April 2012
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
FSFR2100 — Fairchild Power Switch (FPS™)
for Half-Bridge Resonant Converters
Features
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)
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)
Applications
PDP and LCD TVs
Desktop PCs and Servers
Adapters
Telecom Power Supplies
Audio Power Supplies
Description
The FSFR2100 is a highly integrated power switch
designed for high-efficiency half-bridge resonant
converters. Offering everything necessary to build a
reliable and robust resonant converter, the FSFR2100
simplifies designs and improves productivity, while
improving performance. The FSFR2100 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.
The FSFR2100 can be applied to various resonant
converter topologies, such as: series resonant, parallel
resonant, and LLC resonant converters.
Related Resources
AN-4151 — Half-Bridge LLC Resonant Converter
Design Using FSFR2100 Fairchild Power Switch
(FPS)
Evaluation Board: FEBFSF R2100_D015v1
Ordering Information
Part
Number Package
Operating
Junction
Temperature
RDS(ON_MAX)
Maximum Output Power
without Heatsink
(VIN=350~400V)(1,2)
Maximum Output
Power with Heatsink
(VIN=350~400V)(1,2)
FSFR2100 9-SIP -40 to +130°C 0.38Ω 200W 450W
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.
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 2
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Application Circuit Diagram
Rsense
Control
IC
CDL
VCC VDL
LVcc
RT
CON
CS
SG PG
VCTR
HVCC
Cr
Llk
Lm
Ns
Vo
D1
D2 RF
CF
Np Ns
KA431
VIN
Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter)
Block Diagram
1.5
s
μ
Figure 2. Internal Block Diagram
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 3
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Pin Configuration
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 No connection.
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.
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 4
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Absolute Maximum Ratings
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 Parameter Min. Max. Unit
VDS Maximum Drain-to-Source Voltage (VDL-VCTR and VCTR-PG) 600 V
LVCC Low-Side Supply Voltage -0.3 25.0 V
HVCC to VCTR High-Side VCC Pin to Low-side Drain Voltage -0.3 25.0 V
HVCC High-Side Floating Supply Voltage -0.3 625.0 V
VCON Control Pin Input Voltage -0.3 LVCC V
VCS Current Sense (CS) Pin Input Voltage -5.0 1.0 V
VRT R
T Pin Input Voltage -0.3 5.0 V
dVCTR/dt Allowable Low-Side MOSFET Drain Voltage Slew Rate 50 V/ns
PD Total Power Dissipation(3) 12 W
TJ Maximum Junction Temperature(4) +150
°C
Recommended Operating Junction Temperature(4) -40 +130
TSTG Storage Temperature Range -55 +150 °C
MOSFET Section
VDGR Drain Gate Voltage (RGS=1MΩ) 600 V
VGS Gate Source (GND) Voltage ±30 V
IDM Drain Current Pulsed(5) 33 A
ID Continuous Drain Current TC=25°C 11
A
TC=100°C 7
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.
5. Pulse width is limited by maximum junction temperature.
Thermal Impedance
TA=25°C unless otherwise specified.
Symbol Parameter Value Unit
θJC Junction-to-Case Center Thermal Impedance (Both MOSFETs Conducting) 10.44 ºC/W
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 5
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Electrical Characteristics
TA=25°C unless otherwise specified.
Symbol Parameter Test Conditions Min. Typ. Max. Unit
MOSFET Section
BVDSS Drain-to-Source Breakdown Voltage
ID=200μA, TA=25°C 600
V
ID=200μA, TA=125°C 650
RDS(ON) On-State Resistance VGS=10V, ID=5.5A 0.32 0.38
Ω
trr Body Diode Reverse Recovery Time(6) V
GS=0V, IDiode=11.0A 120 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
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 3.2 V
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 0.5 V
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
RT=5.2KΩ
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 fSS=fOSC+40kHz, RT=5.2KΩ 140 KHz
tSS Internal Soft-Start Time 2 3 4 ms
Continued on the following page…
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 6
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Electrical Characteristics (Continued)
TA=25°C unless otherwise specified.
