Introduction

Electronic devices are ubiquitous in our lives, and most of them require electrical energy conversion. To meet different application needs, suppliers have developed many kinds of switching devices. The trend in power electronics today is to use semiconductor switching devices for rectification, switching and control of voltage and current. MOSFETs and IGBTs are two common solutions that are widely used. Therefore, it is very important to know how to distinguish them. Although they are both voltage controlled devices, they differ in many ways. By reading this article, the reader can get an initial understanding of how these two devices work and the differences between them.

Difference Between IGBT and MOSFET (IGBT vs MOSFET)

 

 

Type

IGBT: An IGBT is a hybrid device of a bipolar junction transistor (BJT) and a metal-oxide-semiconductor field-effect transistor (MOSFET). It combines the advantages of two types of devices, high input resistance and low switching losses (MOSFET), and high current handling capability (BJT).

MOSFET: A MOSFET is a field-effect transistor based on a metal-oxide-semiconductor structure. It controls the current in the channel by changing the gate voltage, thus realizing the switching function.

 

Terminal

IGBT: An IGBT has three terminals: Emitter (E), Collector (C) and Gate (G).

MOSFET: A MOSFET has three terminals: Gate (G), Source (S) and Drain (D).

 

PN Junction

IGBT: The structure of the IGBT contains a PN junction. Its structure is similar to a bipolar junction transistor (BJT), with an input stage of NPN structure and an output stage of PNP structure.

MOSFET: There is no PN junction in the structure of MOSFET. It mainly relies on changes in the gate voltage to control the current flow in the channel.

 

Application

IGBT: Due to its high current handling capability, IGBTs are often used in high power applications such as motor drives, inverters and grid applications.

MOSFET: MOSFETs are suitable for low and medium power applications such as power management, electronic switches and amplifiers.

 

Voltage and Power Handling Capacity

IGBT: IGBTs are generally capable of higher voltages and powers. They are rated for thousands of volts and capable of handling hundreds of amps.

MOSFET: MOSFETs have a lower voltage rating, usually between tens of volts and hundreds of volts, and are capable of handling tens of amperes of current.

 

Working Frequency

IGBT: IGBTs are usually used in low or medium frequency applications and have slower switching speeds. They work well in the hundreds of Hertz to thousands of Hertz range.

MOSFET: MOSFETs switch very fast and are therefore suitable for high frequency applications. They are capable of operating at frequencies of several megahertz.

 

Forward Voltage Drop

IGBT: IGBT has a large forward voltage drop, usually between 1V and 2V.

MOSFET: MOSFETs have a small forward voltage drop, usually between a few hundred millivolts and 1V.

 

Off Time

IGBT: The turn-off time of IGBT is longer, usually between several microseconds and hundreds of microseconds.

MOSFET: The MOSFET has a short turn-off time, usually between a few nanoseconds and tens of nanoseconds.

 

Switching Speed

IGBT: The switching speed of IGBT is relatively slow, usually between tens of nanoseconds and hundreds of nanoseconds.

MOSFET: MOSFETs switch very fast, usually between a few nanoseconds and tens of nanoseconds.

 

Transient Voltage and Current Handling Capability

IGBT: Due to the bipolar transistor characteristics in its structure, IGBT has better handling ability for transient voltage and current. They are highly resistant to transient overvoltages and overcurrents.

MOSFET: MOSFET is relatively weak in handling transient voltage and current. MOSFETs are susceptible to damage when subjected to transient overvoltages or overcurrents.

 

Saturation Voltage

IGBT: The saturation voltage of IGBT is relatively high, usually between 1V and 2V.

MOSFET: The saturation voltage of the MOSFET is low, usually below a few hundred millivolts.

 

Cost

IGBT: Due to its complex structure and high power handling capacity, the cost of IGBT is relatively high.

MOSFET: MOSFETs are less costly due to their relatively simple construction and are suitable for low power applications.

 

Application

IGBT: IGBTs are widely used in motor drives, inverters, power grid applications, electric vehicles and high-power power supply equipment.

MOSFET: MOSFET is suitable for low-power to medium-power circuits such as power management, electronic switches, amplifiers, and electronic computers.

 

Conduction Loss

IGBT: Due to its structure and high on-resistance, IGBT has a large conduction loss.

MOSFET: MOSFETs have lower conduction losses because they have lower on-resistance.

 

Switching Loss

IGBT: IGBT has low switching losses due to its structure and long off time.

MOSFET: MOSFETs have higher switching losses because of their shorter off-time and faster switching speed.

 

Structure & Working Principle

IGBT: The structure of IGBT combines the characteristics of MOSFET and BJT. It consists of a MOSFET controlling the conduction state of a BJT. The MOSFET controls the switching function of the IGBT, while the BJT is responsible for carrying the current.

MOSFET: A MOSFET controls the current flow between source and drain through a change in gate voltage. The charge in the channel is controlled by the gate electric field, which regulates the current flow.

 

S.O.A. (Safe Operating Area)

IGBT: The S.O.A. range of IGBTs is relatively large because of their ability to withstand high currents and voltages.

MOSFET: MOSFETs have a smaller S.O.A. range because of their lower voltage and power handling capabilities.

 

Drive Method

IGBT: IGBT usually requires higher drive voltage and current because of the characteristics of BJT and MOSFET included in its structure.

MOSFETs: MOSFETs generally require lower drive voltages and currents because they rely primarily on changes in gate voltage for control.

 

Drive Circuit

IGBT: Due to its high driving voltage and current requirements, the driving circuit of IGBT is relatively complicated.

MOSFET: The drive circuit for MOSFETs is relatively simple because they generally require low drive voltage and current.

 

Parasitic Diode

IGBT: IGBT has a forward biased parasitic diode inside. This diode acts as a protection during switching operation, but an additional anti-parallel diode may be required in some applications.

MOSFET: There is no parasitic diode inside the MOSFET. Therefore, an additional anti-parallel diode is required to protect the MOSFET from reverse voltage during switching operation.

 

Read More:

Difference Between BJT, MOSFET and IGBT: BJT vs MOSFET vs IGBT

IGCT vs. IGBT: What Are the Difference

IGBT vs GTO: Difference Between IGBT and GTO

IGBT Structure, Characteristics and Working Principle
Application of IGBT and IGBT Application Examples
IGBT Symbol Diagram, Characteristics, Circuit
Global IGBT Shortage: Cause & Future Outlook
IGBT Rectifier: All You Want to Know
IGBT Types: Understanding the Basics
How to Test an IGBT with A Multimeter
Difference Between IGBT and MOSFET (IGBT vs MOSFET)
What is the Advantage of IGBT

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