The document discusses IGBT (Insulated Gate Bipolar Transistor), a three-terminal semiconductor switching device used for fast switching with high efficiency. It has three terminals - collector, emitter, and gate. The gate terminal is insulated from the semiconductor layers. IGBT is constructed of four layered semiconductors sandwiched together. IGBT characteristics include initially blocking current flow until the gate voltage exceeds the threshold voltage, after which collector current increases with gate voltage. The output characteristics also have three stages - cutoff, small leakage current, and active regions depending on the gate voltage. IGBT is mainly used in power applications due to advantages over BJTs and MOSFETs like lower on-res

1. IGBT AND THEIR CHARACTERISTICS
Name: Muhammad Moin
MUET Jamshoro

2. IGBT
 IGBT is the short form of Insulated Gate Bipolar Transistor. It is a
three-terminal semiconductor switching device that can be used for
fast switching with high efficiency in many types of electronic devices.
These devices are mostly used in amplifiers for switching/processing
complex wave patters with pulse width modulation (PWM). The
typical symbol of IGBT along with its image is shown below.

3. WE CAN SEE THAT THE INSULATED GATE BIPOLAR TRANSISTOR IS A
THREE TERMINAL, TRANS CONDUCTANCE DEVICE THAT COMBINES AN
INSULATED GATE N-CHANNEL MOSFET INPUT WITH A PNP BIPOLAR
TRANSISTOR OUTPUT CONNECTED IN A TYPE OF DARLINGTON
CONFIGURATION.
AS A RESULT THE TERMINALS ARE LABELED
AS: COLLECTOR, EMITTER AND GATE. TWO OF ITS TERMINALS (C-E)
ARE ASSOCIATED WITH THE CONDUCTANCE PATH WHICH PASSES
CURRENT, WHILE ITS THIRD TERMINAL (G) CONTROLS THE DEVICE.

4.  IGBT has three terminals attached to three different metal layers, the
metal layer of the gate terminal is insulated from the semiconductors
by a layer of silicon dioxide (SIO2). IGBT is constructed with 4 layers
of semiconductor sandwiched together. The layer closer to the
collector is the p+ substrate layer above that is the n- layer, another p
layer is kept closer to the emitter and inside the p layer, we have the n+
layers. The junction between the p+ layer and n- layer is called the
junction J2 and the junction between the n- layer and the p layer is
called the junction J1. The structure of IGBT is shown in the figure
below.

5. VI CHARACTERISTICS OF IGBT
 The input characteristics of IGBT can be understood from the graph
below. Initially, when no voltage is applied to the gate pin the IGBT
is in turn off condition and no current flows through the collector
pin. When the voltage applied to the gate pin exceeds the threshold
voltage, the IGBT starts conducting and the collector current
IG starts to flow between the collector and emitter terminals. The
collector current increases with respect to the gate voltage as shown
in the graph below.

6.  The output characteristics of IGBT have three stages,
initially, when the Gate Voltage VGE is zero the device is in
the off state, this is called the cutoff region. When VGE is
increased and if it is less than the threshold voltage then there
will be a small leakage current flowing through the device,
but the device will still be in the cutoff region. When the
VGE is increased beyond the threshold voltage the device
goes into the active region and the current starts flowing
through the device. The flow of current will increases with an
increase in the voltage VGE as shown in the graph above.

7. APPLICATIONS OF IGBT:
 IGBT is mainly used in Power related applications.
Standard power BJT’s have very slow response
properties whereas MOSFET is suitable for fast
switching application, but MOSFET is a costly choice
where higher current rating is required. IGBT is suitable
for replacing power BJTs and Power MOSFETs.
 Also, IGBT offers lower ‘ON’ resistance compared with
BJTs and due to this property the IGBT is thermal
efficient in high power related application.
 IGBT applications are vast in electronics field. Due
to low on resistance, Very high current rating, high
switching speed, zero gate drive, IGBTs are used in High
power motor control, Inverters, switched mode power
supply with high frequency converting areas.

8. THANKS