FAIRCHILD FSFR1700

FSFR-Series — Fairchild Power Switch (FPS™)
for Half-Bridge Resonant Converters
Features
Description
ƒ
The FSFR-series are a highly integrated power switches
designed for high-efficiency half-bridge resonant
converters. Offering everything necessary to build a
reliable and robust resonant converter, the FSFR-series
simplifies designs and improves productivity, while
improving performance. The FSFR-series combines
power MOSFETs with fast-recovery type body diodes, a
high-side gate-drive circuit, an accurate current
controlled oscillator, frequency limit circuit, soft-start, and
built-in protection functions. The high-side gate-drive
circuit has a common-mode noise cancellation
capability, which guarantees stable operation with
excellent noise immunity. The fast-recovery body diode
of the MOSFETs improves reliability against abnormal
operation conditions, while minimizing the effect of the
reverse recovery. Using the zero-voltage-switching (ZVS)
technique dramatically reduces the switching losses and
efficiency is significantly improved. The ZVS also
reduces the switching noise noticeably, which allows a
small-sized Electromagnetic Interference (EMI) filter.
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ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Variable Frequency Control with 50% Duty Cycle
for Half-bridge Resonant Converter Topology
High Efficiency through Zero Voltage Switching (ZVS)
Internal SuperFET™s with Fast-Recovery Type
Body Diode (trr=120ns) for FSFR2100 and UniFETs
with Fast-Recovery Type Body Diode (trr<160ns) for
FSFR2000/1900/1800/1700.
Fixed Dead Time (350ns) Optimized for MOSFETs
Up to 300kHz Operating Frequency
Pulse Skipping for Frequency Limit (Programmable)
at Light-Load Condition
Remote On/Off Control Using Control Pin
Protection Functions: Over-Voltage Protection
(OVP), Over-Load Protection (OLP), Over-Current
Protection (OCP), Abnormal Over-Current Protection
(AOCP), Internal Thermal Shutdown (TSD)
The FSFR-series can be applied to various resonant
converter topologies such as series resonant, parallel
resonant, and LLC resonant converters.
Applications
ƒ
ƒ
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PDP and LCD TVs
Desktop PCs and servers
Adapters
Telecom Power Supplies
Audio Power Supplies
Related Resources
AN4151 — Half-bridge LLC Resonant Converter Design
TM
using FSFR-series Fairchild Power Switch (FPS )
Ordering Information
Part
Number
Package
Operating
Junction
Temperature
RDS(ON_MAX)
Maximum Output Power Maximum Output
without Heatsink
Power with Heatsink
(1,2)
(1,2)
(VIN=350~400V)
(VIN=350~400V)
FSFR2100
0.38Ω
200W
450W
FSFR2000
0.67Ω
160W
350W
0.85Ω
140W
300W
FSFR1800
0.95Ω
120W
260W
FSFR1700
1.25Ω
100W
200W
FSFR1900
9-SIP
-40 to +130°C
Notes:
1. The junction temperature can limit the maximum output power.
2. Maximum practical continuous power in an open-frame design at 50°C ambient.
All standard Fairchild Semiconductor products are RoHS compliant and many are also “GREEN” or going green. For Fairchild’s
definition of “green” please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
May 2008
D1
Cr
Llk
LVcc
VCC
Np
HVCC
Lm
Ns
RT
CON
CDL
VIN
Vo
Ns
VDL
Control
IC
D2
VCTR
KA431
CS
SG
PG
Rsense
Figure 1. Typical Application Circuit (LLC Resonant Half-bridge Converter)
Block Diagram
CF RF
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Application Circuit Diagram
1.5 μ s
Figure 2. Internal Block Diagram
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
2
1
VDL
2
3 4 5 6 7 8
RT SG LVcc
CON CS PG
9
10
VCTR
HVcc
Figure 3. Package Diagram
Pin Definitions
Pin #
Name
Description
1
VDL
This is the drain of the high-side MOSFET, typically connected to the input DC link voltage.
2
CON
This pin is for enable/disable and protection. When the voltage of this pin is above 0.6V, the
IC operation is enabled. When the voltage of this pin drops below 0.4V, gate drive signals
for both MOSFETs are disabled. When the voltage of this pin increases above 5V,
protection is triggered.
3
RT
This pin programs the switching frequency. Typically, an opto-coupler is connected to
control the switching frequency for the output voltage regulation.
4
CS
This pin senses the current flowing through the low-side MOSFET. Typically, negative
voltage is applied on this pin.
