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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
June 2010
FSFR-Series -- Fairchild Power Switch (FPSTM)
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 UniFETTMs with Fast-Recovery Type Body Diode (trr<160ns). 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)
Description
The FSFR-series include highly integrated power switches designed for high-efficiency half-bridge resonant converters. Offering everything necessary to build a reliable and robust resonant converter, the FSFRseries 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. The FSFR-series can be applied to various resonant converter topologies, such as: series resonant, parallel resonant, and LLC resonant converters.
Applications
PDP and LCD TVs Desktop PCs and Servers Adapters Telecom Power Supplies Audio Power Supplies
Related Resources
AN-4151 -- Half-Bridge LLC Resonant Converter Design TM Using FSFR-Series Fairchild Power Switch (FPS )
Ordering Information
Part Number
FSFR2100U FSFR2000 FSFR1900 FSFR1800 FSFR1700 FSFR1600 FSFR1800L FSFR1700L FSFR1600L 9-SIP(L-Forming) 9-SIP -40 to +130C
Package
Operating Junction Temperature
RDS(ON_MAX)
0.51 0.67 0.85 0.95 1.25 1.55 0.95 1.25 1.55
Maximum Output Power without Heatsink (1,2) (VIN=350~400V)
180W 160W 140W 120W 100W 80W 120W 100W 80W
Maximum Output Power with Heatsink (1,2) (VIN=350~400V)
400W 350W 300W 260W 200W 160W 260W 200W 160W
Notes: 1. The junction temperature can limit the maximum output power. 2. Maximum practical continuous power in an open-frame design at 50C ambient.
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com
FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Application Circuit Diagram
Cr Llk VCC
RT LVcc VDL HVCC
D1
Np
Ns
Vo
Lm Ns
CDL VIN
CON
Control IC
D2
VCTR KA431
CF RF
CS SG PG
Rsense
Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter)
Block Diagram
1.5 s
Figure 2. Internal Block Diagram
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Pin Configuration
1 VDL
2 3 4 56 7
8
9 HVcc
RT SG LVcc CON CS PG
10 VCTR
Figure 3. Package Diagram
Pin Definitions
Pin #
1 2
Name
VDL CON
Description
This is the drain of the high-side MOSFET, typically connected to the input DC link voltage. 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. This pin programs the switching frequency. Typically, an opto-coupler is connected to control the switching frequency for the output voltage regulation. This pin senses the current flowing through the low-side MOSFET. Typically, negative voltage is applied on this pin. This pin is the control ground. This pin is the power ground. This pin is connected to the source of the low-side MOSFET. This pin is the supply voltage of the control IC. No connection. This is the supply voltage of the high-side gate-drive circuit IC. This is the drain of the low-side MOSFET. Typically, a transformer is connected to this pin.
3 4 5 6 7 8 9 10
RT CS SG PG LVCC NC HVCC VCTR
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
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=25C unless otherwise specified.
Symbol
VDS LVCC HVCC VCON VCS VRT dVCTR/dt Low-Side Supply Voltage
Parameter
Maximum Drain-to-Source Voltage (VDL-VCTR and VCTR-PG)
Min.
500 -0.3 -0.3 -0.3 -0.3 -5.0 -0.3 FSFR2100U FSFR2000 FSFR1900 FSFR1800 FSFR1700 FSFR1600
Max.
25.0 25.0 525.0 LVCC 1.0 5.0 50 12.0 12.0 11.8 11.7 11.6 11.5 +150
Unit
V V V V V V V V/ns
HVCC to VCTR High-Side VCC Pin to Low-Side Drain Voltage High-Side Floating Supply Voltage Control Pin Input Voltage Current Sense (CS) Pin Input Voltage RT Pin Input Voltage Allowable Low-Side MOSFET Drain Voltage Slew Rate
PD
Total Power Dissipation
(3)
W
TJ TSTG VDGR VGS
Maximum Junction Temperature Storage Temperature Range Drain Gate Voltage (RGS=1M) Gate Source (GND) Voltage
(4) (4)
Recommended Operating Junction Temperature
-40 -55 500
+130 +150
C C V
MOSFET Section 30 FSFR2100U FSFR2000 IDM Drain Current Pulsed
(5)
V
32 31 26 23 20 18 Continued on the following page... A
FSFR1900 FSFR1800 FSFR1700 FSFR1600
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Absolute Maximum Ratings (Continued)
Symbol
MOSFET Section (Continued) FSFR2100U FSFR2000 FSFR1900 ID Continuous Drain Current FSFR1800 FSFR1700 FSFR1600 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. TC=25C TC=100C TC=25C TC=100C TC=25C TC=100C TC=25C TC=100C TC=25C TC=100C TC=25C TC=100C 10.5 6.5 9.5 6.0 8.0 5.0 7.0 4.5 6.0 3.9 4.5 2.7 A
Parameter
Min.
Max.
Unit
Thermal Impedance
TA=25C unless otherwise specified.
Symbol
Parameter
FSFR2100U FSFR2000
Value
10.44 10.44 10.56 10.68 10.79 10.89
Unit
JC
Junction-to-Case Center Thermal Impedance (Both MOSFETs Conducting)
FSFR1900 FSFR1800 FSFR1700 FSFR1600
C/W
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Electrical Characteristics
TA=25C unless otherwise specified.
Symbol
MOSFET Section BVDSS
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
Drain-to-Source Breakdown Voltage
ID=200A, TA=25C ID=200A, TA=125C
500 540 0.41 0.53 0.74 0.77 1.00 1.25 0.51 0.67 0.85 0.95 1.25 1.55
V
FSFR2100U VGS=10V, ID=6.0A FSFR2000 RDS(ON) On-State Resistance FSFR1900 FSFR1800 FSFR1700 FSFR1600 VGS=10V, ID=5.0A VGS=10V, ID=4.0A VGS=10V, ID=3.0A VGS=10V, ID=2.0A VGS=10V, ID=2.25A dIDiode/dt=100A/s FSFR2100U VGS=0V, IDiode=12.0A FSFR2000 trr Body Diode Reverse (6) Recovery Time FSFR1900 FSFR1800 FSFR1700 FSFR1600 Supply Section ILK IQHVCC IQLVCC IOHVCC IOLVCC Offset Supply Leakage Current Quiescent HVCC Supply Current Quiescent LVCC Supply Current Operating HVCC Supply Current (RMS Value) Operating LVCC Supply Current (RMS Value) H-VCC=VCTR=600V/500V (HVCCUV+) - 0.1V (LVCCUV+) - 0.1V fOSC=100KHz, VCON > 0.6V No Switching, VCON < 0.4V fOSC=100KHz, VCON > 0.6V No Switching, VCON < 0.4V VGS=0V, IDiode=9.5A VGS=0V, IDiode=8.0A VGS=0V, IDiode=7.0A VGS=0V, IDiode=6.0A VGS=0V, IDiode=5.0A
120 125 140 160 160 65 ns
50 50 100 6 100 7 2 120 200 9 200 11 4
A A A mA A mA mA
Continued on the following page...
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Electrical Characteristics (Continued)
TA=25C unless otherwise specified. Symbol UVLO Section LVCCUV+ LVCCUVLVCCUVH HVCCUV+ HVCCUVHVCCUVH LVCC Supply Under-Voltage Positive Going Threshold (LVCC Start) LVCC Supply Under-Voltage Negative Going Threshold (LVCC Stop) LVCC Supply Under-Voltage Hysteresis HVCC Supply Under-Voltage Positive Going Threshold (HVCC Start) HVCC Supply Under-Voltage Negative Going Threshold (HVCC Stop) HVCC Supply Under-Voltage Hysteresis 8.2 7.8 13.0 10.2 14.5 11.3 3.2 9.2 8.7 0.5 10.2 9.6 16.0 12.4 V V V V V V Parameter Test Conditions Min. Typ. Max. Unit
Oscillator & Feedback Section VCONDIS VCONEN VRT fOSC DC fSS tSS Control Pin Disable Threshold Voltage Control Pin Enable Threshold Voltage V-I Converter Threshold Voltage Output Oscillation Frequency Output Duty Cycle Internal Soft-Start Initial Frequency Internal Soft-Start Time fSS=fOSC+40kHz, RT=5.2K 2 RT=5.2K 0.36 0.54 1.5 94 48 0.40 0.60 2.0 100 50 140 3 4 0.44 0.66 2.5 106 52 V V V KHz % KHz ms
Protection Section IOLP VOLP VOVP VAOCP tBAO VOCP tBO tDA TSD ISU VPRSET OLP Delay Current OLP Protection Voltage LVCC Over-Voltage Protection AOCP Threshold Voltage AOCP Blanking Time
(6)
VCON=4V VCON > 3.5V L-VCC > 21V V/t=-0.1V/s VCS < VAOCP; V/t=-0.1V/s V/t=-1V/s VCS < VOCP; V/t=-1V/s V/t=-1V/s
3.6 4.5 21 -1.0
4.8 5.0 23 -0.9 50
6.0 5.5 25 -0.8
A V V V ns
OCP Threshold Voltage OCP Blanking Time
(6)
-0.64 1.0
-0.58 1.5 250
-0.52 2.0 400 150 150
V s ns C A V
Delay Time (Low Side) Detecting from (6) VAOCP to Switch Off Thermal Shutdown Temperature
(6)
110 LVCC=7.5V 5
130 100
Protection Latch Sustain LVCC Supply Current Protection Latch Reset LVCC Supply Voltage
(7)
Dead-Time Control Section DT Dead Time 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.
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Typical Performance Characteristics
These characteristic graphs are normalized at TA=25C.
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
1
1
0.95
0.95
0.9 -50 -25 0 25 50 75 100
0.9 -50 -25 0 25 50 75 100
Temp
(OC)
Temp (OC)
Figure 4. Low-Side MOSFET Duty Cycle
vs. Temperature
1.1
Figure 5. Switching Frequency vs. Temperature
1.1
1.05
1.05
1
Normalized at 25OC
-50 -25 0 25 50 75 100
Normalized at 25OC
1
0.95
0.95
0.9
0.9 -50 -25 0 25 50 75 100
Temp (OC)
Temp (OC)
Figure 6. High-Side VCC (HVCC) Start vs. Temperature
1.1
Figure 7. High-Side VCC (HVCC) Stop vs. Temperature
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
1
1
0.95
0.95
0.9 -50 -25 0 25 50 75 100
0.9 -50 -25 0 25 50 75 100
Temp (OC)
Temp (OC)
Figure 8. Low-Side VCC (LVCC) Start vs. Temperature
Figure 9. Low-Side VCC (LVCC) Stop vs. Temperature
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Typical Performance Characteristics (Continued)
These characteristic graphs are normalized at TA=25C.
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
1
1
0.95
0.95
0.9 -50 -25 0 25 50 75 100
0.9 -50 -25 0 25 50 75 100
Temp (OC)
Temp (OC)
Figure 10. OLP Delay Current vs. Temperature
1.1
1.1
Figure 11. OLP Protection Voltage
vs. Temperature
1.05
1.05
Normalized at 25OC
1
Normalized at 25OC
-50 -25 0 25 50 75 100
1
0.95
0.95
0.9
0.9 -50 -25 0 25 50 75 100
Temp (OC)
Temp (OC)
Figure 12. LVCC OVP Voltage vs. Temperature
1.1
Figure 13. RT Voltage vs. Temperature
1.1
1.05
1.05
Normalized at 25OC
1
Normalized at 25OC
-50 -25 0 25 50 75 100
1
0.95
0.95
0.9
0.9 -50 -25 0 25 50 75 100
Temp (OC)
Temp (OC)
Figure 14. CON Pin Enable Voltage vs. Temperature
Figure 15. OCP Voltage vs. Temperature
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Functional Description
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.
Dead time
Gain
1.8
f min
1.6
f normal
f max
f ISS
High side MOSFET gate drive
1.4
1.2
Low side MOSFET gate drive
time
1.0
Soft-start
0.8
Figure 16. MOSFETs Gate Drive Signal
0.6
60 70 80 90 100 110
freq (kHz)
120
130
140
150
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 =
5.2k x 100(kHz ) Rmin
(1)
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 optocoupler transistor is connected to the RT pin to modulate the switching frequency.
