IGBT vs. MOSFET: Key Differences

“IGBT” (Insulated Gate Bipolar Transistor) and “MOSFET” (Metal Oxide Semiconductor Field Effect Transistor) are two transistors used in many electrical devices.

MOSFETs are most commonly found in computer motherboards, where they act as high-efficiency switches to manage the flow of electricity. While IGBTs are most commonly found in industrial drives and cars, where they act as high-power switches to manage the flow of electricity necessary for driving water pumps or car’s powertrain.

Both MOSFETs and IGBTs are also found in inverters. For instance, an IGBT inverter is an inverter that is constructed with IGBT power modules to provide high voltage/power switching functions. It’s also called the “heart” of the electrified drive train for EVs/HEVs.

The IGBT inverter’s power module distributes and transforms direct current (DC) from the electric vehicle battery to alternating current (AC) for use in the electric motor that drives the vehicle’s propulsion system.

IGBT vs MOSFET Comparison

Both transistors allow electricity to flow through them more easily in one direction than in the other.

Difference 1: Working Principles of IGBTs and MOSFETs IGBT driver

An IGBT driver is basically a MOSFET device that controls a bipolar junction power transistor, whose power transistors are integrated on a single piece of silicon, while MOSFET, on the other hand, is the most common insulated gate FET, most often manufactured through controlled silicon oxidation.

MOSFETs work by electronically altering the width of the channel by varying the voltage on an electrode called the gate, which is positioned between the source and the drain and is insulated by silicon oxide. A MOSFET can operate in two modes: depletion mode and enhancement mode.

Difference 2: Review of Transistor Arrangements

IGBT drivers are commonly arranged in a “Parallel” pattern, meaning that each side is on its own separate transistor with both ends connected to an output (Ground). MOSFETs can be arranged in both Parallel and Series.

Difference 3: Gate Driver vs Gate Signal Generator

A  gate driver is a circuit used to drive (apply voltage to) the gate terminal of a transistor in order to make it conductive.

A Gate signal generator is much like a gate driver, except that instead of actually applying voltage to the gate terminal, it simply generates the gate voltage signal. IGBTs are typically driven by a gate driver, while MOSFETs can either use a Gate Signal Generator or a Gate Driver.

Difference 4: Structure

In an IGBT transistor, there is no insulator between the drain and source electrodes because it is formed with an NB (N-type) or a PN (P-type) junction that uses the surrounding substrate as an insulator.

In a MOSFET transistor, there is an insulating layer of oxide between the gate and source/drain electrodes because it is formed with a metal semiconductor junction.

Difference 5: Variations in Structure

IGBTs can be manufactured with different profiles (the cross sectional shape of the transistor) that affect how much current it can carry.

For example, IGBT are available in TO-247 and TO-220 packages, where TO-220 is better suited for higher currents than TO-247. MOSFETs may also be manufactured with different profiles, but they are normally packaged in standard surface-mount packages like SOT-23 and DFN.

Leave a Reply