Elektronika daya kuliah ke 2 Power Semiconductor Switches

Elektronika daya kuliah ke 2

1. Power Semiconductor Switches
Pekik Argo Dahono

2. Power Semiconductor Switches
•Diodes (Uncontrolled switches)
•Thyristors (Controllable at turn-on but
uncontrolled at turn-off or commonly called
as latched devices). Triac is under the same
category.
•BJT, MOSFET, IGBT, GTO, MCT etc. are
fully controllable switches.

3. Power Diodes

A
K
P
N
A
K
P
N
N
A
K
AK
v
AK
i
AK
v
AK
i

4. Reverse Recovery Problems
dE FD
S
oI
rrt
SI
oI
FD
I
FDV

5. Power diodes
Diodes are classified as:
-general purpose or line-frequency diodes
-Fast recovery diodes
-Schottky diodes

6. Schottky Diode
•The schottky diode has a smaller voltage
drop compared to conventional diodes
(about 0.3 V).
•The schottky diode has a smaller voltage
breakdown than conventional diodes (less
than 200 V).

7. Sample of diodes

8. Thyristor

P
P
N
N
K
G
A
Ai
Holding
current I
G
3
I
G
2
I
G
1
I
G
= 0
Forward
breakover
voltage
Forward
leakage
Forward
conduction
Reverse
leakage
Avalanche
breakdown
AKv
A
i
Gate
Anode
Cathode

9. Thyristor Model
GI
1Q
2Q
1BI
1EA
II
2CI 1C
I
2B
I
2EI
 
21
02012
02222
01111
1 








CCG
A
CEC
CEC
III
I
III
III

10. Thyristor Classification
•Phase control thyristors
•Inverter-grade or fast-type thyristors
•Light activated thyristors
•Reverse conducting thyristors

11. Thyristor Features
•Latching devices
•Double carrier devices
•Having forward and reverse blocking
capabilities
•Very high gain (I
A/I
g)
•Low on-state voltage
•Can be protected by fuse

12. Sample of thyristors

13. Thyristor Modules

14. Switching Characteristics

dont
ri
t
fvt dofft
rvt
fi
t
signal
Gate
current
& voltage
Transistor
power
Transistor
T
v
Ti
dE
o
I
sonodson tIEW
2
1

soffodsoff tIEW
2
1

cdP
fvrison ttt 
firvsoff ttt 
dE
Ti
Tv
oI

15. Desired Switch Characteristics
•Small leakage current in the off state
•Small on-state voltage
•Short turn-on and turn-off times
•Large forward and reverse blocking voltage capabilities
•High on-state current rating
•Positive temperature coefficient of on-state resistance
•Small control power
•Wide Safe Operating Area
•Large dv/dt and di/dt ratings

16. Losses
Switching losses :
Conduction losses :

 
soffsonsods ttfIEP 
2
1
s
ON
ooncd
T
T
IVP
f
s
is switching frequency.
T
s is switching period.

17. Bipolar Junction Transistor

N
P
N
C
E
B
B
C
E
C
i
Bi
CE
v
Ci
0
1

B
i
2Bi
3B
i
4B
i
5B
i
12345 BBBBB
iiiii 
CE
v
Ci

18. VI characteristics of BJT
CE
v
C
I
0
0
BI
1BI
2B
I
3BI
4B
I
5B
I
0
BI
SUSBV
0CB
BV
breakdown Second
breakdown
Primary
saturation-Quasi
saturation-Hard

19. Operating region
•Hard-saturation provides low voltage-drop but a
large storage time (turn-off time)
•Quasi-saturation provides high voltage-drop but a
small storage time.
•Second breakdown must be avoided by using a
snubber and proper base current control.
•Negative base current results in higher voltage
breakdown.

20. Antisaturation circuit

21. BJT Features
•Current controlled devices
•Double carrier devices
•No reverse blocking capability
•Low gain (I
c/I
b)
•Low on-state voltage
•Can not be protected by fuse
•Second breakdown problem

22. Darlington Configuration
EB
2
R
1
R
2
T
2
T
1
B
1
C

23. MOSFET

Di
0
1

GS
v
2GS
v
3GS
v
4GS
v
5GS
v
12345 GSGSGSGSGS vvvvv 
DSv
Di
G
D
S
Di
DS
v
Gate
SiO
2
Source
N+N+
N+
N-
P P
Drain
D-MOS structure

24. MOSFET Features
•Voltage controlled devices
•Single carrier devices
•High on-state voltage
•Very high gain
•No reverse blocking capability
•No second breakdown problem
•Can not be protected by fuse

25. Integrated Power MOSFET
S1
Top Drive &
Overcurrent
Protection
S2
Bot Drive &
Overcurrent
Protection
Timing
Control Logic
& Phase Status
Output Voltage
Detector
Level Shifting
D
f
C
f
G1
I
s 1
R
S
R
S
G2
I
s 2
V
DD
Top
Bottom
Fault
V
OUT
+V
DC

26. Gate-Turn-Off (GTO) Thyristor

Gate
Anode
Cathode
Forward
leakage
Forward
conduction
Reverse
leakage
Avalanche
breakdown
AK
v
A
i
condition
Blocking

