1. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-1 Chapter 2 Overview of Power Semiconductor Devices Introduction Diodes Thyristors Ideal switches Bipolar transistors MOSFETs MOS-Controlled Thyristors Comparison of controllable switches

2. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-2

3. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-3

4. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-4

5. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-5 Thyristors Semi-controlled device Latches ON by a gate-current pulse if forward biased Turns-off if current tries to reverse

6. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-6

7. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-7 Thyristor in a Simple Circuit For successful turn-off, reverse voltage required for an interval greater than the turn-off interval

8. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-8 Generic Switch Symbol Idealized switch symbol When on, current can flow only in the direction of the arrow Instantaneous switching from one state to the other Zero voltage drop in on-state Infinite voltage and current handling capabilities

9. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-9 Switching Characteristics (linearized) Switching Power Loss is proportional to: switching frequency turn-on and turn-off times

10. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-10 Small leakage current in off state Small on state voltage Short turn-on and turn-off Large forward and reverse voltage High on state current rating Positive temperature coefficient Small control power required to switch Capability to survive rated voltage and rated current simultaneously Switch: ideal characteristics

11. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-11 Bipolar Junction Transistors (BJT) #1 Used commonly in the past Now used in specific applications Replaced by MOSFETs and IGBTs

12. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-12 Bipolar Junction Transistors (BJT) #2

13. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-13 Bipolar Junction Transistors (BJT) #3

14. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-14 Various Configurations of BJTs

15. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-15 Conclusions BJTs

16. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-16 MOSFETs #1 Easy to control by the gate Optimal for low-voltage operation at high switching frequencies On-state resistance a concern at higher voltage ratings

17. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-17 MOSFETs #2

18. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-18

19. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-19

20. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-20 IGBT

21. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-21

22. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-22 Conclusions IGBT

23. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-23 Gate-Turn-Off Thyristors (GTO) Slow switching speeds Used at very high power levels Require elaborate gate control circuitry

24. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-24 MOS CONTROLLED THYRISTORS (MCT)

25. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-25

26. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-26 Comparison of Controllable Switches

27. Electrónica de Potência © 2008 José Bastos Chapter 2 Power Semiconductor Switches: An Overview 2-27 Summary of Device Capabilities