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Electronics 1 Part6
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Electronics- lectures for Mechanical Engineering
part 6
Dr. Bogusław Boratyński
Faculty of Microsystems Electronics and Photonics,
Wroclaw University of Technology,
2011
From the course syllabus
Basic literature & figure sources:
G. Rizzoni, Fundamentals of Electrical Engineering, McGraw-Hill
R.F. Pierret, Semiconductor Device Fundamentals, Addison-Wesley Publ.,
B.G. Streetman, Solid State Electronic Devices, Prentice-Hall,
J. Millman, Microelectronics, McGraw-Hill
Additional literature:
W. Marciniak, Przyrządy półprzewodnikowe i układy scalone, WNT,
A. Świt, J. Pułtorak, Przyrządy półprzewodnikowe, WNT,
B.G. Streetman, Przyrządy półprzewodnikowe, WNT
Digital integrated circuits
Chapter 6. Thyristors.
DC and AC power switching
AC switching devices:
Thyristor, TRIAC, DIAC
DC switches:
IGBT,
PUT, UJT
MOSFET or bipolar transistor current switch
Input control signal UI = UBE or I1=IB
Result: rise of output current IC =Iload
U0
UI
UCCload
IC
IB
Input control signal UG = UGS
Result: rise of output current iD = iload
UDD , UCC - DC supply
Thyristor – switch - dc operation
Source: J. Millman, Microelectronics, McGraw-Hill
DC biasing circuit: UGK >0, UAK >0 DC I-V characteristics
pulse of IG to switch-on (to trigger)
RL
A
K
G
UGK
IGUAK
blocking
conducting
reverse
Thyristor
SCR – Silicon Controlled Rectifier
Thyristor – operation principle
Source: J. Millman, Microelectronics, McGraw-Hill
p-n-p-n structure,
3 p-n junctions in series
Thyristor
SCR – Silicon Controlled Rectifier
”Diode” current controlled
by the gate current pulse
blocking
conducting
reverse
switching
Triggering methods:
1. Pulse of the gate current IG
2. Rise of VAK > VBF
3. Illumination – Light triggered thyristors
Main current – IAK = Iload [A] [kA]
Control current pulse – IG [mA]
Thyristor – circuit application - ac current switch
G
A K
pow er line
230V
LOAD
lighting
system
gate contol
circuit
Basic application system example:
control of light intensity / light dimmer
(heating systems, electrical motors)
Uinput
IAK
UAK
ωt
ωt
ωt
IG pulse
current & voltage waveforms
DIAC
DIODE
SCR
Iload
Thyristor – circuit application - ac current switch
G
A K
pow er line
230V
LOAD
lighting
system
gate contol
circuit
Basic application system example:
control of light intensity / light dimmer
(heating systems, electrical motors)
current & voltage waveforms
G
A K
pow er line
230V
LOAD
lighting
system
gate contol
circuit
Uinput
IAK
UAK
ωt
ωt
ωt
IG pulse
Iload
TRIAC – operation principle
TRIAC – bidirectional thyristor - symmetrical I-V characteristic
(equivalent of two thyristors connected antiparallel) IG pulse turns-on the triac
A1
A2
G
IG pulse
IG pulse
conducting
conducting
blocking
blocking
Application in low and medium power circuits
TRIAC – operation principle - ac current switch
TRIAC – ac operation
A1
A2
G
IG pulse
Uinput
IAK
UAK
ωt
ωt
ωt
IG pulse
Iload
DIAC – operation principle
Source J. Millman, Microelectronics, McGraw-Hill
DIAC – two terminal switching device - symmetrical I-V characteristic
switching – voltage rise Vth= 40V ÷ 60V
A2VthVth
IGBT switching device
- low UCE in on-state
- very high switching voltages [kV]
IGBT Insulated Gate Bipolar Transistor
- takes advantage of MOSFET current-less input and BJT high switching current capability
Source:
- symbol
- equivalent circuit
IGBT switching device
IGBT Insulated Gate Bipolar Transistor
- application circuit
Source: Wikipedia
=
uC – microcontroller, triggering cct.
PUT unijunction transistor
PUT Programmable Unijunction Transistor
Switching voltage Vp adjustable by external resistance voltage divider and supply VBB
A
K
G
UJT - Unijunction Transistor