1. Chapter 1 Power Electronic Devices
Outline
1.1 An introductory overview of power electronic devices
1.2 Uncontrolled device—power diode
1.3 Half- controlled device—thyristor
1.4 Typical fully- controlled devices
1.5 Other new power electronic devices

2. 1.1 An introductory overview of power electronic devices
1) The concept and features
Power electronic devices: are the electronic devices that can be directly
used in the power processing circuits to convert or control electric
power.
Very often: Power electronic devices= Power semiconductor devices
Major material used in power semiconductor devices——Silicon
In broad sense
Power electronic devices
Vacuum devices: Mercury arc
rectifier thyratron, etc. . seldom
in use today
Semiconductor devices:
major power electronic devices

3. Features of power electronic devices
a) The electric power that power electronic device deals with is usually
much larger than that the information electronic device does.
b) Usually working in switching states to reduce power losses
c)Need to be controlled by information electronic circuits.
d)Very often, drive circuits are necessary to interface between
information circuits and power circuits.
e)Dissipated power loss usually larger than information electronic
devices —special packaging and heat sink are necessary.
On-state Voltage across the device is 0 p=vi=0
V=0
Off-state Current through the device is 0 p=vi=0
i=0

4. 2) Configuration of systems using power electronic devices
Power electronic system:
Protection circuit is also very often used in power electronic system
especially for the expensive power semiconductors.
Control circuit (in a broad sense)
Control
circuit
detection circuit
drive circuit
circuit
Power circuit (power
stage, main circuit)
Electric isolation:
optical, magnetic

5. Terminals of a power electronic device
Control signal from drive circuit must be connected between the control
terminal and a fixed power circuit terminal (therefore called common
terminal
A power electronic
device usually has
a third terminal —
—control terminal
to control the
states of the device
C
G
E
A power electronic device
must have at least two
terminals to allow power
circuit current flow through.
Drive
Circuit

6. Major topics for each device
Appearance, structure, and symbol
Physics of operation
Specification
Special issues
Devices of the same family
Passive components in power electronic circuit
Transformer, inductor, capacitor and resistor: these are passive
components in a power electron
ic circuit since they can not be controlled by control signal and their
characteristics are usually constant and linear.
The requirements for these passive components by power electronic
circuits could be very different from those by ordinary circuits.

7. 1.2 Uncontrolled device Power diode
 Appearance

8.  PN junction
- -
- -
-
- -
-
- - - -
- - - -
- - - -
+ + +
+
+
+
+ + +
++
+
+ + + +
+ + ++
p region
Space charge
Region
(depletion region,
potential
barrier region)
n region
Direction of
inner electric field

9. PN junction with voltage applied in the forward direction
V
+ -
p n
W
WO
-
-
-
-
-
+
+
+
+
+

10. PN junction with voltage applied in the reverse direction
V +-
p n
W
WO
-
-
-
-
-
+
+
+
+
+
Effective direction
of electronic field

11.  Construction of a practical power diode
+
V
-
Anode
Cathode
Na =10 cm
19 -3
P
+
Nd =10 cm
-3
Nd =10 cm
19 -3
-314
n+
-n
epi
substrate
10μ m
250μ m
Breakdown
Voltage dependent

12.  Features different from low-power (information electronic) diodes
–Larger size
–Vertically oriented structure
–n drift region (p-i-n diode)
–Conductivity modulation
 Junction capacitor
The positive and negative charge in the depletion region is variable with the
changing of external voltage. variable with the changing of external
voltage.
—–Junction capacitor C Junction capacitor CJ .
Junction capacitor influences the switching characteristics of
power diode.
Junction capacitor CJ
Potential barrier capacitor CB
Diffusion capacitor CD

13.  Static characteristics of power diode

Turn-off transient Turn- on transient
IF
I
O UTO UF U
IF
UF
tF t0
trr
td tf
t1 t2 t
UR
UR
P
IR
P
diF
dt
diR
dt
UFP
u
i iF
uF
tfr t0
2V

14.  Examples of commercial power diodes
part number Rated vag current VF(typical) tr(max)Rated max voltage
Fast recovery rectifiers
1N3913
SD453N25S20PC
MUR815
MUR1560
RHRU100120
Ultra-fast recovery rectifiers
Schottky rectifiers
MBR6030L
444CNQ045
30CPQ150
400V
2500V
150V
600V
1200V
30V
45V
150V
30A
400A
8A
15A
100A
60A
440A
30A
1.1V
2.2V
0.48V
1.19V
0.69V
0.975V
2.6V
1.2V
400ns
20μ s
35ns
6ns
60ns

15. 1.3 Half- controlled device—Thyristor
Another name: SCR—silicon controlled rectifier
Thyristor Opened the power electronics era
–1956, invention, Bell Laboratories
–1957, development of the 1st product, GE
–1958, 1st commercialized product, GE
–Thyristor replaced vacuum devices in almost every power processing
area.
Still in use in high power situation. Thyristor till has the
highest power-handling capability.