5
SG
This pin is the control ground.
6
PG
This pin is the power ground. This pin is connected to the source of the low-side MOSFET.
7
LVCC
This pin is the supply voltage of the control IC.
8
NC
9
HVCC
This is the supply voltage of the high-side gate-drive circuit IC.
10
VCTR
This is the drain of the low-side MOSFET. Typically, a transformer is connected to this pin.
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Pin Configuration
No connection.
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
3
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In
addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only. TA=25°C unless otherwise specified.
Symbol
VDS
LVCC
Parameter
Min.
Maximum Drain-to-Source Voltage
(VDL-VCTR and VCTR-PG)
FSFR2100
600
All Others
500
Low-side Supply Voltage
Max.
Unit
V
-0.3
25.0
V
-0.3
25.0
V
FSFR2100
-0.3
625.0
All Others
-0.3
525.0
HVCC to VCTR High-side VCC Pin to Low-side Drain Voltage
HVCC
High-side Floating Supply Voltage
VCON
Control Pin Input Voltage
-0.3
LVCC
V
VCS
Current Sense (CS) Pin Input Voltage
-5.0
1.0
V
VRT
RT Pin Input Voltage
-0.3
5.0
V
50
V/ns
dVCTR/dt
PD
Allowable Low-side MOSFET Drain Voltage Slew Rate
Total Power Dissipation
(3)
FSFR2100
12.0
FSFR2000
12.0
FSFR1900
11.8
FSFR1800
11.7
FSFR1700
TJ
TSTG
Maximum Junction Temperature
+150
(4)
Storage Temperature Range
W
11.6
(4)
Recommended Operating Junction Temperature
V
-40
+130
-55
+150
°C
°C
MOSFET Section
VDGR
Drain Gate Voltage (RGS=1MΩ)
VGS
Gate Source (GND) Voltage
IDM
Drain Current Pulsed
FSFR2000
Continuous Drain Current
FSFR1900
FSFR1800
FSFR1700
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
600
All Others
500
V
±30
FSFR2100
ID
FSFR2100
FSFR2100
33
FSFR2000
31
FSFR1900
26
FSFR1800
23
FSFR1700
20
TC=25°C
11
TC=100°C
7
TC=25°C
9.5
TC=100°C
6
TC=25°C
8
TC=100°C
5
TC=25°C
7
TC=100°C
4.5
TC=25°C
6
TC=100°C
3.9
V
A
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Absolute Maximum Ratings
A
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4
Symbol
Parameter
Min.
Max.
Unit
Package Section
Torque
Recommended Screw Torque
5~7
kgf·cm
Notes:
3. Per MOSFET when both MOSFETs are conducting.
4. The maximum value of the recommended operating junction temperature is limited by thermal shutdown.
Thermal Impedance
TA=25°C unless otherwise specified.
Symbol
θJC
Parameter
Junction-to-Case Center Thermal Impedance
(Both MOSFETs Conducting)
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
Value
FSFR2100
10.44
FSFR2000
10.44
FSFR1900
10.56
FSFR1800
10.68
FSFR1700
10.79
Unit
ºC/W
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Absolute Maximum Ratings (Continued)
www.fairchildsemi.com
5
TA=25°C unless otherwise specified.
Symbol
Parameter
Test Conditions
Specifications
Min.
Typ.
Unit
Max.
