Brief Overview of IGBT Semiconductors

IGBT semiconductors being together the functionalities of a Bipolar Junction Transistor (BJT) and a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). It has a control input with a MOS structure, while the bipolar power transistor acts as an output switch in the device. IGBTs are used to manufacture switching devices that can handle high currents and high voltage and can drive high-power applications that get a low power input.

IGBTs find application in a number of automotive and industrial applications and in home appliances and can tolerate spikes and overloads in current. In India, manufacturers offer IGTBs in various types that offer on-off delay, heat reduction, enhanced power density, as well as increased efficiency.

IGBTs that come with an n+ buffer layer are known as punch-through IGBTs, and IGBTs that do not have the layer are called non-punch through IGBTs. Based on their characteristics, punch-through IGBTs and non-punch-through IGBTs are also at times referred to as symmetrical and non-symmetrical IGBTs, of which the latter have equal forward and reverse breakdown voltage, and the former are mostly used in air conditioning circuits.

Since the IGBT is a voltage-controlled device, it requires only a small amount of voltage for the gate to remain in conduction state. Also, IGBT has unidirectional waves, and the current that flows in the circuit only moves in the forward direction, from the collector to the emitter. When voltage is applied to the gate pin, the IGBT starts conducting the current between the collector and the emitter; and when there is no voltage applied, the IGBT turns off and no current flows through the collector pin.

IGBTs are used in a wide range of applications such as AC and DC motor drives. IGBTs are also used in Switch Mode Power Supplies (SMPS), Unregulated Power Supply (UPS), traction motor controls, and inverters. IGBTs are also used as a switch between a single device to combine an isolated-gate FET and a bipolar power transistor.

IGBT offers advantages of both BJT and MOSFET, some of which are listed below:

The lower ON-state resistance and ability to switch high voltage at high frequencies without damaging the circuit are some of the features of the IGBT that make it ideal for driving applications with inductive loads like electromagnets, DC motors, and coil windings. There are several IGBT manufacturers in India, that offer different types of IGBTs that one may choose from based on their application.

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