Tl494 Ltspice -

This is perhaps the most frequent complaint. Users report seeing a constant 12V at the emitter pins with no switching activity.

is essential for power electronics design, though it requires specific handling due to the lack of a native model in the standard LTspice library. MK Dynamics Availability of TL494 LTspice Models no official LTspice model

Power supply clamps VCC_IN 12 0 DC 0 E_VCC 100 0 VALUE V(12,9) R_VCC 100 0 1MEG

Remember the golden rules:

This modification adds an explicit node between the AND gate output and the collector, resolving compatibility issues with LTspice24’s stricter netlist parser.

7 = CT 8 = RT 9 = GND 10 = C1 11 = C2 12 = VCC

You can save the following code as TL494.sub and include it in your schematic. tl494 ltspice

PWM comparator: sawtooth (CT) vs COMP voltage

Below is a step-by-step walkthrough for option 1 (using a vendor model) and a compact alternative using a behavioral subcircuit for quick tests.

After downloading, extract the archive to the sym/ValVol folder. This is perhaps the most frequent complaint

Use OUT1 only in single-ended mode

Parameters (adjust as needed) .param Vref=5

Relax the solver tolerances by placing this SPICE directive on the canvas: .options cshunt=1p chgtol=1e-15 MK Dynamics Availability of TL494 LTspice Models no

Connect 1IN+ to a feedback voltage divider from the output, and 1IN- to a 2.5V reference (or to VREFcap V sub cap R cap E cap F end-sub via a resistor). Output Stage: Connect E1/E2 to drive a MOSFET gate. 4. Configuring Transient Analysis ( .tran ) To see the PWM in action, use a transient analysis.

.tran 0 5m 0 10n startup