Basic Structure; Working: Industrial Importance; Switching Characteristics

2. IGBT
Group Name:
GA-7
Group Leader: Azfar Rasool
12-EL-04
Group Members:
Musa Ali
M.Imran
Saba Nazeer
12-EL-37
12-EL-30
11-12EL-57

3. IGBT
(Insulated Gate Bipolar Transistor)

What does word stand for…..

Combination of BJT and MOSFET

Lab Symbol

Detailed description of symbol
{[(HOW)}

4. Construction and Basic Structure
Revert
the
polarities
and..
Check!

5. Changing to simplified circuit…

6. Working And Operation

Controlling factor: Gate Voltage

Called as voltage-controlled BJT

Input current zero at gate; as
insulated

Input is MOSFET characteristics

Output is BJT characteristics

Threshold Voltage

7. Working And Operation

npnp structure Thyristor

Parasitic transistor and resistence

no effect under normal operation

Max collector current

Parasitic transistor activates

Thus parasitic thyristor activates

Latch up condition dominates

i.e. IGBT will remain on

Cannot controlled by gate
voltage

8. How do IGBT LOOK like….
1RGT10075M12
5EMK80N
Internal Structure
Made in Italy
Made in China
A Dissectional view of
IGBT
• All of the IGBT’s related to any model do have the simplified
circuit drawn on it.

9. Importance & Advantages of IGBT
in Electrical & Electronics world

Combine features of MOSFET & BJT under single device

High current & High voltage Switching Applications, provides safe
gateway

Low on state voltage drop (MOSFET part) & High on state current
density; so smaller chip size & low cost manufacturing & production

Low voltage drop at input gate; so easily controlled compared to
thyristors & BJT’s.

High density current conduction provides excellent forward & reverse
blocking capabalites.

It can be used in every electronic and electrical circuits where high
switch repletion is need.

10. Applications of IGBT’s in Electrical &
Electronics World
Switch
Mode
Power Supplies
(SMPS)

Safe controlling to work with high
voltage or high current.

11. Uninterruptible Power
Supplies (UPS)

Old UPS gives audible irritating sound

IGBT use in UPS gives it high dynamic
range and low noise.

Ex: China company HOMAGE UPS

12. Pulse Width
Modulation (PWM)

Increase or decrease the
pulse width according to
requirement and desire

13. Three Phase Drivers

14. Switching Characteristics of IGBT’s

IGBT Switching Test Time Circuit

Switching Characteristics similar to Power
Mosfet

Difference is; tailing collector current due to
stored charge in N (negative) Drift region

Tail current increases turn off loss

Also increase the dead time between the
two devices in half-bridge circuit

Operates at -15V at gate to switch off

15.  Turn off speed limited of IGBT (How)
Lifetime stored charge or minority carriers in N(-ve) drift-region
Base is parasitic PNP transistor
No External means to sweep the minority carriers from N(-ve) drift region
To improve Switching time N(+ve) buffer layer helps

16. References:
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Abdus Sattar 1XYS Corporation
Text book: Electronic Device and
Circuits by Floyd

17. Thank You

18. Any Queries