Symbol Parameter Test Conditions Min. Typ. Max. Unit
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
tBAO AOCP Blanking Time(6) VCS < VAOCP; ΔV/Δt=-0.1V/µs 50 ns
VOCP OCP Threshold Voltage V/Δt=-1V/µs -0.64 -0.58 -0.52 V
tBO OCP Blanking Time(6) VCS < VOCP; ΔV/Δt=-1V/µs 1.0 1.5 2.0 μs
tDA Delay Time (Low Side) Detecting from
VAOCP to Switch Off(6) ΔV/Δt=-1V/µs 250 400 ns
TSD Thermal Shutdown Temperature(6) 110 130 150
°C
ISU Protection Latch Sustain LVCC Supply
Current LVCC=7.5V 100 150 μA
VPRSET Protection Latch Reset LVCC Supply
Voltage 5 V
Dead-Time Control Section
DT Dead Time(7) 350 ns
Notes:
6. This parameter, although guaranteed, is not tested in production.
7. These parameters, although guaranteed, are tested only in EDS (wafer test) process.
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 7
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Typical Performance Characteristics
These characteristic graphs are normalized at TA=25ºC.
0.9
0.95
1
1.05
1.1
-50 -25 0 25 50 75 100
Temp (
O
C)
Normalized at 25
O
C
Temp (
O
C)
0.9
0.95
1
1.05
1.1
-50-250 255075100
Normalized at 25
O
C
Figure 4. Low-Side MOSFET Duty Cycle
vs. Temperature
Figure 5. Switching Frequency vs. Temperature
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (
O
C)
Normalized at 25
O
C
0.9
0.95
1
1.05
1.1
-50 -25 0 25 50 75 100
Temp (
O
C)
Normalized at 25
O
C
Figure 6. High-Side VCC (H
V
CC) Start
vs. Temperature
Figure 7. High-Side VCC (H
V
CC) Stop
vs. Temperature
0.9
0.95
1
1.05
1.1
-50 -25 0 25 50 75 100
Temp (
O
C)
Normalized at 25
O
C
0.9
0.95
1
1.05
1.1
-50 -25 0 25 50 75 100
Temp (
O
C)
Normalized at 25
O
C
Figure 8. Low-Side VCC (L
V
CC) Start
vs. Temperature
Figure 9. Low-Side
V
CC (L
V
CC) Stop
vs. Temperature
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 8
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Typical Performance Characteristics (Continued)
These characteristic graphs are normalized at TA=25ºC.
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (
O
C)
Normalized at 25
O
C
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (
O
C)
Normalized at 25
O
C
Figure 10. OLP Delay Current
vs. Temperature
Figure 11. OLP Protection Voltage
vs. Temperature
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (OC)
Normalized at 25OC
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (
O
C)
Normalized at 25
O
C
Figure 12. L
V
CC OVP Voltage vs. Temperature Figure 13. RT
V
oltage vs. Temperature
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (OC)
Normalized at 25OC
0.9
0.95
1
1.05
1.1
-50-250 255075100
Temp (
O
C)
Normalized at 25
O
C
Figure 14. CON Pin Enable Voltage
vs. Temperature
Figure 15. OCP Voltage vs. Temperature
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 9
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Functional Description
1. Basic Operation
FSFR2100 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.
Figure 16. MOSFETs Gate Drive Signal
2. Internal Oscillator
FSFR2100 employs a current-controlled 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 17. Current Controlled Oscillator
3. Frequency Setting
Figure 18 shows a 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.
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Gain
140 150
60 70 80 90 100 110 120 130
freq (kHz)
f min f normal f max f ISS
Soft-start
Figure 18. Resonant Converter Typical Gain Curve
Figure 19. Frequency Control Circuit
The minimum switching frequency is determined as:
min
min
5.2 100( )
k
f
kHz
R
Ω
(1)
Assuming the saturation voltage of opto-coupler
transistor is 0.2V, the maximum switching frequency is
determined as:
max
min max
5.2 4.68
( ) 100( )
kk
f
kHz
RR
ΩΩ
=+ × (2)
To prevent excessive inrush current and overshoot of
output voltage during startup, 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
from an initial high frequency (fISS) until the output
voltage is established. The soft-start circuit is made by
connecting R-C series network on the RT pin, as shown
Control
IC
VDL
LVcc
RT
CON
SG PG
R
min
R
max
C
ss
R
ss
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 10
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
in Figure 19. FSFR2100 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:
min
5.2 5.2
( ) 100 40 ( )
ISS
SS
kk
f
kHz
RR
ΩΩ
=+×+ (3)
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:
SS SS SS
TRC=⋅ (4)
f
s
time
Control loop
take over
40kHz
f
ISS
Figure 20. Frequency Sweeping of Soft-start
4. Control Pin
The FSFR2100 has a control pin for protection, cycle
skipping, and remote on/off. Figure 21 shows the internal
block diagram for control pin.
