The combination of Texas Instruments’ TL494 Pulse-Width Modulation (PWM) controller with Analog Devices’ LTspice simulation tool is a potent, albeit often tricky, pairing for power electronics engineers and hobbyists. However, this is not an officially supported configuration, leading to frequent challenges, from sourcing the right files to debugging elusive simulation errors.
Switch the LTspice solver configuration from "Normal" to "Alternate" under the Control Panel (Tools > Control Panel > SPICE). Inaccurate Reference Voltage
If you need to calculate the precise resistor and capacitor values for a specific frequency, or require a simulation example for a buck-boost configuration, I can provide that information. Analog Devices LTspice - Analog Devices tl494 ltspice
Some poorly coded third-party models fail to regulate the 5V REF pin properly if the simulation supply ramp is too steep. Ensure your VCC source has a realistic rise time (e.g., 100 microseconds) rather than an instantaneous ideal turn-on step.
Place the TL494 subcircuit (requires creating a symbol from TL494.sub ). Inaccurate Reference Voltage If you need to calculate
The compensation network is connected to Pin 3 (Feedback/Compensation).
Click Simulate -> Edit Simulation Cmd .
Some models may not properly handle extreme dead-time settings; ensure DTC is properly biased.
Below is a functional SPICE model for the TL494 that can be used in LTspice. Copy the text below and save it as a file named TL494.sub in your LTspice library folder (typically C:\Users\<User>\Documents\LTspiceXVII\lib\sub ). Place the TL494 subcircuit (requires creating a symbol