16.  Appearance and symbol of thyristor

17. Structure and equivalent circuit of thyristor
P1
A
G
K
N1
P2P2
N1
N2
a)
NPN
PNP
A
G
K
IG
IK
Ic2
Ic1
IA
V1
V2
b)
Structure Equivalent circuit
Equivalent
circuit

18. Physics of thyristor operation
R
NPN
PNP
A
G
S
K
EG
IG
EA
IK
Ic2
Ic1
IA
V1
V2
Equivalent circuit: A pnp transistor and an npn
transistor interconnected together
Positive feedback
Trigger
Can not be turned off by control
signal
Half-controllable

19. Quantitative description of thyristor operation
When IG =0, α1+α2 is small.
When IG >0, α1 +α2 will approach 1, IA will be very large.
I c1=
α1 IA + I CBO1 （1-1）
I c2=
α2 IK + I CBO2 （1-2）
IK=IA+IG （1-3）
IA=Ic1+Ic2 （1-4）
(
α III
)1 21
CBO2CBO1G2
A
αα +−
++
=I ( 1-5 )

20.  Other methods to trigger thyristor on
High voltage across anode and cathode—avalanche breakdown
High rising rate of anode voltagte —du/dt too high
High junction temperature
Light activation
 Static characteristics of thyristor
Blocking when reverse biased, no matter if there is gate current applied.
Conducting only when forward biased and there is triggering current
applied to the gate.
Once triggered on, will be latched on conducting even when the gate
current is no longer applied.

21.  Switching characteristics of thyristor
100%
90%
10%
u
AK
tO
0 td tr
trr tgrURRM
IRM
i
A
t

22. 1.4 Typical fully- controlled devices
 Features
–IC fabrication technology, fully- controllable, high frequency
 Applications
–Begin to be used in large amount in 1980s
–GTR is obsolete and GTO is also seldom used today.
–IGBT and power MOSFET are the two major power
semiconductor devices nowadays.

23. 1.4.1 Gate- turn- off thyristor—GTO
Major difference from conventional thyristor:
The gate and cathode structures are highly interdigitated , with various types
of geometric forms being used to layout the gates and cathodes.

24.  Physics of GTO operation
The basic operation of GTO is the
same as that of the conventional
thyristor. The principal
differences lie in the
modifications in the
structure to achieve gate turn-
off capability.
–Large α2
–α1+α2 is just a little larger than
the critical value 1.
–Short distance from gate to
cathode makes it possible to
drive current out of gate.
R
NPN
PNP
A
G
S
K
EG
IG
EA
IK
Ic2
Ic1
IA
V1
V2

25. 1.4.2 Giant Transistor—GTR
GTR is actually the bipolar junction transistor that can handle
high voltage and large current.
So GTR is also called power BJT, or just BJT.

26. Structures of GTR different from its information-processing
counterpart

27. Static characteristics of GTR
cut-off region
Amplifying (active) region
Saturation region
O
Ic
ib3
ib2
ib1
ib1<ib2<ib3
Uce

28. Second breakdown of GTR
O
ic
UCE
IB=0
IB5
IB4
IB1
IB2
IB3 Active region
Second breakdown
Quasi-saturationHard
saturation 1
-
Rd
Primary
breakdown
IB5 >IB4. etc.
IB<0
IB=0
BVCEO BVCBO
BVSUS

29. 1.4.3 Power metal- oxide- semiconductor field effect transistor—
Power MOSFET
A classification
Basic structure Symbol
Field Effect
Transistor
(FET)
Metal- onside-semiconductor FET (MOSFET) Power MOSFET
Junction FET (JFET) Static induction transistor (SIT)
n channel
p channel
N channel
G
S
D
G
S
D
P channel

30.  Physics of MOSFET operation (Off- state)
p-n- junction is
reverse-biased
off-state voltage
appears across
n- region

31.  Physics of MOSFET operation (On-state)
p-n- junction is slightly reverse biased positive gate voltage induces
conducting channel drain current flows through n- region an
conducting channel on resistance = total resistances of n-
region,conducting channel,source and drain contacts, etc.

32.  Static characteristics of power
O
iD
UDS
Ohmic
[UGS-VGS(th)=UDS]
VGS5
VGS1
VGS2
VGS3
VGS4
Active
Cut off
VGS< VGS(th)
BVDSS
VGS5> VGS4 etc.