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: FSFR2100 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:
(5)
Figure 22. Control Pin Configuration for Pulse
Skipping
Remote On / Off: When an auxiliary power supply is
used for standby, the main power stage using FSFR2100
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.
Figure 23. Remote On / Off Circuit
()
kHz100x
Rk16.4
Rk2.5
maxmin
SKIP
+=
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 11
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
5. Current Sensing
Current Sensing Using Resistor: FSFR2100 senses
drain current as a negative voltage, as shown in Figure
24 and Figure 25. Half-wave sensing allows low power
dissipation in the sensing resistor, while full-wave
sensing has less switching noise in the sensing signal.
Figure 24. Half-Wave Sensing
Figure 25. Full-Wave Sensing
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
capacitor voltage (Vcrp-p) is proportional to the resonant
current in the primary side (Ipp-p) as:
2
p
p
p
pp
Cr
r
I
V
f
C
π
= (6)
To minimize power dissipation, a capacitive voltage
divider is generally used for capacitor voltage sensing, as
shown in Figure 26.
Control
IC
SG PG Ns
Np
Ns
Cr
Ip
CON
100
CB
CSENSE
Cd
VSENSE
Rd
RT
Ip
VCr
Vsense
VCrp-p
Vsensepk
delay d d
TRC=
pk
sense B
pp
Cr sense B
VC
VCC
=+2
pk
sense CON
VV=
VCON
Vsensepk
Figure 26. Current Sensing Using Resonant
Capacitor Voltage
6. Protection Circuits
The FSFR2100 has several self-protective functions,
such as Overload Protection (OLP), Over-Current
Protection (OCP), Abnormal Over-Current 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 27.
6.1 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.
Control
IC
CS
SG PG
Ns
Np Ns
Rsense
Ids
Cr
Ids
VCS
VCS
Control
IC
CS
SG PG
Rsense
Ids
VCS
Ids
VCS
Ns
Np Ns
Cr
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 12
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
6.2 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.
Figure 27. Protection Blocks
6.3 Over-Current Protection (OCP): When the
sensing pin voltage drops below -0.58V, OCP is triggered
and the MOSFETs remain off. This protection has a
shutdown time delay of 1.5µs to prevent premature
shutdown during startup.
6.4 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
drops below -0.9V. This protection is latch mode and
reset when LVCC is pulled down below 5V.
6.5 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 26 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:
2( ) pp
B
CON Cr
Bsense
C
VV
CC
=+
(7)
where VCrp-p is the amplitude of the resonant capacitor
voltage.
6.6 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.
6.7 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.
7. PCB Layout Guidelines
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 turn-on 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.
Figure 28. Example for Duty Balancing
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 13
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Typical Application Circuit (Half-Bridge LLC Resonant Converter)
Application FPS™ Device Input Voltage Range Rated Output Power Output Voltage
(Rated Current)
LCD TV FSFR2100 390VDC
(340~400VDC) 200W 24V-8.3A
Features
High efficiency ( >94% at 400VDC input)
Reduced EMI noise through zero-voltage-switching (ZVS)
Enhanced system reliability with various protection functions
Figure 29. Typical Application Circuit
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 14
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Typical Application Circuit (Continued)
Usually, LLC resonant converters require large leakage inductance value. To obtain a large leakage inductance,
sectional winding method is used.
Core: EC35 (Ae=106 mm2)
Bobbin: EC35 (Horizontal)
Transformer Model Number: SNX-2468-1
Figure 30. Transformer Construction
Pin(S F) Wire Turns Note
Np 6 2 0.08φ×88 (Litz Wire) 36
Ns1 12 9 0.08φ×234 (Litz Wire) 4 Bifilar winding
Ns2 10 13 0.08φ×234 (Litz Wire) 4 Bifilar winding
Pins Specifications Remark
Primary-Side Inductance (Lp) 26 550μH ± 10% 100kHz, 1V
Primary-Side Effective Leakage (Lr) 26 110μH ± 10% Short one of the secondary windings
For more detailed inf ormation regar ding the tr ansfor mer, visit http://www.santronics-usa.com/documents.html or contact
sales@santronics-usa.com or +1-408-734- 1878 (Sunnyvale, California USA).
© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 15
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters
Physical Dimensions
Figure 31. 9-Lead, SIP Module, Formed, Lead, 3.2X10.5X26mm
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 www.fairchildsemi.com
FSFR2100 • Rev.1.0.9 16
FSFR2100 — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters