To accurately simulate the device, one must understand its four distinct internal blocks.
Start by finding a trusted TL494 SPICE subcircuit; use it in an LTSpice schematic for the most realistic results. For fast experiments, a behavioral model is OK but validate final designs with vendor models and bench testing.
Related search suggestions provided.
The TL494 is a classic PWM control IC widely used in power electronics, such as inverters and DC-DC converters. While it is not a native component in the standard LTspice library, it can be simulated by importing third-party SPICE models. 1. TL494 Core Architecture
The TL494 integrates all the functions needed for pulse-width modulation (PWM) control on a single chip: tl494 ltspice
Dual Error Amplifiers: Used for voltage and current regulation.
Adjustable Oscillator: Frequency is set by external components ( RTcap R sub cap T CTcap C sub cap T
Dead-Time Control (DTC): Provides a fixed or adjustable offset to prevent output overlap.
Output Control: Allows for either push-pull or single-ended operation. tl494.sub - texane/power_inverter - GitHub To accurately simulate the device, one must understand
power_inverter/ltspice/logic/tl494/tl494. sub at master · texane/power_inverter · GitHub.
If you need to create your own symbol, map these pins:
| Pin | Name | Function | |-----|---------|------------------------------| | 1 | IN1+ | Non-inverting input of error amp 1 | | 2 | IN1- | Inverting input of error amp 1 | | 3 | FEEDBACK| PWM comparator input (usually from amps) | | 4 | DTC | Dead-time control (0–3V) | | 5 | CT | Timing capacitor | | 6 | RT | Timing resistor | | 7 | GND | Ground | | 8 | C1 | Output transistor 1 collector | | 9 | E1 | Output transistor 1 emitter | | 10 | E2 | Output transistor 2 emitter | | 11 | C2 | Output transistor 2 collector | | 12 | VCC | Supply (7V–40V) | | 13 | OUT CTRL| Output control (GND=parallel, Vref=push-pull) | | 14 | VREF | 5V reference output | | 15 | IN2- | Inverting input of error amp 2 | | 16 | IN2+ | Non-inverting input of error amp 2 |
Several hobbyist and open-source communities have created reliable TL494 models for LTspice. Look for models from: Related search suggestions provided
A typical working model is a subcircuit (.subckt) that uses:
Example subcircuit header:
.subckt TL494 VCC GND RT CT DTC FB1 FB2 OUT1 OUT2
For advanced users: create a simplified model using voltage-controlled switches, a sawtooth generator (using a BV source with V=idt(1/Ct*V(osc_enable))), and comparators. This is educational but time-consuming.
Pro Tip: Once you have the tl494.asy symbol and .lib file, place them in the same folder as your LTSpice schematic. Use .include tl494.lib in the schematic.
The biggest challenge is that LTSpice does not include a native TL494 model in its standard library. You have three options: