FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converters Features Description Variable Frequency Control with 50% Duty Cycle for Half-bridge Resonant Converter Topology High Efficiency through Zero Voltage Switching (ZVS) Fixed Dead Time (350ns) Optimized for MOSFETs Remote On/Off Control Using Control Pin 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. Internal UniFET™s with Fast-Recovery Type Body Diode (trr<160ns). Up to 300kHz Operating Frequency Pulse Skipping for Frequency Limit (Programmable) at Light-Load Condition Protection Functions: Over-Voltage Protection (OVP), Over-Load Protection (OLP), Over-Current Protection (OCP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) Applications The FSFR-series can be applied to various resonant converter topologies, such as: series resonant, parallel resonant, and LLC resonant converters. PDP and LCD TVs Desktop PCs and Servers Adapters Related Resources Telecom Power Supplies AN-4151 — Half-Bridge LLC Resonant Converter Design ™ Using FSFR-Series Fairchild Power Switch (FPS ) Audio Power Supplies Ordering Information RDS(ON_MAX) Maximum Output Power without Heatsink (1,2) (VIN=350~400V) Maximum Output Power with Heatsink (1,2) (VIN=350~400V) FSFR2100U 0.51Ω 180W 400W FSFR2000 0.67Ω 160W 350W FSFR1900 0.85Ω 140W 300W 0.95Ω 120W 260W 1.25Ω 100W 200W Part Number FSFR1800 Package Operating Junction Temperature 9-SIP FSFR1700 -40 to +130°C FSFR1600 1.55Ω 80W 160W FSFR1800L 0.95Ω 120W 260W 1.25Ω 100W 200W 1.55Ω 80W 160W FSFR1700L 9-SIP(L-Forming) FSFR1600L 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 FSFR series Rev.1.0.9 www.fairchildsemi.com FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter June 2010 D1 Cr Llk LVcc VCC Np HVCC Lm Ns RT CON CDL VIN Vo Ns VDL Control IC D2 CF RF VCTR KA431 CS SG PG Rsense Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter) Block Diagram 1.5μ s Figure 2. Internal Block Diagram © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 2 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Application Circuit Diagram 1 2 3 4 5 6 7 VDL 8 RT SG LVcc CON CS PG 9 10 VCTR HVcc Figure 3. Package Diagram Pin Definitions Pin # Name 1 VDL Description 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 No connection. 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 FSFR series Rev.1.0.9 www.fairchildsemi.com 3 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Pin Configuration 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) Low-Side Supply Voltage HVCC to VCTR High-Side VCC Pin to Low-Side Drain Voltage Max. 500 Unit V -0.3 25.0 V -0.3 25.0 V HVCC High-Side Floating Supply Voltage -0.3 525.0 V 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 TJ TSTG Allowable Low-Side MOSFET Drain Voltage Slew Rate Total Power Dissipation (3) Maximum Junction Temperature FSFR2100U 12.0 FSFR2000 12.0 FSFR1900 11.8 FSFR1800 11.7 FSFR1700 11.6 FSFR1600 11.5 (4) +150 (4) Recommended Operating Junction Temperature -40 +130 Storage Temperature Range -55 +150 W °C °C MOSFET Section VDGR Drain Gate Voltage (RGS=1MΩ) VGS Gate Source (GND) Voltage IDM Drain Current Pulsed 500 V ±30 (5) FSFR2100U 32 FSFR2000 31 FSFR1900 26 FSFR1800 23 FSFR1700 20 FSFR1600 18 V A Continued on the following page… © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 4 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Absolute Maximum Ratings Symbol Parameter Min. Max. Unit MOSFET Section (Continued) FSFR2100U FSFR2000 FSFR1900 ID Continuous Drain Current FSFR1800 FSFR1700 FSFR1600 TC=25°C 10.5 TC=100°C 6.5 TC=25°C 9.5 TC=100°C 6.0 TC=25°C 8.0 TC=100°C 5.0 TC=25°C 7.0 TC=100°C 4.5 TC=25°C 6.0 TC=100°C 3.9 TC=25°C 4.5 TC=100°C 2.7 A 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 θJC Parameter Junction-to-Case Center Thermal Impedance (Both MOSFETs Conducting) © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 Value FSFR2100U 10.44 FSFR2000 10.44 FSFR1900 10.56 FSFR1800 10.68 FSFR1700 10.79 