Insulated gate bipolar transistor

WHAT IS INSULATED GATE BIPOLAR TRANSISTOR?

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Insulated Gate Bipolar Transistor is the abbreviation of IGBT and it is actually a semiconductor device. It has a wide range of bipolar current carrying capacity and has three terminals. It has CMOS input and bipolar output and most of the experts think that it is a voltage controlled bipolar device. Both BJT and MOSFET in monolithic form the design of IGBT can be done. Power circuits, pulse width modulation, interruptible power supply, power electronics, and much more are the applications of the insulated gate bipolar transistor. For reducing the audible noise level and for increasing the performance efficiency this device is used. Resonant mode converter circuits also uses it. For both low conduction and switching loss optimized insulated gate bipolar transistor is used.

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Insulated Gate Bipolar Transistor A 3 terminal semiconductor device with each terminal named as gate, emitter, and collector. Conductance path and gate terminal is associated with emitter and control terminal of the IGBT. The ratio between the input and output signal is called the calculation of the amplification attained. The sum of the gain is equal to the ratio of the output current to the input current named Beta for the conventional BJT. Mosfets or BJTS are the amplifier circuits where IGBT is mainly used. The combination of lower conduction loss in an amplifier circuit there is an occurrence of ideal solid state which is ideal in many uses of power electronics.

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Basic diagram of IGBT

In the N channel IGBT the Si section is almost the same as vertical power of MOSFET without P+ injecting layer. There is a share of metal oxide semiconductor with P­ wells though N+ regions. There are 4 layers in N+ layer and the one’s situation in the upper layer are called the source and the lower one’s are the drain.

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There are two types of IGBT  Non Punch Through IGBT  Punch Through IGBT If the IGBT is with N+ buffer layer then it is called NPT IGBT If the IGBT is without N+ buffer layer then it is called PT IGBT The working of an IGBT is faster than the power BJT and power MOSFET.

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Circuit of an IGBT

PNP, JFET, MOSFET, and NPN transistors are used for a simple IGBT driver circuit depending on its basic construction. The JFET transistor is used for connecting the collector of the NPN transistor to the base of the PNP transistor.

There is also a negative feedback loop in it. Among the neighboring IGBT cells the transistor denotes the structure of the current. Emitter, gate, and collector are the terminals of the IGBT shown.

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Characteristics of IGBT It is a voltage controlled device and therefore a small amount of voltage is enough on the gate terminal for continuing the conduction through the device unlike BJT where there is a continuous supply of base current for keeping it in saturation.

IGBT has only one directional switch, forward from collector to emitter. MOSFET is bidirectional.

The working principle of IGBT and MOSFET are the same but when the current flows through the device and the conducting channel offers resistance and the device is in the active state and current supplied is very small in IGBT whereas in MOSFET the current supply is higher. Thus the article has been completed and for further information join the institute of electrical engineering to make your career as an electrical engineer in this field.

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