 14 0 VALUE=5
Verify that the REF pin (Pin 14) shows a steady 5V during simulation.
[ f_osc = \frac1R_T \cdot C_T ] (For RT in ohms, CT in farads, f in Hz) Actual output frequency = ( f_osc ) in single-ended mode, ( f_osc/2 ) in push-pull.
(Note: The code above is a highly simplified behavioral model for demonstration. For precision engineering, download the official PSpice model from Texas Instruments and convert the syntax.) : Tie Pin 4 ( DTC ) directly
When operating in push-pull mode (pin 13 connected to VREF), some users see overlap between the two outputs instead of alternating pulses.
To execute the simulation, add a transient command to your schematic: .trans 2m Use code with caution.
Save the model text as TL494.sub in the same directory as your LTspice schematic.
To test the maximum possible duty cycle, tie .