FSFR1600 10.89 Unit ºC/W www.fairchildsemi.com 5 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Absolute Maximum Ratings (Continued) TA=25°C unless otherwise specified. Symbol Parameter Test Conditions Min. Typ. Max. Unit MOSFET Section BVDSS RDS(ON) Drain-to-Source Breakdown Voltage On-State Resistance ID=200μA, TA=25°C ID=200μA, TA=125°C 500 V 540 FSFR2100U VGS=10V, ID=6.0A 0.41 0.51 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 FSFR1600 VGS=10V, ID=2.25A 1.25 1.55 Ω dIDiode/dt=100A/μs trr Body Diode Reverse (6) Recovery Time FSFR2100U VGS=0V, IDiode=12.0A 120 FSFR2000 VGS=0V, IDiode=9.5A 125 FSFR1900 VGS=0V, IDiode=8.0A 140 FSFR1800 VGS=0V, IDiode=7.0A 160 FSFR1700 VGS=0V, IDiode=6.0A 160 FSFR1600 VGS=0V, IDiode=5.0A 65 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 Continued on the following page… © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 6 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Electrical Characteristics TA=25°C unless otherwise specified. Symbol Parameter Test Conditions Min. Typ. Max. Unit 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 UVLO Section 3.2 V 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 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 140 fSS=fOSC+40kHz, RT=5.2KΩ 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 (6) tBAO AOCP Blanking Time VCS < VAOCP; ΔV/Δt=-0.1V/µs VOCP OCP Threshold Voltage V/Δt=-1V/µs (6) tBO OCP Blanking Time VCS < VOCP; ΔV/Δt=-1V/µs tDA Delay Time (Low Side) Detecting from (6) VAOCP to Switch Off ΔV/Δt=-1V/µs TSD Thermal Shutdown Temperature ISU Protection Latch Sustain LVCC Supply Current VPRSET (6) 50 ns -0.64 -0.58 -0.52 V 1.0 1.5 2.0 μs 250 400 ns 130 150 °C 100 150 μA 110 LVCC=7.5V Protection Latch Reset LVCC Supply Voltage 5 V Dead-Time Control Section DT (7) 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. © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 7 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Electrical Characteristics (Continued) 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 Temp 50 75 -50 100 -25 0 25 50 75 100 Temp (OC) (OC) Figure 4. Low-Side MOSFET Duty Cycle Figure 5. Switching Frequency vs. Temperature 1.1 1.1 1.05 1.05 Normalized at 25OC Normalized at 25OC vs. Temperature 1 0.95 0.9 -50 -25 0 25 50 75 1 0.95 0.9 100 -50 -25 0 Temp (OC) Figure 6. High-Side VCC (HVCC) Start vs. Temperature 50 75 100 Figure 7. High-Side VCC (HVCC) Stop vs. Temperature 1.1 1.1 1.05 1.05 Normalized at 25OC Normalized at 25OC 25 Temp (OC) 1 0.95 1 0.95 0.9 0.9 -50 -25 0 25 50 75 -50 100 -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 © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 8 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Typical Performance Characteristics 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 25 50 75 100 Temp (OC) Temp (OC) Figure 10. OLP Delay Current vs. Temperature Figure 11. OLP Protection Voltage 1.1 1.1 1.05 1.05 Normalized at 25OC Normalized at 25OC vs. Temperature 1 0.95 0.9 0.95 0.9 -50 -25 0 25 50 75 100 -50 -25 0 25 50 75 100 Temp (OC) Temp (OC) Figure 12. LVCC OVP Voltage vs. Temperature Figure 13. RT Voltage vs. Temperature 1.1 1.1 1.05 1.05 Normalized at 25OC Normalized at 25OC 1 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 14. CON Pin Enable Voltage vs. Temperature Figure 15. OCP Voltage vs. Temperature © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 9 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Typical Performance Characteristics (Continued) 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 normal f max f ISS 1.6 Dead time High side MOSFET gate drive 1.4 1.2 1.0 Low side MOSFET gate drive Soft-start 0.8 time Figure 16. MOSFETs Gate Drive Signal 0.6 60 70 80 90 100 110 120 130 140 150 freq (kHz) Figure 18. Resonant Converter Typical Gain Curve 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. 