Assuming the saturation voltage of opto-coupler transistor is 0.2V, the maximum switching frequency is determined as:
f max = (
5.2k 4.68k + ) x 100( kHz ) Rmin Rmax
(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 ISS from an initial high frequency (f ) until the output voltage is established. The soft-start circuit is made by connecting R-C series network on the RT pin, as shown
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 10
FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
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:
f ISS = (
5.2k 5.2k + ) x 100 + 40 (kHz ) Rmin RSS
(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:
TSS = RSS CSS
fs f ISS
(4)
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 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.
40kHz
Control loop take over
OP1
Main Output
R1
time
Figure 20. Frequency Sweeping of Soft-start
FPS
C1
Main Off
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.
RT
Rmin
Aux Output
CON
OP1
Figure 23. Remote On / Off Circuit
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
4. Current Sensing Method Current Sensing Using Resistor: FSFR-series 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.
=
5 .2 k 4.16 k + R min R max
x100(kHz)
(5)
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Cr
Np
Ns
Ns Control IC VCS
CS SG PG
Ids
Rsense
Ids
VCS
Figure 24. Half-Wave Sensing
Ids
Ip
VCr VCrp-p
VCS
Vsense
Cr VCS
CS
300~500k
Vsense pk CB = VCr p - p Csense + CB
Vsense pk = VCON 2
Control IC Np Ns
Vsensepk VCON Vsensepk
SG
PG
Rsense
Ns
Tdelay = Rd Cd
Ids
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 p-p capacitor voltage (Vcr ) is proportional to the resonant p-p current in the primary side (Ip ) as:
Figure 26. Current Sensing Using Resonant Capacitor Voltage 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 27. 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.
VCr
p- p
=
I p p- p 2 f sCr
(6)
To minimize power dissipation, a capacitive voltage divider is generally used for capacitor voltage sensing, as shown in Figure 26.
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FSFR-Series -- Fairchild Power Switch (FPSTM) 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.
LVCC
7
+
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 FPSTM 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 130C, the thermal shutdown triggers.
LVCC good
VREF
11 / 14 V
-
Internal Bias
Shutdown OCP OLP OVP LVCC good CON 20k Auto-restart protection
S R Q -Q
Latch protection
Q -Q S R
AOCP
F/F
F/F
TSD LVCC < 5V
Figure 27. Protection Blocks
5.1 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 1.5s to prevent premature shutdown during startup. 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 drops below -0.9V. This protection is latch mode and reset when LVCC is pulled down below 5V. 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 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:
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.
Figure 28. Example for Duty Balancing
VCON =
CB VCr p - p 2(C B + C sense )
p-p
(7)
where VCr voltage.
is the amplitude of the resonant capacitor
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Typical Application Circuit (Half-Bridge LLC Resonant Converter)
Application
LCD TV
FPSTM Device
FSFR2100U
Input Voltage Range
400V (20ms Hold-up Time)
Rated Output Power
192W
Output Voltage (Rated Current)
24V-8A
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
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
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: EER3542 (Ae=107 mm ) Bobbin: EER3542 (Horizontal)
EC35 Np
2
2
13 N s2 12 N 10
s1
6
9
Figure 30. Transformer Construction
Pins (S F)
Np Ns1 Ns2 81 12 9 16 13
Wire
0.12x30 (Litz Wire) 0.1x100 (Litz Wire) 0.1x100 (Litz Wire)
Turns
36 4 4
Note
Bifilar Winding Bifilar Winding
Pins
Primary-Side Inductance (Lp) Primary-Side Effective Leakage (Lr) 18 18
Specifications
630H 5% 135H 5%
Remark
100kHz, 1V Short One of the secondary Windings
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Physical Dimensions
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/.
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
Physical Dimensions
Figure 32. 9-Lead, SIP Module, L-Forming, 3.2x10.5x26mm Body
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/.
(c) 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9
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FSFR-Series -- Fairchild Power Switch (FPSTM) for Half-Bridge Resonant Converter
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