1. Power Semiconductor Systems I
Author: Ales Havel
Phone number: 4287
Headquarters: E227
Web page:
Power Semiconductor Systems I

2. Presentation contents
Power semiconductor devices
Power diode
Thyristors
GTO thyristor
IGCT thyristor
MCT
Power transistors
Bipolar transistor (BJT)
MOSFET
IGBT
Main types of converters

3. Diode structure and symbol
Power diode
Single P-N junction creates a diode that has two terminals:
an anode (A) and a cathode (K).
Diode structure and symbol

4. Power diode
Steady State V-I Characteristic of a Diode

5. Power diode Dynamic parameters
Dynamic parameters relate to fast transition from ON to OFF states
Not only speed of transition between the two states is important, but also changes in the diode voltage and current during the transition should be taken into account.

6. Power diode
Transient V-I Characteristic of a Diode

7. Power diode Main requirements: reverse voltage Ur as high as possible
voltage drop UF as low as possible
turn-off speed as high as possible
Qrr (reverse recovery charge) as low as possible

8. Thyristor
Thyristor (SCR – Semiconductor Controlled Rectifier) is a controlled semiconductor device of 4-layer PNPN structure with 3 PN junctions.
Thyristor schematic symbol and structure

9. Thyristor
Steady-State V-I Characteristic of a Thyristor

10. Thyristor
Transient V-I Characteristics of a Thyristor

11. Thyristor Switching conditions: To turn-on: To turn-off:
UA = UD > 0 (forward blocking state)
Bring sufficiently high current IG into the gate
To turn-off:
The forward current has to stop flowing
A control electrode cannot effect thyristor turn-off
The IL current (latching current – min. value to turn on)
The IH current (holding current – min. value to stay open)

12. GTO thyristor
GTO thyristor (Gate Turn-Off thyristor) is a semiconductor device built on the same principle as traditional thyristor. The difference is in the case that the GTO could be turned of by the negative gate current.
GTO Thyristor schematic symbol and structure

13. MCT thyristor
MOS Controlled Thyristor (MCT) is voltage controlled fully controllable thyristor.
The MCT is similar in operation with GTO thyristor, but it has voltage controlled insulated gate.
It has two MOSFETs in its equivalent circuit. One is responsible for turn-on and the another is responsible for turn-off.

14. Transistors
The npn BJT is a three junction device that requires a continuous current flowing into the base region to supply enough charges to allow the junctions to conduct current.
Because the MOSFET and the IGBT are voltage controlled devices, they only require voltage on the gate to maintain conduction through the device.
The IGBT has one junction more than the MOSFET, and this junction allows higher blocking voltage and conductivity modulation, as described below, during conduction. This additional junction in the IGBT does limit switching frequency however.

15. BJT transistor
A Bipolar (Junction) Transistor (BJT) is a three-terminal electronic device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons and holes.
The BJT has three terminals, corresponding to the three layers of semiconductor – an emitter, a base, and a collector.
Schematic mark

16. BJT transistor Main principle of the BJT transistor Collector Base
Emitter
Switching the BJT transistor

17. BJT transistor
Static characteristics
Output
Transfer
Input
Reverse

18. MOSFET transistor
A Power MOSFET is a specific type of metal oxide semiconductor field-effect transistor that has been designed to handle large amounts of power.
N-Channel
P-Channel
Depletion mode
Enhancement mode

19. MOSFET transistor
Switching MOSFET

20. MOSFET transistor Static characteristic MOSFET Linear area
Saturation area

21. Symbol and equivalent circuit model of an IGBT
IGBT transistor
The Insulated Gate Bipolar Transistor (IGBT) is a minority- carrier device with high input impedance and large bipolar current-carrying capability.
Symbol and equivalent circuit model of an IGBT

22. IGBT tranzistor
Switching IGBT

23. IGBT tranzistor
Absolute maximum ratings

24. IGBT tranzistor
Electrical characteristic

25. IGBT
Thermal characteristic

26. IGBT
The IGBT is suitable for many applications in power electronics, especially in Pulse Width Modulated (PWM) servo and three- phase drives requiring high dynamic range control and low noise.
It also can be used in Uninterruptible Power Supplies (UPS), Switched-Mode Power Supplies (SMPS), and other power circuits requiring high switching repetition rates.
IGBT improves dynamic performance and efficiency and reduced the level of audible noise. It is equally suitable in resonant-mode converter circuits.
Optimized IGBT is available for both low conduction losses and low switching losses.

27. Comparison of power semiconductor devices

28. Power converters
A power semiconductor converter is an electrical device for converting electrical energy.

29. Thank You for your attention