Power Supply Topologies
Type
of Converter
BUCK
BUCK BOOST
(Inverting)
BOOST
SEPIC
FLYBACK
FORWARD
2 SWITCH FORWARD
ACTIVE CLAMP FORWARD
HALF BRIDGE
PUSH PULL
FULL BRIDGE
PHASE SHIFT ZVT
Equations and Waveforms for
Discontinuous Mode
L
D1
D1
L
Q1
Circuit
Configuration
L1
L
D1
D1
CO
D1
Q1
CO
Q1
Q1
CO
L
NP
LP
CO
L2
D4
Q2
CO
NS
NS
NP
Q1
C1
CO
D2
NP
NS
CO
D2
D2
C2
L
D1
Q2
NP
CO
NS
Q3
D1
Q2
L
L1
Q2
Q3
CO
CO
NS
CO
CO
D1
NP
NP
NS
Q1
Q1
D3
NS
NP
Q2
Q1
D3
L
D1
L
D1
D1
C
D1
L
Q1
C1
NS
D2
Q4
D2
Q2
Q1
D2
D2
Q1
Q1
Q4
L2
Q
( )
(
)
(
( )
) ( )
Ideal Transfer
Function*
VOUT tON
=
=D
VIN
TP
Drain
Current*
IQ1 (max) = IOUT
Drain
Voltage*
VDS = VIN
VDS = VOUT
VDS = VIN - VOUT
VDS = VIN + VOUT
ID1 = IOUT x (1-D)
ID1 = IOUT
ID1 = IOUT
ID1 = IOUT
VD1 = VIN
VD1 = VOUT
VD1 = VIN - VOUT
VD1 = VOUT + VIN
Average
Diode Current*
Diode Reverse
Voltage*
Voltage
and Current
Waveforms
** Go to: power.ti.com and
place literature number in
the “Key Word” box.
For SEM topics, go to:
power.ti.com/seminars
IQ1 (max) = IOUT x
( )
1
1-D
VOUT
tON
D
==TP - tON
1-D
VIN
IQ1 (max) = IOUT x
VOUT
D
=
1-D
VIN
( )
1
1-D
IQ1 (max) = IOUT x
TP x VOUT
2 x IOUT x LP
VOUT
= Dx
VIN
( )
D
1-D
IQ1 (max) =
(
VIN x tON
LP
VDS = VIN + VOUT x
( )( ) ( )
t
VOUT NS
x ON
=
NP
TP
VIN
)
IQ1 (max) =
( )
NP
NS
ID1 = IOUT
VD1 = VOUT+ VIN x
( )
NS
NP
=
NS
xD
NP
( )
NS
x IOUT
NP
( )( )( )
t
VOUT NS
N
x ON = S x D
=
NP
TP
NP
VIN
IQ1 (max) =
( )
NS
x IOUT
NP
VDS = 2 x VIN
VDS = VIN
ID1 = IOUT x D
ID1 = IOUT x D
VD1 = VOUT + VIN x
( )
NS
NP
( )( )( )
t
VOUT NS
N
x ON = S x D
=
NP
TP
NP
VIN
VD1 = VOUT + VIN x
IQ1 (max) =
( )
NS
x IOUT
NP
VDS = VIN x
1
1-D
NS
NP
VD1 = VOUT + VIN x
( )( ) ( )
VOUT
N
t
N
= 2 x S x ON = 2 x S x D
NP T P
NP
VIN
( )
NS
x IOUT
NP
IQ1 (max) =
( )
ID1 = IOUT x D
( )
( )( )( )
VOUT NS tON
N
=
x
= S xD
NP
TP
NP
VIN
VDS = VIN
(
)
ID1 = IOUT x D +
( )( )
NS
1
x
NP
1-D
(
( )
NS
NP
PWM
)
ID1 = IOUT x D +
VD1 = VIN x
IOUT
x (1-2 D)
2
( )( ) ( )
VOUT
N
t
N
= 2 x S x ON = 2 x S x D
NP TP
NP
VIN
( )
NS
x IOUT
NP
IQ1 (max) =
VDS = 2 x VIN
IOUT
x (1-2 D)
2
VD1 = VIN x
( )
NS
x IOUT
NP
IQ1 (max) =
( )( ) ( )
VOUT
N
t
N
= 2 x S x ON = 2 x S x D
NP TP
NP
VIN
IQ1 (max) =
VDS = VIN
(
)
ID1 = IOUT x D +
( )
NS
x2
NP
VD1 = VIN x
IOUT
x (1-2 D)
2
ID1 =
( )
NS
x2
NP
PWM
PWM
VIN
VDS(Q1)
VIN
VDS(Q1)
VIN
VIN
VDS(Q1)
VIN
VIN
VIN
VIN
VIN
VIN
VIN
VIN
VDS(Q1)
VDS(Q1)
VDS(Q1)
VDS(Q1)
VDS(Q1)
VDS(Q1)
VDS(Q1)
VDS(Q1)
VDS(Q1)
IQ1
IQ1
IQ1
IQ1
IQ1
IQ1
IQ1
IQ1
IQ1
IQ2
IQ1
IQ2
IQ1
IQ2
IQ1
ID1
ID1
ID1
ID1
ID1
ID1
ID1
ID1
ID1
ID2
ID1
ID2
ID1
ID2
ID1
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
IL
V
V
V
V
VS
VS
VS
VS
VS
VS
VS
VS
TP
Application Notes:**
Understanding Buck Power
Stages in Switchmode Power Supplies
(SLVA057)
Under the Hood of Low Voltage
DC/DCConverters
(SLUP206)
Controllers/Converters:
TPS40020/21
TPS40007/09
TPS40040/41
TPS40075
TPS40077
TPS40140
TPS40180
TPS40192/3
TPS40200
TPS5410/20/30/50
TPS54350/550
TPS62110
The platform bar is a trademark of Texas Instruments.
