the full form of igbt is insulated gate bipolar transistor.
it is constructed from the combining of both BJT and PMOSFET.
it has high input impedance and low on - state power loss .
it is free from second break down problem present in bjt...
it is also known as (MOSIGT), (COMFET)...
it is constructed virtualy in the same manner as a power
MOSFET.an IGBT has also thousand of basic structure cells
connected appropritely on a single chip of silicon.
it has a four substrate p,p+,n+,n-. respectively...
p+ substrate is called injection layer because it injects
holes into n- layer .n- layer is called drift region .
thickness of the n- layer determines the voltage blocking
capability of IGBT.
the p layer is called body of the IGBT.
WHERE IT IS USED : it is widely used in medium power
application such as DC and AC motors drives.
UPS SYSTEMS , RELAYS AND CONTACTORS.
In thyristor the gate is triggered the gate is losses its
control. ie if we remove the gate pulse after the thyristor
starts conducting it will not stop.
but in IGBT we can control the Gate. by applying reverse
voltage applied across it .
IGBT are widely used in medium power application such DC and
AC motor drive. IGBT is more expensive. The IGBT Of 1200 v,
500A rating 0.25 to 20 micro second turn off time with
operation frequency upto 50Khz are available.
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