MOSFET Section
FSFR2100
BVDSS
Drain-to-Source
Breakdown Voltage
All Others
RDS(ON)
trr
On-State Resistance
Body Diode Reverse
(5)
Recovery Time
ID=200μA, TA=25°C
600
650
ID=200μA, TA=125°C
ID=200μA, TA=25°C
V
500
ID=200μA, TA=125°C
540
FSFR2100
VGS=10V, ID=5.5A
0.32
0.38
FSFR2000
VGS=10V, ID=5.0A
0.53
0.67
FSFR1900
VGS=10V, ID=4.0A
0.74
0.85
FSFR1800
VGS=10V, ID=3.0A
0.77
0.95
FSFR1700
VGS=10V, ID=2.0A
1.00
1.25
FSFR2100
VGS=0V, IDiode=11.0A,
dIDiode/dt=100A/μs
120
FSFR2000
VGS=0V, IDiode=9.5A,
dIDiode/dt=100A/μs
125
FSFR1900
VGS=0V, IDiode=8.0A,
dIDiode/dt=100A/μs
140
FSFR1800
VGS=0V, IDiode=7.0A,
dIDiode/dt=100A/μs
160
FSFR1700
VGS=0V, IDiode=6.0A,
dIDiode/dt=100A/μs
160
Ω
ns
Supply Section
ILK
Offset Supply Leakage Current
H-VCC=VCTR=600V/500V
50
μA
IQHVCC
Quiescent HVCC Supply Current
(HVCCUV+) - 0.1V
50
120
μA
IQLVCC
Quiescent LVCC Supply Current
(LVCCUV+) - 0.1V
100
200
μA
IOHVCC
Operating HVCC Supply Current
(RMS Value)
fOSC=100KHz, VCON > 0.6V
6
9
mA
No switching, VCON < 0.4V
100
200
μA
IOLVCC
Operating LVCC Supply Current
(RMS Value)
fOSC=100KHz, VCON > 0.6V
7
11
mA
No switching, VCON < 0.4V
2
4
mA
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Electrical Characteristics
UVLO Section
LVCCUV+
LVCC Supply Under-Voltage Positive Going Threshold (LVCC Start)
13.0
14.5
16.0
V
LVCCUV-
LVCC Supply Under-Voltage Negative Going Threshold (LVCC Stop)
10.2
11.3
12.4
V
LVCCUVH
LVCC Supply Under-Voltage Hysteresis
HVCCUV+
HVCC Supply Under-Voltage Positive Going Threshold (HVCC Start)
8.2
9.2
10.2
V
HVCCUV-
HVCC Supply Under-Voltage Negative Going Threshold (HVCC Stop)
7.8
8.7
9.6
V
HVCCUVH
HVCC Supply Under-Voltage Hysteresis
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
3.2
0.5
V
V
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6
TA=25°C unless otherwise specified.
Specifications
Symbol
Parameter
Unit
Test Conditions
Min
Typ
Max
Oscillator & Feedback Section
VCONDIS
Control Pin Disable Threshold Voltage
0.36
0.40
0.44
V
VCONEN
Control Pin Enable Threshold Voltage
0.54
0.60
0.66
V
VRT
V-I Converter Threshold Voltage
1.5
2.0
2.5
V
fOSC
Output Oscillation Frequency
94
100
106
KHz
DC
Output Duty Cycle
48
50
52
%
fSS
Internal Soft-Start Initial Frequency
tSS
Internal Soft-Start Time
RT=5.2KΩ
fSS=fOSC+40kHz,
RT=5.2KΩ
140
KHz
2
3
4
ms
Protection Section
IOLP
OLP Delay Current
VCON=4V
3.6
4.8
6.0
μA
VOLP
OLP Protection Voltage
VCON > 3.5V
4.5
5.0
5.5
V
VOVP
LVCC Over-Voltage Protection
L-Vcc > 21V
21
23
25
V
VAOCP
AOCP Threshold Voltage
ΔV/Δt=-0.1V/µs
-1.0
-0.9
-0.8
V
VCS < VAOCP;
ΔV/Δt=-0.1V/µs
(5)
tBAO
AOCP Blanking Time
VOCP
OCP Threshold Voltage
V/Δt=-1V/µs
VCS < VOCP;
ΔV/Δt=-1V/µs
(5)
tBO
OCP Blanking Time
tDA
Delay Time (Low Side) Detecting from VAOCP
(5)
to Switch Off
TSD
Thermal Shutdown Temperature
ISU
Protection Latch Sustain LVCC Supply
Current
VPRSET
50
-0.64
-0.58
-0.52
V
1.0
1.5
2.0
μs
250
400
ns
130
150
°C
100
150
μA
ΔV/Δt=-1V/µs
(5)
110
LVcc=7.5V
Protection Latch Reset LVCC Supply Voltage
ns
5
V
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Electrical Characteristics (Continued)
Dead-Time Control Section
DT
Dead Time
(6)
350
ns
Notes:
5. This parameter, although guaranteed, is not tested in production.
6. These parameters, although guaranteed, are tested only in EDS (wafer test) process.
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
7
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
These characteristic graphs are normalized at TA=25ºC.
1
0.95
1
0.95
0.9
0.9
-50
-25
0
25
50
75
-50
100
-25
0
O
Temp ( C)
Temp
50
75
100
(OC)
Figure 5. Switching Frequency vs. Temp.
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
Figure 4. Low-side MOSFET Duty Cycle vs. Temp.
1
0.95
0.9
1
0.95
0.9
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temp (OC)
Temp (OC)
Figure 6. High-side VCC (HVCC) Start vs. Temp.
Figure 7. High-side VCC (HVCC) Stop vs. Temp.
