MOSFET vs IGBT: Key Differences and When to Use Each

MOSFET and IGBT are both power semiconductor devices used for switching, but MOSFETs switch faster and are better for low voltage, high frequency applications, while IGBTs handle higher voltages and currents efficiently, making them ideal for high power, lower frequency uses.

Quick Comparison

Here is a quick side-by-side comparison of MOSFET and IGBT based on key factors.

Factor	MOSFET	IGBT
Switching Speed	Very fast (nanoseconds)	Slower (microseconds)
Voltage Range	Low to medium (up to ~250V)	Medium to high (up to several kV)
Current Handling	Moderate	High
Conduction Loss	Lower at low voltage	Lower at high voltage
Control Type	Voltage controlled	Voltage controlled but with bipolar conduction
Typical Applications	High frequency switching, low voltage power supplies	High power motor drives, inverters, and industrial equipment

Key Differences

MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are voltage-controlled devices that switch very quickly and have low on-resistance at low voltages. They are ideal for applications requiring fast switching and efficiency at lower voltages, such as computer power supplies and RF amplifiers.

IGBTs (Insulated Gate Bipolar Transistors) combine the easy gate drive of MOSFETs with the high current and voltage handling of bipolar transistors. They switch slower than MOSFETs but can handle much higher voltages and currents, making them suitable for industrial motor drives, electric vehicles, and power inverters.

In summary, MOSFETs excel in speed and efficiency at low voltages, while IGBTs are preferred for high power and voltage applications despite slower switching speeds.

Code Comparison

Example: Controlling a simple switch using a MOSFET in an Arduino circuit.

arduino

const int mosfetPin = 9;

void setup() {
  pinMode(mosfetPin, OUTPUT);
}

void loop() {
  digitalWrite(mosfetPin, HIGH); // Turn MOSFET ON
  delay(1000);                   // Wait 1 second
  digitalWrite(mosfetPin, LOW);  // Turn MOSFET OFF
  delay(1000);                   // Wait 1 second
}

Output

The MOSFET switches ON and OFF every second, controlling the connected load.

IGBT Equivalent

Example: Controlling a similar switch using an IGBT in an Arduino circuit.

arduino

const int igbtPin = 9;

void setup() {
  pinMode(igbtPin, OUTPUT);
}

void loop() {
  digitalWrite(igbtPin, HIGH); // Turn IGBT ON
  delay(1000);                 // Wait 1 second
  digitalWrite(igbtPin, LOW);  // Turn IGBT OFF
  delay(1000);                 // Wait 1 second
}

Output

The IGBT switches ON and OFF every second, controlling the connected load.

When to Use Which

Choose MOSFET when you need very fast switching at low to medium voltages, such as in switching power supplies, audio amplifiers, or high-frequency circuits.

Choose IGBT when working with high voltages and currents, especially in industrial motor drives, electric vehicles, or power inverters where switching speed is less critical than power handling.

Key Takeaways

MOSFETs switch faster and are best for low voltage, high frequency applications.

IGBTs handle higher voltages and currents but switch slower than MOSFETs.

Use MOSFETs for efficient low power switching and IGBTs for high power industrial uses.

Both devices are voltage controlled but differ in conduction and switching characteristics.

Choosing depends on voltage, current, switching speed, and application requirements.