| File | Purpose | |------|---------| | TL494.sub | Subcircuit definition (Spice netlist) | | TL494.asy | LTspice schematic symbol | | TL494_test.asc | Example test circuit |
Map the pins according to the standard TL494 pinout: Pins 1 & 2: Error Amp 1 Inputs ( Invcap I n v Pin 3: Feedback ( Feedbackcap F e e d b a c k Pin 4: Dead-Time Control ( DTCcap D cap T cap C Pin 5 & 6: Oscillator CTcap C sub cap T RTcap R sub cap T Pin 7: Ground ( GNDcap G cap N cap D Pins 8 & 9: Collector & Emitter for Output 1 Pins 10 & 11: Emitter & Collector for Output 2 Pin 12: Supply Voltage ( VCCcap V sub cap C cap C end-sub Pin 13: Output Control (Common Emitter/Push-Pull) Pin 14: Reference Voltage ( VREFcap V sub cap R cap E cap F end-sub Pins 15 & 16: Error Amp 2 Inputs Constructing a Basic TL494 Buck Converter Simulation tl494 ltspice
: An interesting observation from the Qorvo tech forum shows that the same TL494 SPICE subcircuit can produce different simulation results when run in LTspice versus QSPICE, another free simulator. This serves as a reminder that simulation results are not absolute truth but are dependent on the software’s underlying algorithms. Always cross-reference your simulation results with datasheet specifications and breadboard prototypes. | File | Purpose | |------|---------| | TL494
* Oscillator Vramp OSC 0 PULSE(0 3 0 1u 1u 10u 20u) * PWM comparator (feedback voltage vs ramp) Bpwm OUT 0 V=if(V(feedback) > V(OSC), 5, 0) * Dead-time control Bdt OUTD 0 V=if(V(OUT)>0.5 & V(dtc)<1, 5, 0) * Oscillator Vramp OSC 0 PULSE(0 3 0
: Used for voltage and current regulation.