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
25
1
0.95
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Typical Performance Characteristics
1
0.95
0.9
0.9
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temp (OC)
Temp (OC)
Figure 8. Low-side VCC (LVCC) Start vs. Temp.
Figure 9. Low-side VCC (LVCC) Stop vs. Temp.
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
8
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
These characteristic graphs are normalized at TA=25ºC.
1
0.95
0.95
0.9
0.9
-50
-25
0
25
50
75
-50
100
-25
0
50
75
100
Temp (OC)
Figure 10. OLP Delay Current vs. Temp.
Figure 11. OLP Protection Voltage vs. Temp.
1.1
1.1
1.05
1.05
1
0.95
1
0.95
0.9
0.9
-50
-25
0
25
50
75
-50
100
-25
0
Temp (OC)
25
Temp
Figure 12. LVCC OVP Voltage vs. Temp.
50
75
100
(OC)
Figure 13. RT Voltage vs. Temp.
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
25
Temp (OC)
Normalized at 25OC
Normalized at 25OC
1
1
0.95
0.9
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Typical Performance Characteristics (Continued)
1
0.95
0.9
-50
-25
0
25
50
75
-50
100
-25
0
25
50
75
100
Temp (OC)
Temp (OC)
Figure 14. CON Pin Enable Voltage vs. Temp.
Figure 15. OCP Voltage vs. Temp.
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
9
1. Basic Operation: FSFR-series is designed to drive
high-side and low-side MOSFETs complementarily with
50% duty cycle. A fixed dead time of 350ns is introduced
between consecutive transitions, as shown in Figure 16.
Gain
1.8
f min
f max
f normal
f ISS
1.6
Dead time
High side
MOSFET
gate drive
1.4
1.2
Low side
MOSFET
gate drve
1.0
Soft-start
0.8
time
Figure 16. MOSFETs Gate Drive Signal
0.6
60
70
80
90
100
110
120
140
130
150
freq (kHz)
2. Internal Oscillator: FSFR-series employs a currentcontrolled oscillator, as shown in Figure 17. Internally,
the voltage of RT pin is regulated at 2V and the
charging/discharging current for the oscillator capacitor,
CT, is obtained by copying the current flowing out of RT
pin (ICTC) using a current mirror. Therefore, the switching
frequency increases as ICTC increases.
Figure 18. Resonant Converter Typical Gain Curve
LVcc
VDL
RT
Rmax
Rmin
Rss
Css CON
Control
IC
SG
PG
Figure 19. Frequency Control Circuit
The minimum switching frequency is determined as:
Figure 17. Current Controlled Oscillator
f min =
3. Frequency Setting: Figure 18 shows the typical
voltage gain curve of a resonant converter, where the
gain is inversely proportional to the switching frequency
in the ZVS region. The output voltage can be regulated
by modulating the switching frequency. Figure 19 shows
the typical circuit configuration for RT pin, where the
opto-coupler transistor is connected to the RT pin to
modulate the switching frequency.
5.2k Ω
× 100(kHz )
Rmin
(1)
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Functional Description
Assuming the saturation voltage of opto-coupler
transistor is 0.2V, the maximum switching frequency is
determined as:
f max = (
5.2k Ω 4.68k Ω
+
) × 100(kHz )
Rmin
Rmax
(2)
To prevent excessive inrush current and overshoot of
output voltage during start-up, increase the voltage gain
of the resonant converter progressively. Since the
voltage gain of the resonant converter is inversely
proportional to the switching frequency, the soft-start is
implemented by sweeping down the switching frequency
ISS
from an initial high frequency (f ) until the output
voltage is established. The soft-start circuit is made by
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
10
f ISS = (
5.2k Ω 5.2k Ω
) × 100 + 40 (kHz ) (3)
+
Rmin
RSS
It is typical to set the initial frequency of soft-start two ~
three times the resonant frequency (fO) of the resonant
network.
The soft-start time is three to four times of the RC time
constant. The RC time constant is as follows:
TSS = RSS ⋅ CSS
Figure 22. Control Pin Configuration for Pulse
Skipping
(4)
Remote On / Off: When an auxiliary power supply is
used for standby, the main power stage using FSFRseries can be shut down by pulling down the control pin
voltage, as shown in Figure 23. R1 and C1 are used to
ensure soft-start when switching resumes.
fs
f ISS
40kHz
Control loop
take over
time
Figure 20. Frequency Sweeping of Soft-start
4. Control Pin: The FSFR-series has a control pin for
protection, cycle skipping, and remote on/off. Figure 21
shows the internal block diagram for control pin.