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 optocoupler transistor is connected to the RT pin to modulate the switching frequency. 5.2k Ω × 100(kHz ) Rmin (1) 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 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 © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 10 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Functional Description f ISS = ( 5.2k Ω 5.2k Ω + ) × 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 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 OP1 Main Output R1 time C1 Figure 20. Frequency Sweeping of Soft-start Main Off FPS 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 Aux Output Rmin CON OP1 Figure 23. Remote On / Off Circuit 4. Current Sensing Method Figure 21. Internal Block of Control Pin 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. 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 x100(kHz) © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 (5) www.fairchildsemi.com 11 FSFR-Series — Fairchild Power Switch (FPS™) 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: Np Ns 300~500kΩ Ns Control IC VCS Ids CS SG PG Rsense VCS Ids Ip Figure 24. Half-Wave Sensing Ids VCr VCrp-p VCS Vsense Vsense pk CB = VCr p − p Csense + CB Vsense pk = VCON 2 Cr Vsensepk Control IC VCS Np CS VCON Ns Vsensepk PG SG Rsense Ns Tdelay = Rd Cd Ids Figure 26. Current Sensing Using Resonant Capacitor Voltage Figure 25. Full-Wave Sensing 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. 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 2π f sCr 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. (6) To minimize power dissipation, a capacitive voltage divider is generally used for capacitor voltage sensing, as shown in Figure 26. © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 12 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Cr 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. LVCC 7 + LVCC good Internal Bias VREF - 11 / 14 V Shutdown OCP Auto-restart protection OLP OVP LVCC good CON 20k S Q R -Q F/F Latch protection Q S -Q R F/F 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. AOCP 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 1.5µs 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: VCON = CB VCr p − p 2(C B + C sense ) where VCr voltage. p-p Figure 28. Example for Duty Balancing (7) is the amplitude of the resonant capacitor © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 13 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. Application FPS™ Device Input Voltage Range Rated Output Power Output Voltage (Rated Current) LCD TV FSFR2100U 400V (20ms Hold-up Time) 192W 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 © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 14 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Typical Application Circuit (Half-Bridge LLC Resonant Converter) Usually, LLC resonant converters require large leakage inductance value. To obtain a large leakage inductance, sectional winding method is used. 2 Core: EER3542 (Ae=107 mm ) Bobbin: EER3542 (Horizontal) EC35 2 Np 13 N s2 12 N s1 10 6 9 Figure 30. Transformer Construction Pins (S → F) Wire Turns Note Np 8→1 0.12φ×30 (Litz Wire) 36 Ns1 12 → 9 0.1φ×100 (Litz Wire) 4 Bifilar Winding Ns2 16 → 13 0.1φ×100 (Litz Wire) 4 Bifilar Winding Pins Specifications Remark 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 Rev.1.0.9 www.fairchildsemi.com 15 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Typical Application Circuit (Continued) FSFR-Series — Fairchild Power Switch (FPS™) 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/. © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 16 FSFR-Series — Fairchild Power Switch (FPS™) 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/. © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 17 FSFR-Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter © 2007 Fairchild Semiconductor Corporation FSFR series Rev.1.0.9 www.fairchildsemi.com 18