33.  Switching characteristics of power MOSFET
Turn- on transient Turn- off transient
–Turn- on delay time td(on) –Turn- off delay time td(off)
–Rise time tr –Falling time tf
Rs
RG RF
RL
iD
uGS
up
iD
+UE
iD
O
O
O
up
t
t
t
uGS
uGSP
uT
td(on) tr td(off) tf

34. Examples of commercial power MOSFET
part number Rated vag current Qg(typical)RonRated max voltage
IRFZ48
IRF510
APT105M25BN
R IRF740
MTM15N40E
APT5025BN
APT1001RBNR
60V
100V
100V
400V
400V
500V
1000V
50A
5.6A
28A
75A
10A
15A
23A
11A
0.018Ω
0.54Ω
0.3Ω
1.0Ω
0.25Ω
0.077Ω
0.55Ω
0.025Ω
IRF540 100V
110nC
8.3 nC
171 nC
8.3 nC
63 nC
110 nC
72 nC
83nC
150 nC

35. 1.4.4 Insulated- gate bipolar transistor—IGBT
 Combination of MOSFET and GTR
GTR: low conduction losses (especially at larger blocking volta ges),
longer switching times, current- driven
MOSFET : faster switching speed, easy to drive (voltage- driven),
larger conduction losses (especially for higher blocking voltages)
IGBT

36.  Features
On- state losses are much smaller than
those of a power MOSFET, and are
comparable with those of a GTR
Easy to drive —similar to power
MOSFET
Faster than GTR, but slower than power
MOSFET
 Structure and operation principle of
IGBT
Also multiple cell structure Basic structure
similar to power MOSFET, except extra
p region On- state: minority carriers
are injected into drift region, leading to
conductivity modulation
compared with power MOSFET: slower
switching times, lower on- resistance,
useful at higher voltages (up to 1700V)
E G
C
N+
N
-
PN+
N+
P
N+
N+
P+
Emitter Gate
Collector
Injecting layer
Bufferlayer
DriftregionJ3 J2
J1

37.  Equivalent circuit and circuit symbol of IGBT
G
E
C
+
-+-
+
-
ID RN
IC
VJ1
IDRon G
C
E
Drift region
resistance

38.  Switching characteristics of IGBT
t
t
t
current tail
UGEMUGE
90%UGEM
10%UGEM
0
0
0
ICMIC
90%ICM
10%ICM
UCE UCEM
UCE（on）
ton
tfv1
toff
td(on)
tfv2
tfi1 tfi2
tftr td(off)

39.  Examples of commercial IGBT
part number Rated avg current tf(typical)VF(typical
)
Rated max voltage
Single-chip devices
HGTG32N60E2
multiple-chip power modules_
CM400HA-12E
CM300HA-24E
600V
1200V
600V
1200V
32A
30A
2.4V
3.2VHGTG30N120D2
0.62μ s
0.58μ s
400A
300A
2.7V
2.7V 0.3μ s
8.3 nC
0.3μ s

40. 1.5 Other new power electronic devices
Static induction transistor —SIT
Static induction thyristor —SITH
MOS controlled thyristor —MCT
Integrated gate- commutated thyristor —IGCT
Power integrated circuit and power module
1) Static induction transistor—SIT
Another name: power junction field effect transistor—power JFET Features
–Major- carrier device
–Fast switching, comparable to power MOSFET
–Higher power- handling capability than power MOSFET
–Higher conduction losses than power MOSFET
–Normally- on device, not convenient (could be made normally- off, but with
even higher on-state losses)

41. 2) Static induction thyristor—SITH
other names
–Field controlled thyristor—FCT
–Field controlled diode
Features
–Minority- carrier device, a JFET structure with an additional
injecting layer
–Power- handling capability similar to GTO
–Faster switching speeds than GTO
–Normally- on device, not convenient (could be made
normally- off, but with even higher on- state losses)

42. 3) MOS controlled thyristor—MCT
Essentially a GTO with integrated MOS- driven gates controlling both
turn- on and turn- off that potentially will significantly simply the
design of circuits using GTO.
The difficulty is how to design a MCT that can be turned on and turned
off equally well.
Once believed as the most promising device, but still not commercialized
in a large scale. The future remains uncertain.
4) Integrated gate- commutated thyristor — IGCT
The newest member of the power semiconductor family, introduced in
1997 by ABB
Actually the close integration of GTO and the gate drive circuit with
multiple MOSFETs in parallel providing the gate currents
Short name: GCT
Conduction drop, gate driver loss, and switching speed are superior to
GTO
Competing with IGBT and other new devices to replace GTO

43.  Review of device classifications
power electronic
devices
Current- driven (current- controlled) devices:
thyristor, GTO, GTR
Voltage- driven (voltage- controlled) devices
(Field- controlled devices):power MOSFET,IGBT,
SIT, SITH, MCT, IGCT
power electronic
devices
Pulse- triggered devices: thyristor, GTO
Level- sensitive (Level- triggered) devices:
GTR, power MOSFET, IGBT, SIT, SITH,MCT, IGCT
power electronic
devices
Uni- polar devices (Majority carrier devices):
SBD, power MOSFET, SIT
Bipolar devices (Minority carrier devices):
ordinary power diode, thyristor, , GTO, GTR,
IGCT, IGBT, SITH, MCT
Composite devices: IGBT, SITH, MCT