Figure 23. Remote On / Off Circuit
5. Protection Circuits: The FSFR-series has several
self-protective functions, such as Overload Protection
(OLP), Over-Current Protection (OCP), Abnormal OverCurrent Protection (AOCP), Over-Voltage Protection
(OVP), and Thermal Shutdown (TSD). OLP, OCP, and
OVP are auto-restart mode protections; while AOCP and
TSD are latch-mode protections, as shown in Figure 24.
Figure 21. Internal Block of Control Pin
Protection: When the control pin voltage exceeds 5V,
protection is triggered. Detailed applications are
described in the protection section.
Pulse Skipping: FSFR-series stops switching when the
control pin voltage drops below 0.4V and resumes
switching when the control pin voltage rises above 0.6V.
To use pulse-skipping, the control pin should be
connected to the opto-coupler collector pin. The
frequency that causes pulse skipping is given as:
SKIP
=
5.2 k
4.16 k
+
R min
R max
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
x100 (kHz)
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
connecting R-C series network on the RT pin, as shown
in Figure 19. FSFR-series also has an internal soft-start
for 3ms to reduce the current overshoot during the initial
cycles, which adds 40kHz to the initial frequency of the
external soft-start circuit, as shown in Figure 20. The
initial frequency of the soft-start is given as:
Auto-restart Mode Protection: Once a fault condition is
detected, switching is terminated and the MOSFETs
remain off. When LVCC falls to the LVCC stop voltage of
11.3V, the protection is reset. The FPS resumes normal
operation when LVCC reaches the start voltage of 14.5V.
(5)
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11
Current Sensing Using Resonant Capacitor Voltage:
For high-power applications, current sensing using a
resistor may not be available due to the severe power
dissipation in the resistor. In that case, indirect current
sensing using the resonant capacitor voltage can be a
good alternative because the amplitude of the resonant
p-p
capacitor voltage (Vcr ) is proportional to the resonant
p-p
current in the primary side (Ip ) as:
VCr p − p =
I p p− p
(6)
2π f sCr
To minimize power dissipation, a capacitive voltage
divider is generally used for capacitor voltage sensing,
as shown in Figure 27.
Figure 24. Protection Blocks
Np
CON
Current Sensing Using Resistor: FSFR-series senses
drain current as a negative voltage, as shown in Figure
25 and Figure 26. Half-wave sensing allows low power
dissipation in the sensing resistor, while full-wave
sensing has less switching noise in the sensing signal.
Cd
Control
IC
Ns
Ip
Rd
SG
Cr
PG
Ns
100
VSENSE
Np
CB
Ns
Cr
CSENSE
Ip
Ns
Control
IC
VCS
Ids
CS
SG
VCr
PG
VCrp-p
Rsense
VCS
Ids
Vsense
Vsense pk
CB
=
VCr p − p Csense + CB
Vsense pk
= VCON
2
Vsensepk
Figure 25. Half-wave Sensing
VCON
Ids
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Latch-Mode Protection: Once this protection is
triggered, switching is terminated and the MOSFETs
remain off. The latch is reset only when LVCC is
discharged below 5V.
Vsensepk
Tdelay = Rd Cd
VCS
Figure 27. Current Sensing Using Resonant
Capacitor Voltage
5.1 Over-Current Protection (OCP): When the sensing
pin voltage drops below -0.6V, OCP is triggered and the
MOSFETs remain off. This protection has a shutdown
time delay of 1.5µs to prevent premature shutdown
during startup.
Cr
Control
IC
VCS
Np
CS
PG
SG
Rsense
Ns
5.2 Abnormal Over-Current Protection (AOCP): If the
secondary rectifier diodes are shorted, large current with
extremely high di/dt can flow through the MOSFET
before OCP or OLP is triggered. AOCP is triggered
without shutdown delay when the sensing pin voltage
Ns
Ids
Figure 26. Full-wave Sensing
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
12
6. PCB Layout Guideline: Duty unbalance problems
may occur due to the radiated noise from main
transformer, the inequality of the secondary side leakage
inductances of main transformer, and so on. Among
them, it is one of the dominant reasons that the control
components in the vicinity of RT pin are enclosed by the
primary current flow pattern on PCB layout. The direction
of the magnetic field on the components caused by the
primary current flow is changed when the high and low
side MOSFET turns on by turns. The magnetic fields with
opposite direction from each other induce a current
through, into, or out of the RT pin, which makes the turnon duration of each MOSFET different. It is highly
recommended to separate the control components in the
vicinity of RT pin from the primary current flow pattern on
PCB layout. Figure 28 shows an example for the duty
balanced case.
