FSFR2100XSL

FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter October 2010 FSFR-XS Series — 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 UniFET™ with Fast-Recovery Body Diode Fixed Dead Time (350ns) Optimized for MOSFETs Up to 300kHz Operating Frequency Auto-Restart Operation for All Protections with External LVCC Protection Functions: Over-Voltage Protection (OVP), Over-Current Protection (OCP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) Description The FSFR-XS series includes highly integrated power switches designed for high-efficiency half-bridge resonant converters. Offering everything necessary to build a reliable and robust resonant converter, the FSFRXS series simplifies designs while improving productivity and performance. The FSFR-XS series combines power MOSFETs with fast-recovery type body diodes, a highside 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 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 reverse recovery. Using the zero-voltage-switching (ZVS) technique dramatically reduces the switching losses and significantly improves efficiency. The ZVS also reduces the switching noise noticeably, which allows a smallsized Electromagnetic Interference (EMI) filter. The FSFR-XS series can be applied to 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 Related Resources AN4151 — Half-bridge LLC Resonant Converter Design TM Using FSFR-Series Fairchild Power Switch (FPS ) Ordering Information Part Number FSFR2100XS FSFR1800XS FSFR1700XS FSFR1600XS FSFR2100XSL FSFR1800XSL FSFR1700XSL FSFR1600XSL 9-SIP L-Forming 9-SIP -40 to +130°C Package Operating Junction Temperature RDS(ON_MAX) 0.51Ω 0.95Ω 1.25Ω 1.55Ω 0.51Ω 0.95Ω 1.25Ω 1.55Ω Maximum Output Power without Heatsink (1,2) (VIN=350~400V) 180W 120W 100W 80W 180W 120W 100W 80W Maximum Output Power with Heatsink (1,2) (VIN=350~400V) 400W 260W 200W 160W 400W 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 50°C ambient. © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Application Circuit Diagram Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter) Block Diagram Figure 2. Internal Block Diagram © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 2 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Pin Configuration Figure 3. Package Diagram Pin Definitions Pin # 1 2 3 4 5 6 7 8 9 10 Name VDL AR RT CS SG PG LVCC NC HVCC VCTR Description This is the drain of the high-side MOSFET, typically connected to the input DC link voltage. This pin is for discharging the external soft-start capacitor when any protections are triggered. When the voltage of this pin drops to 0.2V, all protections are reset and the controller starts to operate again. 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. © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 3 FSFR-XS Series — Fairchild Power Switch (FPS™) 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=25°C unless otherwise specified. Symbol VDS LVCC HVCC VAR VCS VRT dVCTR/dt Parameter Maximum Drain-to-Source Voltage (VDL-VCTR and VCTR-PG) Low-Side Supply Voltage High-Side Floating Supply Voltage Auto-Restart Pin Input Voltage Current-Sense (CS) Pin Input Voltage RT Pin Input Voltage Allowable Low-Side MOSFET Drain Voltage Slew Rate FSFR2100XS/L FSFR1800XS/L FSFR1700XS/L FSFR1600XS/L (4) (4) Min. 500 -0.3 -0.3 -0.3 -0.3 -5.0 -0.3 Max. 25.0 25.0 525.0 LVCC 1.0 5.0 50 12.0 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 PD Total Power Dissipation (3) W TJ TSTG VDGR VGS Maximum Junction Temperature Storage Temperature Range Drain Gate Voltage (RGS=1MΩ) Gate Source (GND) Voltage Recommended Operating Junction Temperature -40 -55 500 +130 +150 °C °C V MOSFET Section ±30 FSFR2100XS/L IDM Drain Current Pulsed (5) V 32 23 20 18 TC=25°C TC=100°C TC=25°C TC=100°C TC=25°C TC=100°C TC=25°C TC=100°C 5~7 10.5 6.5 7.0 4.5 6.0 3.9 4.5 2.7 kgf·cm A A FSFR1800XS/L FSFR1700XS/L FSFR1600XS/L FSFR2100XS/L FSFR1800XS/L ID Continuous Drain Current FSFR1700XS/L FSFR1600XS/L Package Section Torque Recommended Screw Torque 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. © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 4 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Thermal Impedance TA=25°C unless otherwise specified. Symbol Parameter FSFR2100XS/L FSFR1800XS/L FSFR1700XS/L FSFR1600XS/L Value 10.44 10.68 10.79 10.89 Unit θJC Junction-to-Case Center Thermal Impedance (Both MOSFETs Conducting) ºC/W Electrical Characteristics TA=25°C unless otherwise specified. Symbol MOSFET Section BVDSS Parameter Test Conditions Min. Typ. Max. Unit Drain-to-Source Breakdown Voltage ID=200μA, TA=25°C ID=200μA, TA=125°C 500 540 0.41 0.77 1.00 1.25 120 160 0.51 0.95 1.25 1.55 V FSFR2100XS/L VGS=10V, ID=6.0A RDS(ON) On-State Resistance FSFR1800XS/L