What is the Difference Between IGBT and MOSFET?

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IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal Oxide Semiconductor Field Effect Transistor) are both voltage-controlled devices used in electronic circuits. However, they have different characteristics and are suitable for different applications. Here are some key differences between IGBT and MOSFET:

  1. Suitability: IGBTs are suitable for medium to high current conduction and controlling, while MOSFETs are suitable for low power DC applications like power supplies.
  2. Switching Frequency: IGBTs are commonly used at a switching frequency lower than 20 kHz, while MOSFETs are ideal for switching power supplies and other applications that operate at about 100 kHz and at low current density.
  3. On-state Resistance: Low voltage MOSFETs have a much lower 'ON' resistance than IGBTs, making MOSFETs more suitable for applications that require low power loss.
  4. On-state Voltage: In the low-current region, MOSFETs exhibit a lower on-state voltage than IGBTs. However, in the high-current region, IGBTs exhibit lower on-state voltage than MOSFETs, particularly at high temperatures.
  5. Drive Circuit: IGBTs require a more complicated drive circuit compared to MOSFETs, which have a relatively simple drive circuit.
  6. Parasitic Diode: MOSFETs have a parasitic body diode, while IGBTs may have a parasitic diode only in RC-IGBTs.

In summary, IGBTs are more suitable for high power AC applications, such as inverter circuits, while MOSFETs are more suitable for low power DC applications, like power supplies. The choice between IGBT and MOSFET depends on factors such as switching frequency, on-state resistance, on-state voltage, and drive circuit complexity.

Comparative Table: IGBT vs MOSFET

Here is a table comparing the differences between IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal Oxide Semiconductor Field Effect Transistor):

Parameter IGBT MOSFET
Full Form Insulated Gate Bipolar Transistor Metal Oxide Semiconductor Field Effect Transistor
Definition Three-terminal semiconductor switching device used in electronic circuits Four-terminal semiconductor switching device used in switching and amplifier applications
Terminal Three terminals: emitter (E), gate (G), and collector (C) Four terminals: source (S), drain (D), gate (G) and body (or substrate)
Gate Drive Circuit Combined features of BJT and MOSFET Relatively simple switching applications
On-State Voltage Lower on-state voltage than MOSFET in high-current region, particularly at high temperatures Lower on-state voltage in low-current region
Switching Time Faster than bipolar transistors and slower than MOSFETs Ultra-high speed (Unipolar device)
Parasitic Diode Present only in RC-IGBTs Present (body diode)
Switching Frequency Commonly used at a switching frequency lower than 20 kHz due to higher switching loss than unipolar MOSFETs Generally higher switching frequencies
Power Application Preferred in high-power applications due to lower conduction losses and higher efficiency Typically preferred for lower voltage and lower power applications

Both IGBTs and MOSFETs are used for switching applications in power electronics, but they have different characteristics and performance. IGBTs are known for their lower conduction losses and higher efficiency in high-power applications, while MOSFETs are preferred for lower voltage and lower power applications due to their higher switching frequencies and lower power dissipation.