Tl494 Circuit Diagram ((link)) May 2026
is a classic fixed-frequency Pulse Width Modulation (PWM) control integrated circuit (IC) that has served as the backbone for switch-mode power supplies (SMPS) for decades. Its enduring popularity stems from its comprehensive architecture, which integrates all the essential functions for PWM control—oscillator, error amplifiers, dead-time control, and output steering—into a single 16-pin package. The Core Architecture
By using the TL494 to drive a high-side MOSFET, you can create a highly efficient step-down converter. The chip ensures that even as your battery drains, the output voltage remains exactly where you set it. Pure Sine Wave Inverters tl494 circuit diagram
A standard TL494 circuit consists of the following key functional blocks: Oscillator (Pins 5 & 6): An external capacitor ( CTcap C sub cap T ) and resistor ( RTcap R sub cap T ) set the operating frequency. is a classic fixed-frequency Pulse Width Modulation (PWM)
- Duty Cycle Limitation: The TL494 can theoretically approach 100% duty cycle for Q1/Q2 in single-ended mode, but the boost formula is Vout = Vin / (1-Duty). For a 12V to 24V conversion, you need ~50% duty, which is easy.
- Soft-Start: Connect a capacitor (10uF) and resistor (100k) from Pin 4 to ground. The capacitor will charge slowly, allowing the duty cycle to ramp up gradually, preventing inrush current.
- Feedback: A voltage divider (R1=10k, R2=2.2k) feeds back the output voltage to Pin 1.
controller provides a complete suite of tools on a single chip. Duty Cycle Limitation: The TL494 can theoretically approach
Output Stage (Pins 8,9,11,10)
- Parallel mode (Pin13 = GND): Both transistors drive same inductor. Connect C1 & C2 to supply, E1 & E2 together to inductor.
- Push‑pull mode (Pin13 = REF): Alternating outputs for transformers.
- Each transistor can sink 500mA. For higher current, use external MOSFETs with gate drivers.
Whether you are building a simple PWM dimmer or a 500W push-pull inverter, the TL494’s circuit diagram follows the same fundamental architecture shown above. Start with the simple PWM generator on a breadboard, then move to a buck or boost converter.
- Vin to C1, R1, and Q1
- Vout to R2, C2, and L1
- TL494: