Tl494 Ltspice

The TL494 is a legendary integrated circuit. Introduced in the late 1970s by Texas Instruments, it has become the backbone of countless switch-mode power supplies (SMPS), from simple boost converters to sophisticated offline flyback designs. Its longevity is a testament to its robustness and flexibility: it features pulse-width modulation (PWM) control, two error amplifiers, a dead-time control comparator, and an internal oscillator—all packed into a 16-pin DIP or SOIC package.

This guide provides a comprehensive overview of using the TL494 PWM controller in LTspice, including how to set up the simulation, model the component, and analyze a power supply circuit. Introduction to TL494 and LTspice

: Check the voltage on Pin 4 ( DTC ). If the macromodel interprets a voltage higher than

Click Simulate -> Edit Simulation Cmd .

Pin 4 controls the minimum dead-time (the period where both output switches are forced OFF).

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.

: If you did not place the .sub file into the system directory, add the following text command anywhere on your schematic: .include TL494.sub Use code with caution. Running the Analysis tl494 ltspice

Because the TL494 is not manufactured by Analog Devices, its simulation model is not included in the standard, native LTspice component library. To use it, you must acquire a third-party SPICE macro-model. 1. Where to Find the Model

But designing with the TL494 can be tricky. The switching behavior, loop stability, and timing dependencies are difficult to predict with hand calculations alone. This is where , Analog Devices’ high-performance SPICE simulator, becomes indispensable. By simulating a TL494 model in LTspice, engineers can validate their designs, tweak compensation networks, and visualize waveforms before ever soldering a component.

V_OUT (Power Stage) | [R_top] | +-----> Pin 1 (1IN+) <-- Non-Inverting Input | [R_bot] | GND : Connect Pin 14 ( REF , ) to a resistor divider to feed exactly into Pin 2 ( 1IN- ). The TL494 is a legendary integrated circuit

Move the subcircuit file ( tl494.sub or .lib ) to the subcircuit directory: C:\Users\[YourUsername]\Documents\LTspiceXVII\lib\sub\

What to watch:

pin; they may only function in push-pull mode even when configured for parallel operation by switching the pin from cap V sub r e f end-sub to GND [3]. Waveform Overlap This guide provides a comprehensive overview of using

* TL494 Subcircuit for LTspice * Pin order: 1IN+ 1IN- 2IN+ 2IN- FB COMP CT RT GND C1 C2 VCC OUT1 OUT2 * Simplified functional model: oscillator, PWM comparator, error amps, outputs

Simulating power controllers often reveals discrepancies between the "ideal" digital logic and "real-world" analog behavior. Output Voltage Swings