TL494 Current-Mode PWM Controller working and Pinout
In this article we will learn how to make TL494 Current-Mode PWM Controller working and Pinout.
In the last post we will learn how to make LM317 Adjustable voltage regulator circuit Pinout and Working. You can visit our website,
I hope you appreciate my work, let’s discuss about today’s project.
What is TL-494?
The TL-494 is an integrated circuit (IC) used in the control of pulse-width modulation (PWM) signals. It’s commonly employed in various power supply applications, especially in switch-mode power supplies (SMPS) and motor control circuits. This chip serves as a pulse-width modulator or controller, offering precise control over the duty cycle of the output waveform.
- PWM Generation:
The TL494 generates adjustable pulse widths, making it suitable for controlling power switches in SMPS.
- Error Amplifier:
It includes an error amplifier that compares a reference voltage with a feedback signal, enabling regulation of the output.
- Output Drivers:
These drivers help control external power transistors or FETs, regulating the power supply output.
- Soft-Start Functionality:
It often incorporates a soft-start circuit to prevent sudden high currents during startup.
- Protection Circuits:
Some versions of the TL494 have built-in protection circuits for over current and overvoltage situations, ensuring safety in the circuit.
TL494 Current-Mode PWM Controller Circuit Diagram:
The IC contains an internal oscillator that generates a triangular waveform. This waveform serves as a timing reference for the PWM signal.
The triangular waveform from the oscillator is compared with the error signal from the error amplifier. This comparison determines the width of the pulses in the PWM signal.
- Output Drivers:
The TL-494 includes output drivers that control external power transistors or FETs. These external components switch power to the output circuit based on the PWM signal generated by the IC.
- Feedback and Regulation:
Through the error amplifier and feedback loop, the TL494 regulates the output voltage by adjusting the duty cycle of the PWM signal. By modifying the duty cycle, it controls the average voltage applied to the load.
- Protection Features:
Some versions of the TL-494 incorporate protection features such as over current and overvoltage protection. These features help safeguard the circuit and connected devices from potential damage.
- Additional Functions:
The IC might also include functions like soft-start circuits to manage the startup sequence, preventing sudden high currents that could damage components.