Tl494 Ltspice 2021 <iOS>

Open LTspice, select File > New > Component, and create a new component file ( .asy ) using the provided .subckt text.

A boost converter presents a different set of simulation challenges.

The TL494 can achieve duty cycles up to nearly 100% (typically 96%) in single-ended mode, or 50% in push-pull mode, with dead time controlled by the DTC pin voltage.

Below is a functional SPICE model for the TL494 that can be used in LTspice. Copy the text below and save it as a file named TL494.sub in your LTspice library folder (typically C:\Users\<User>\Documents\LTspiceXVII\lib\sub ).

Output Collector/Emitter (Push-Pull or Parallel) VCC (Pin 12): Supply Voltage REF (Pin 14): 5V Reference Output Setting up the Test Circuit (e.g., Buck Converter): Place a Voltage Source (V1) for VCCcap V sub cap C cap C end-sub (e.g., 12V-30V). tl494 ltspice

For secondary-side synchronous rectification, some designers use two TL494 ICs — one for primary-side switching and one for secondary-side synchronous MOSFETs. These ICs can be synchronized by connecting the oscillator output of the master to the DTC pin of the slave. The datasheet discusses the synchronization start-up issues to be aware of.

The structural oscillator frequency is calculated using the standard formula:

: Create a 16-pin symbol ( .asy ) that matches the subcircuit's pin order: 1IN+ , 1IN- , FB , DTC , CT , RT , GND , C1 , E1 , E2 , C2 , VCC , OC , REF , 2IN- , 2IN+ [1, 3].

Use LTSpice behavioral elements to approximate PWM behavior when you only need functional simulation (not transistor-level fidelity). The simplified subcircuit below models: oscillator, ramp, error amp + comparator, and a PWM output (single-ended). This is for quick proof-of-concept control-loop and waveform checks. Open LTspice, select File > New > Component,

: If the model is a subcircuit, you can open the text file in LTspice, right-click the line, and select "Generate Symbol" Manual Placement : Alternatively, place the standard or a generic DIP-16 symbol and use the

You can verify PWM logic, oscillator frequency, and feedback loops without damaging components.

Probe the output pin (Pin 9 or 10) and the switching node. You should see a PWM square wave

When simulating this configuration, several specific issues arise: Below is a functional SPICE model for the

Available on GitHub's sunnyiisc Spice Collections or via customized fixes on MK Dynamics .

To use the in LTspice, you must use a third-party subcircuit because there is no native, official model provided by Linear Technology (Analog Devices) [2]. 1. The TL494 Subcircuit Code

(initial conditions) command to set voltages on capacitors like the timing capacitor ( cap C sub cap T