+5V (REF) | [R_DTC] | DTC (Pin 4) +------[R_GND]----+ | v GND Oscillator Frequency (RT and CT)
Locate a reliable open-source repository—such as the sunnyiisc Spice-Model Collection on GitHub or texane's Power Inverter repository —and copy the plain text .subckt tl494 code block. Save this block locally on your PC as a file named TL494.sub . Step 2: Auto-Generate the Graphical Symbol ( .asy )
Tie Pin 13 to Pin 14 (VREF). Transistors 1 and 2 switch out of phase, restricting each output's maximum duty cycle to 45%. 4. Troubleshooting Common Simulation Issues
RT=1.2120 kHz×1 nF=10 kΩcap R sub cap T equals the fraction with numerator 1.2 and denominator 120 kHz cross 1 nF end-fraction equals 10 k cap omega In LTspice, place a resistor on RT and a capacitor on CT to observe a sawtooth waveform on the CT pin during transient analysis. 5. Running the Simulation and Analyzing Waveforms tl494 ltspice
| Pin | Name | Description | |-----|-----------|---------------------------| | 1 | IN1+ | Error Amp 1 non‑inverting | | 2 | IN1- | Error Amp 1 inverting | | 3 | FEEDBACK | Compensation / PWM input | | 4 | DTC | Dead‑time control | | 5 | CT | Timing capacitor | | 6 | RT | Timing resistor | | 7 | GND | Ground | | 8 | C1 | Output collector 1 | | 9 | E1 | Output emitter 1 | | 10 | E2 | Output emitter 2 | | 11 | C2 | Output collector 2 | | 12 | VCC | Supply (7–40 V) | | 13 | OUT_CTRL | Output mode control | | 14 | REF | 5 V reference output | | 15 | IN2- | Error Amp 2 inverting | | 16 | IN2+ | Error Amp 2 non‑inverting |
Keep in mind that SPICE syntax can differ between simulators. Models designed specifically for LTspice, including subcircuits with other files, might not work properly in other environments like KiCad's ngspice. The models are designed for LTspice, so ensure you are using it for your simulations.
fosc=1.2RT×CTf sub o s c end-sub equals the fraction with numerator 1.2 and denominator cap R sub cap T cross cap C sub cap T end-fraction For a target frequency of 50 kHz, try Setting the Dead-Time Control (DTC) Pin 4 controls the minimum dead-time. +5V (REF) | [R_DTC] | DTC (Pin 4)
Mastering TL494 PWM Controller Simulations in LTspice: A Comprehensive Guide
) file into the LTspice library subfolder, typically located at /Documents/LTspiceXVII/lib/sub/ Move the Symbol File : Place the file into the symbols folder, such as /Documents/LTspiceXVII/lib/sym/Misc/ , to make it selectable in the component menu. Include Directive
The is one of the most resilient and widely manufactured Pulse Width Modulation (PWM) control chips in the history of power electronics. Designed by Texas Instruments and multi-sourced by numerous chipmakers, it serves as the foundational controller for ATX computer power supplies, DC-DC buck/boost converters, and high-frequency inverters. Transistors 1 and 2 switch out of phase,
models into LTspice. Because LTspice is generally compatible with the SPICE standard, many models for similar double-ended controllers like the can be adapted if a direct TL494 model is unavailable. Pro-Tips for TL494 Simulations Label Your Nets
Leaving Pin 4 floating can create unpredictability in your simulation. To establish a minimum dead-time (
