Tl494 Ltspice

Some TL494 models reference external files like universalOpamps2 or level.2 opamp models. If these are missing, you’ll get errors like universalOpamps2 file library is included in the TL494 file, but there is no ltspice software in the library itself .

To implement a safe margin preventing shoot-through in half-bridge configurations, create a voltage divider from (Pin 14) to provide roughly 0.1V to 0.3V to the DTC pin. Selecting Output Modes

: Right-click on any component to modify its parameters [8]. Micro Units : Use u for micro (e.g., 10u for ) [9].

Simulating the TL494 PWM Controller in LTspice is a staple in the world of power electronics, frequently used for fixed-frequency pulse-width modulation (PWM) control in push-pull, half-bridge, and full-bridge switch-mode power supplies (SMPS) tl494 ltspice

Set via an external resistor ( RTcap R sub cap T ) and capacitor ( CTcap C sub cap T

Texas Instruments provides a PSpice model for the TL494. While PSpice models often work in LTspice, they require conversion. Download the .lib or .cir file from TI’s website, then use the .include directive in LTspice.

) . The output pulses alternate, ensuring a maximum individual duty cycle capped under per channel to guarantee safety margin. Adjusting Dead-Time Control (Pin 4) Selecting Output Modes : Right-click on any component

: Some models only support Push-Pull mode effectively; switching the OUTPUT CTRL pin to GND for parallel mode may not function correctly in all subcircuits.

Use OUT1 only in single-ended mode

) or a totem-pole driver stage (NPN/PNP pair) to see a switching waveform at these pins [6]. Pin 4 (Dead-Time Control) While PSpice models often work in LTspice, they

The is a widely used PWM controller, but it is not natively included in LTspice . To use it, you must download a third-party subcircuit model ( ) and its corresponding symbol file ( Key Performance & Simulation Issues

* TL494 Behavioral Model for LTspice .SUBCKT TL494 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 * Pins: 1(IN1+) 2(IN1-) 3(FB) 4(DT) 5(CT) 6(RT) 7(GND) 8(C1) 9(E1) 10(C2) 11(E2) 12(VCC) 13(OUT_CTRL) 14(VREF) 15(IN2+) 16(IN2-)

Tie Pin 13 to GND. Both output transistors switch simultaneously, allowing a maximum duty cycle near 90%.

+5V (REF) | [R_DTC] | DTC (Pin 4) +------[R_GND]----+ | v GND Oscillator Frequency (RT and CT)

: The DTC comparator adds a minimum off-time to the output pulses, preventing cross-conduction in power stages. The internal voltage on this comparator is nominally about 0.12V (or 0.1V, depending on the model version), which corresponds to a minimum dead time of about 3% to 5%. To adjust the dead time, you apply an external voltage between 0V and 3.3V to pin 4. Simply grounding this pin is not recommended unless you are sure you want the minimum possible dead time, as it can lead to shoot-through in your power stage.