What is an IGBT?

IGBT or Insulated Gate Bipolar Transistor is a type of power semiconductor device that combines the advantages of both the bipolar junction transistor (BJT) and the metal-oxide-semiconductor field-effect transistor (MOSFET). It is designed to handle high voltage and high current levels, making it suitable for power electronics applications.

IGBT is widely used in various power electronics systems, such as motor drives, uninterruptible power supplies (UPS), renewable energy inverters, electric vehicle controllers, and industrial machinery.

The structure of an IGBT consists of three main regions: the emitter, collector, and gate. The emitter and collector regions are made of heavily doped N-type and P-type semiconductor materials, respectively, forming a P-N-P structure similar to a BJT. The gate region is insulated from the semiconductor layers by a thin layer of oxide.

The operation of an IGBT involves three main stages:

• Forward Bias: When a positive voltage is applied to the gate terminal to the emitter, it creates an electric field that allows the flow of majority charge carriers (holes) from the emitter to the collector region. This stage is similar to the operation of a BJT in its active region.
• Saturation: Once the IGBT is in the forward-biased state, a positive voltage applied between the collector and emitter terminals allows a large current to flow through the device. In this stage, the IGBT acts as a low-resistance switch with minimal voltage drop across it, similar to a MOSFET.
• Reverse Bias: When the gate voltage is reduced or turned off, the IGBT enters a blocking state, preventing current flow between the collector and emitter regions. It acts as an open switch in this stage.

The IGBT offers several advantages, including high voltage and current handling capabilities, low on-state voltage drop, fast switching speed, and low power consumption. These features make it well-suited for high-power applications where efficient power conversion is required.

Key features of IGBT

• Low on-state voltage as compared to the BJT (bipolar junction transistor).
• Lower switching losses.
• Lower conduction losses.
• Ease of gate drive.
• Peak current capability.
• Ruggedness.
• Faster switching than BJT.

IGBTs can be classified into the following

• PT (Punch Through) – Punch-through IGBTs are those that have an n+ buffer layer. These IGBTs are used in inverter and chopper circuits and have symmetrical voltage blocking capabilities.
• NPT (Non-Punch Through) – Non-punch through IGBTs are those that don’t have an n+ buffer layer. They are used in rectifier applications and have symmetric voltage blocking capabilities.
• Symmetrical IGBTs - These IGBTs have equal forward and reverse breakdown voltage and are mostly used in AC circuits.
• Asymmetrical IGBTs – These IGBTs have a reverse breakdown voltage less than the forward breakdown voltage. They are commonly used in DC circuits.

Key Specifications of IGBT

• Collector-Emitter Voltage: It represents the voltage drop that occurs between the collector and the emitter terminals and is expressed in volts (V).
• Saturated Collector-Emitter Voltage: It represents the maximum voltage drop that occurs between the collector and emitter terminals and is expressed in volts (V).
• Gate Emitter Voltage: It represents the voltage drop that occurs between the gate and emitter terminals and is expressed in volts (V).
• DC collector Current: It represents the amplified output current that flows through the collector terminal of an IGBT and is expressed in Ampere (A).
• Peak Collector Current: It represents the maximum collector current that can be handled by the IGBT and is expressed in Ampere (A).
• DC Forward Current: It represents the current that the diode part inside an IGBT requires to conduct at room temperature conditions. It is expressed in Ampere (A).
• Peak Forward Current: It represents the maximum peak current that the diode inside an IGBT requires to conduct. It is expressed in Ampere (A).
• Gate Emitter Leakage Current: It refers to the leakage current that occurs due to the voltage drop between the gate and emitter terminals.
• Power dissipation (W): It represents power dissipated by the IGBT. It is equivalent to the product of collector current and collector-emitter voltage and is measured in Watts (W).

IGBTs from the leading manufacturers are listed on everything PE. You can use the filters on the left side to narrow down the list of products based on your requirements - type, number of transistors, package type, etc. Our parametric search tool will scan multiple manufacturer websites to identify IGBTs that meet your requirement. You can then download datasheets, request quotations via everything PE. Your inquiry will be routed to the manufacturer or their representative who will give you more information on the product.