27. GTO switching characteristic

I
GR
(b)
V
d
Anode
current
Anode
voltage
Tail
current
Spike
voltage
I
A
0
Time

28. GTO Features
•Controllable at turn-on and turn-off
•High-voltage capability
•Can be designed with reverse blocking
capabilty
•Low gain at turn-off
•Low on-state voltage
•High turn-off losses

29. Insulated Gate Bipolar Transistors (IGBTs)

C
E
Ci
G
CEv
C
i
12345 GEGEGEGEGE vvvvv 
0
1

GE
v
2GE
v
3GEv
4GEv
5GEv
GATE
COLLECTOR
P
+
N
-
N
+
N
+
P
+
PP
R
N
-
(MOD)
EMITTER
-
+

30. IGBT Features
•Combining the advantages of BJT and
MOSFET
•No reverse blocking capability
•No second breakdown
•High gain at turn on and turn off

31. Other Switching Devices
•Static Induction Transistor and Static Induction
Thyristor. The main problems are normally-on and
high conduction loss. The advantage is that the
speed is very high.
•MOS Controlled Thyristor. Combining the
advantages of MOSFET and Thyristor. Still under
development.
•IGCT (Integrated Gate Controlled Thyristor). This
is further development of GTOs.

32. Switching Device Development

THYRISTOR
GTO
BPT
10
-1
10
-1
10
0
10
1
10
2
10
4
10
1
10
2
10
3
10
4
P


(
k
V
A
)
f (kHz)
1 9 8 0
H
IG
H
P
O
W
E
R
E
A
S
Y
D
R
IV
E
H
IG
H
FR
E
Q
U
E
N
C
Y
1 9 9 0
THYRISTOR
10
3
10
4
10
-1
10
-1
10
0
10
1
10
2
10
4
10
2
P


(
k
V
A
)
f (kHz)
10
5
10
1
GTO
BPT
MOS
IGBT
2 0 0 0
10
-1
10
-1
10
0
10
1
10
2
10
4
OPERATION FREQUENCY f (kHz)
10
5
MOS
10
6
10
3
10
4
10
2
C
O
N
T
R
O
L
L
A
B
L
E

P
O
W
E
R





P


(
k
V
A
)
10
1
10
5
BPT
IGBT
MCT
SI Thy
GTO
THYRISTOR
GTO : GATE TURN-OFF THYRISTOR
MCT : MOS CONTROLLED THYRISTOR
SI Thy : STATIC INDUCTION THYRISTOR
BPT : BIPOLAR POWER TRANSISTOR
IGBT : INSULATED GATE BIPOLAR TRANSISTOR

33. Reverse Conducting and
Reverse Blocking Switching Devices
conducting Reverse blocking Reverse

34. Bidirectional Switches

35. Switching devices
Switch Ideal
switch eduncontroll onalUnidirecti
switch lledsemicontro onalUnidirecti
switch controlledfully conducting Reverse
switch lledsemicontro nalBidirectio
switch controlled fully blocking Reverse
switch controlled fully nalBidirectio
switch controlledfully conducting Reverse

36. Properties and Rating of
Semiconductor Power Switches
Switch Control
signal
Control
characteristic
Switching
frequency
Voltage
drop
Maximum
voltage
rating
Maximum
current
rating
Diode medium 6.5 kV 5 kA
SCR current trigger low medium 6 kV 4 kA
TRIAC current trigger medium 1 kV 50 A
GTO current trigger low medium 6.5 kV 4.5 kA
BJT current linear medium low 1.5 kV 1 kA
MOSFET voltage linear Very high high 1 kV 200 A
IGBT voltage linear high medium 3.5 kV 2 kA

37. Properties of New Materials
Property Si GaAs 3C-SiC 6H-SiC Diamond
Bandgap at 300 K
(eV)
1.12 1.43 2.2 2.9 5.5
Relative dielectric
constant
11.8 12.8 9.7 10 5.5
Saturated drift
velocity (cm/s)

1x10
7


2x10
7

2.5x10
7

2.5x10
7

2.7x10
7

Thermal
conductivity
(W/cm/
o
C
1.5 0.5 5.0 5.0 20
Maximum
operating
temperature (K)
400 460 873 1240 1100
Melting
temperature (C)
1415 1238 Sublime>1800 Sublime>1800 Phase change
Electron mobility
at 300 K (cm
2
/Vs)
1400 8500 1000 600 2200
Breakdown
electric field
(V/cm)

3x10
5

4x10
5

4x10
6

4x10
6

1x10
7

38. Applications
•Thyristor is only used for very large power
applications.
•Forced commutated thyristors are no longer used.
•Bipolar junction transistors are no longer used.
•MOSFET is commonly used in low-power
applications.
•IGBT is used from low-power up to medium
power applications.
•GTO is used for large power applications.

39. Loss Considerations
•Conduction losses
•Switching losses
•The loss will determine the junction
temperature and the heatsink and cooler
required.
•In many cases, the switching frequency is
limited by the temperature instead of device
speed.