INTERRUPTORES, TIRISTORES EN ELECTRONICA

INTERRUPTORES

1. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-1
Chapter 2 Overview of Power
Semiconductor Devices

2. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-2
Diodes
•On and off states controlled by the power circuit

3. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-3
Diode Turn-Off
•Fast-recovery diodes have a small reverse-recovery time

4. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-4
Thyristors
•Semi-controlled device
•Latches ON by a gate-current pulse if forward biased
•Turns-off if current tries to reverse

5. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-5
Thyristor in a Simple Circuit
•For successful turn-off, reverse voltage required
for an interval greater than the turn-off interval

6. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-6
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

7. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-7
Switching Characteristics (linearized)
Switching Power Loss is
proportional to:
•switching frequency
•turn-on and turn-off times

8. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-8
Bipolar Junction Transistors (BJT)
•Used commonly in the past
•Now used in specific applications
•Replaced by MOSFETs and IGBTs

9. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-9
Various Configurations of BJTs

10. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-10
MOSFETs
•Easy to control by the gate
•Optimal for low-voltage operation at high switching frequencies
•On-state resistance a concern at higher voltage ratings

11. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-11
Gate-Turn-Off Thyristors (GTO)
•Slow switching speeds
•Used at very high power levels
•Require elaborate gate control circuitry

12. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-12
GTO Turn-Off
•Need a turn-off snubber

13. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-13
IGBT

14. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-14
MCT

15. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-15
Comparison of Controllable Switches

16. Copyright © 2003
by John Wiley & Sons, Inc.
Chapter 2 Power Semiconductor
Switches: An Overview
2-16
Summary of Device Capabilities