5.3 Overload Protection (OLP): Overload is defined as
the load current exceeding its normal level due to an
unexpected abnormal event. In this situation, the
protection circuit should trigger to protect the power
supply. However, even when the power supply is in the
normal condition, the overload situation can occur during
the load transition. To avoid premature triggering of
protection, the overload protection circuit should be
designed to trigger only after a specified time to
determine whether it is a transient situation or a true
overload situation. Figure 27 shows a typical overload
protection circuit. By sensing the resonant capacitor
voltage on the control pin, the overload protection can be
implemented. Using RC time constant, shutdown delay
can be also introduced. The voltage obtained on the
control pin is given as:
VCON =
where VCr
voltage.
p-p
CB
VCr p − p
2(CB + Csense )
(7)
is the amplitude of the resonant capacitor
5.4 Over-Voltage Protection (OVP): When the LVCC
reaches 23V, OVP is triggered. This protection is used
when auxiliary winding of the transformer to supply VCC
to FPS is utilized.
5.5 Thermal Shutdown (TSD): The MOSFETs and the
control IC in one package makes it easy for the control
IC to detect the abnormal over-temperature of the
MOSFETs. If the temperature exceeds approximately
130°C, the thermal shutdown triggers.
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
Figure 28. Example for Duty Balancing
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
drops below -0.9V. This protection is latch mode and
reset when LVCC is pulled down below 5V.
www.fairchildsemi.com
13
Application
FPS™ Device
Input Voltage Range
Rated Output Power
Output Voltage
(Rated Current)
LCD TV
FSFR2100
400V
(20ms hold-up time)
192W
24V-8A
Features
ƒ
ƒ
ƒ
High efficiency ( >94% at 400VDC input)
Reduced EMI noise through zero-voltage-switching (ZVS)
Enhanced system reliability with various protection functions
C102
22nF/
630V
Brownout circuit
D211
FYP2010DN
EER3542
VCC=16~20VDC
1
C109
22µF
U5
R114
10k
R109
1M
R112
10k
U4
ZD101
6.8V
R110
1M
C111
330n/
275VAC
LVCC
HVCC
Line
Filter
R108
open
R107
2.2k
U2
C108
12nF
Vin=340~390Vdc
Control
IC
8
9
VCTR
D212
FYP2010DN
CS
U3
KA431
JP1, 0
R102
1kΩ
SG
PG
C204
12nF
R204
62k
R206
2k
U2
C203
47nF
R203
33k
C301
R205
7k
C103
100pF
R101
0.2Ω
Figure 29. Typical Application Circuit
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
R201
10k
R202
1k
C104
open
R103, 0
C110 330n/
275VAC
NTC
5D-9 F101
3.15A/
250V
CON
C106
150nF
VO
12, 13
D101
1N4937
VDL
C107
10µF
R105
7.5k
C201
2200µF
35V
R106
27
C105
0.33µF/
50V
RT
R104
5.1k
16
JP2, 0
C112
680pF
R111
45k
C101
220uF/
450V
C202
2200µF
35V
R113 400k
VCC
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Typical Application Circuit (Half-bridge LLC Resonant Converter)
www.fairchildsemi.com
14
Usually, LLC resonant converters require large leakage inductance value. To obtain a large leakage inductance,
sectional winding method is used.
ƒ
ƒ
2
Core: EER3542 (Ae=107 mm )
Bobbin: EER3542 (Horizontal)
Figure 30. Transformer Construction
Pin (S → F)
Wire
Turns
Winding Method
Np
8→1
0.12φ×30 (Litz wire)
36
Section winding
Ns1
12 → 9
0.1φ×100 (Litz wire)
4
Section winding
Ns2
16 → 13
0.1φ×100 (Litz wire)
4
Section winding
Pin
Specification
Primary-side Inductance (Lp)
1－8
630μH ± 5%
100kHz, 1V
Primary-side Effective Leakage (Lr)
1－8
135μH ± 5%.
Short one of the secondary windings
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
Remark
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Typical Application Circuit (Continued)
www.fairchildsemi.com
15
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
Physical Dimensions
SIPMODAA09RevA
Figure 31. 9-SIP Package
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions,
specifically the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
16
FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter
© 2007 Fairchild Semiconductor Corporation
FSFR series • 1.0.3
www.fairchildsemi.com
17