© 2010 Texas Instruments Incorporated. Printed in the U.S.A.
Printed on recycled paper.
tON
TP
Application Notes:**
Understanding Boost Power Stages
in Switchmode Power Supplies (SLVA061)
High Voltage Power Supply Using a
Highly Integrated DC/DC Converter
(SLVA137)
Under the hood of a Boost Converter
(SEM1800 Topic 3)
Controllers/Converters:
TPS40210/11
UCC38050/51 (PFC)
TPS61080
UCC3817A/18A (PFC)
TPS61030
UCC3809-1
TPS61100
TPS61200
UCC28019A
UCC28060 (PFC)
UCC28061
UCC28070
UCC28220/21
UCC38C42
UCC3800
tON
TP
Application Notes:**
Understanding Buck-Boost Power
Stages in Switchmode Power Supplies
(SLVA059A)
Controllers/Converters:
TPS40200
TPS40061
TPS40057
TPS5410/20/30/50
TPS54350/54550
TPS63700
UC3572
UCC3801/01/02/03/04/05
UCC3807
UCC3810 (Dual)
UCC3813
UCC38C40/41/42/43/45
tON
TP
Application Notes:**
Versatile Low Power SEPIC Converter
Accepts Wide Input Voltage Range
(SLUA158)
High Power Factor Preregulator
Using the SEPIC Converter
(SLUP103)
Controllers/Converters:
TPS43000
TPS61130
UCC38C40/41/42/43/44/45
UCC3800/01/02/03/04/05/3813
UCC3807
UCC3810 (Dual)
tON
TP
Application Notes:**
Design of Flyback Transformers
and Inductors
(SLUP076)
Switching Power Supply Design
Review – 60 Watt Flyback Regulator
(SLUP072)
Controllers:
TPS23750/70 (PoE)
UCC3807
UCC28220/21
UCC28600 (Green Mode)
UCC28610
UCC35701/702
UCC35705/706
UCC3800/01/02/03/04/05/3813
UCC3809
UCC3810 (Dual)
UCC38C40/41/42/43/44/45
PWM
tON
tON
TP
Application Notes:**
25-W Forward Converter
Design Review
Controllers:
UCC28220/21
UCC35701/702
UCC35705/706
UCC3800/01/02/03/04/05/3813
UCC3807
UCC3809
UCC3810 (Dual)
UCC38C40/41/42/43/44/45
(SLUA276)
TP
Application Notes:**
Practical Considerations in Current
Mode Power Supplies
(SLUA110)
Controllers:
UCC27200/01 (MOSFET Driver)
UCC28220/21
UCC35701/702
UCC35705/706
UCC3801/04/05/13
UCC3807
UCC3809
UCC3810 (Dual)
UCC38C41/44/45
tON
PWM
tON
TP
Application Notes:**
Active Clamp and Reset Technique
Enhances Forward Converter
Performance
(SLUP108)
Design Considerations for Active
Clamp and Reset Technique (SLUP112)
Understanding and Designing an
Active Clamp Current Mode
Controlled Converter
(SLUA535)
Controllers:
UCC2891, 2 ,3 ,4, 7
UCC2897A
UCC3580-1
UC3824
TP
Application Notes:**
Practical Considerations in
Current Mode Power Supplies (SLUA110)
Zero Voltage Switching
Resonant Power Conversion (SLUA159)
Controllers:
UC28025
UC3825A, B
UCC25600
UCC27200/01 (MOSFET Driver)
UCC28089 (2 x 50%)
UCC28250
UCC3806
UCC3808A
UCC38083/84/85/86
PWM
tON
TP
Application Notes:**
1.5 MHz Current Mode IC Controlled
50-Watt Power Supply
(SLUA053)
The UC3823A,B and UC3825A,B
Enhanced Generation of PWM
Controllers
(SLUA125)
Controllers:
UC28025
UC3825A, B
UCC28089 (2 x 50%)
UCC28250
UCC3806
UCC3808A
UCC38083/84/85/86
1
x IOUT
2
( )
NS
NP
PWM
PWM
PWM
NS
x IOUT
NP
VD1 = VIN x
PWM
PWM
( )
VDS = VIN
PWM
tON
* Excludes ripple current and
output diode voltage drop.
Continuous conduction
mode shown (unless
otherwise noted). For
reliable operation follow
recommendations in
datasheets and application
notes.
VOUT
TP
1
=
=
TP-tON (1-D)
VIN
tON
IQ2
ID2
IL2
tON
TP
TP
Application Notes:**
The UC3823A,B and UC3825A,B
Enhanced Generation of PWM
Controllers
(SLUA125)
Practical Considerations in
Current Mode Power Supplies (SLUA110)
Controllers:
UC28025
UCC27200/01 (MOSFET Driver)
UCC28089 (2 x 50%)
UCC28230/1
UCC3806
UCC3808A
UCC38083/84/85/86
UC3825A, B
Application Notes:**
Design Review: 500-W, 40-W/in3 Phase
Shifted ZVT Power Converter (SLUP102)
Phase Shifted, Zero Voltage Transition
Design Considerations
(SLUA107)
Controllers:
UCC28950
UC3875
UC3879
UCC3895
SLUW001E
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