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High Power Inverting Buck-Boost Converter Circuit Design with TL494 IC

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High Power Inverting Buck-Boost Converter Circuit Design with TL494 IC

A high-power inverting buck-boost DC-DC converter circuit designed using the TL494 PWM controller and an N-channel MOSFET.

Originally published on CircuitDigest

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

10pcs - 220 ohm 1/4 W Resistor Set Rs. 39.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

This list includes a generic resistor set as a placeholder — it is not matched to the exact value or part number this circuit needs. The correct one is specified on the original source page linked above; check it before buying.

We don't carry yet: Microcontroller IC (DIP) / Chip
Transistors (BC547 / 2N2222 / TIP / MOSFET)
Inductors / Coils / Ferrite
LM35 / Analog Temp Sensor
Diodes (1N4007 / 1N4148 / Schottky / Zener)
Thyristor / SCR / Triac / Varistor / Fuse
Capacitors
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How It Works

This high-power inverting buck-boost DC-DC converter circuit utilizes a TL494 pulse-width modulation (PWM) controller IC to regulate an output voltage that is inverted in polarity and can be either higher or lower in magnitude than the input. The TL494 generates a precise switching frequency, governed by timing components like the 2.2nF capacitor, to drive the gate of an IRFZ44N N-channel power MOSFET. An LM358 operational amplifier, working alongside precision 1% resistors and a 10K trim-pot, provides feedback regulation and error amplification to maintain output stability under varying loads. When the IRFZ44N MOSFET switches on, energy is stored in the 220 uH inductor. Upon switching off, the inductor's magnetic field collapses, forcing current through the MBR20100CT power diode to charge the output capacitor network, which consists of 1000uF 25V and 63V capacitors. The R560 resistors function as current-sensing elements, allowing the control loop to monitor and limit current through the power stage. Power is cleanly interfaced to and from the custom-etched cladboard via two 5.08mm screw terminals, while the layout is designed using Eagle software.

Why Build This

Design and analyze advanced switched-mode power supplies (SMPS) capable of polarity inversion and flexible voltage conversion.

Implement closed-loop feedback control using operational amplifiers and dedicated pulse-width modulation (PWM) integrated circuits.

Gain practical engineering experience with high-power discrete components, thermal management, and printed circuit board design using Eagle.

Real-World Application

Power supplies, voltage regulation, battery-operated systems requiring both step-up and step-down DC conversion.

Skills You'll Learn

PWM controller configuration

switch-mode power supply design

closed-loop feedback regulation

MOSFET gate driving

PCB layout in Eagle

current-sensing techniques

Safety Precautions

While powering this circuit for the first time, use a Constant Current Power Supply to limit the current or a series of power resistors, as an incorrect PWM state can cause the MOSFET to short and burn down.

Technology Tags

DC-DC CONVERTER

TL494

PWM CONTROLLER

MOSFET

INDUCTOR

POWER ELECTRONICS

PCB DESIGN

LM358

DIFFERENTIAL AMPLIFIER

Frequently Asked Questions

Why is an inverting buck-boost converter used instead of a standard buck or boost regulator?

An inverting buck-boost converter provides a negative output voltage from a positive input voltage while offering the flexibility to either step up or step down the magnitude of that voltage.

What is the purpose of the TL494 IC in this circuit?

The TL494 acts as the dedicated pulse-width modulation (PWM) controller, generating the switching signals necessary to drive the IRFZ44N MOSFET and maintain stable voltage regulation.

Why must I use a constant current power supply or series resistors during initial testing?

An incorrect PWM state or short circuit can cause the MOSFET to fail catastrophically and draw excessive current, risking permanent damage to the components before the feedback loop stabilizes.

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This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-00574