VGS=10V, ID=3.0A FSFR1700XS/L VGS=10V, ID=2.0A FSFR1600XS/L VGS=10V, ID=2.25A FSFR2100XS/L FSFR1800XS/L FSFR1700XS/L FSFR1600XS/L 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) HVCC=VCTR=500V (HVCCUV+) - 0.1V (LVCCUV+) - 0.1V fOSC=100KHz No Switching fOSC=100KHz No Switching VGS=0V, IDiode=10.5A, dIDiode/dt=100A/μs VGS=0V, IDiode=7.0A, dIDiode/dt=100A/μs VGS=0V, IDiode=6.0A, dIDiode/dt=100A/μs VGS=0V, IDiode=4.5A, dIDiode/dt=100A/μs Ω trr Body Diode Reverse (6) Recovery Time ns 160 90 50 50 100 6 100 7 2 120 200 9 200 11 4 μA μA μA mA μA mA mA Continued on the following page… © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 5 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Electrical Characteristics (Continued) TA=25°C unless otherwise specified. Symbol UVLO Section LVCCUV+ LVCCUVLVCCUVH HVCCUV+ HVCCUVHVCCUVH Parameter Test Conditions Min. 11.2 8.9 Typ. 12.5 10.0 2.50 Max. 13.8 11.1 Unit V V V 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 9.2 8.7 0.5 10.2 9.6 V V V Oscillator & Feedback Section VRT fOSC DC fSS tSS V-I Converter Threshold Voltage Output Oscillation Frequency Output Duty Cycle Internal Soft-Start Initial Frequency Internal Soft-Start Time fSS=fOSC+40kHz, RT=5.2KΩ 2 RT=5.2KΩ 1.5 94 48 2.0 100 50 140 3 4 2.5 106 52 V KHz % KHz ms Protection Section VCssH VCssL VOVP VAOCP tBAO VOCP tBO tDA TSD Beginning Voltage to Discharge CSS Beginning Voltage to Charge CSS and Restart LVCC Over-Voltage Protection AOCP Threshold Voltage AOCP Blanking Time (6) 0.9 0.16 LVCC > 21V 21 -1.0 VCS < VAOCP -0.64 VCS < VOCP 1.0 1.0 0.20 23 -0.9 50 -0.58 1.5 250 1.1 0.24 25 -0.8 V V V V ns OCP Threshold Voltage OCP Blanking Time (6) -0.52 2.0 400 150 V μs ns °C Delay Time (Low Side) Detecting from (6) VAOCP to Switch Off Thermal Shutdown Temperature (7) (6) 120 135 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. © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 6 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Typical Performance Characteristics These characteristic graphs are normalized at TA=25ºC. 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 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 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 1 Normalized at 25OC 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 © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 7 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Typical Performance Characteristics (Continued) These characteristic graphs are normalized at TA=25ºC. 1.1 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 10. LVCC OVP Voltage vs. Temperature 1.1 1.1 Figure 11. RT Voltage vs. Temperature 1.05 1.05 Normalized at 25℃ 1 Normalized at 25℃ -50 -25 0 25 50 75 100 1 0.95 0.95 0.9 0.9 -50 -25 0 25 50 75 100 Temp(℃ ) Temp(℃ ) Figure 12. VCssL vs. Temperature 1.1 Figure 13. VCssH vs. Temperature 1.05 Normalized at 25OC 1 0.95 0.9 -50 -25 0 25 50 75 100 Temp (OC) Figure 14. OCP Voltage vs. Temperature © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 8 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Functional Description 1. Basic Operation. FSFR-XS 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 15. Figure 15. MOSFETs Gate Drive Signal 2. Internal Oscillator: FSFR-XS series employs a current-controlled oscillator, as shown in Figure 16. 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 the RT pin (ICTC) using a current mirror. Therefore, the switching frequency increases as ICTC increases. Figure 17. Resonant Converter Typical Gain Curve LVCC VDL RT Rmax Rmin Rss AR Css CS SG PG Figure 16. Current-Controlled Oscillator Figure 18. Frequency Control Circuit 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 in Figure 18. FSFR-XS series also has a 3ms internal soft-start 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 19. The initial frequency of the soft-start is given as: 3. Frequency Setting: Figure 17 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 18 shows the typical circuit configuration for the RT pin, where the opto-coupler transistor is connected to the RT pin to modulate the switching frequency. The minimum switching frequency is determined as: f min = 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 ISS = ( f max = ( 5.2k Ω 4.68k Ω + ) × 100( kHz ) Rmin Rmax 5.2k Ω 5.2k Ω + ) × 100 + 40 (kHz ) Rmin RSS (3) (2) © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 9 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter It is typical to set the initial frequency of soft-start two to three times the resonant frequency (fO) of the resonant network. The soft-start time is three to four times the RC time constant. The RC time constant is: (a ) (b ) ( a) (b ) (a ) (b ) L V CC V AR τ = RSS • CSS (4) ICr V C ssH V C ssL t stop tS /S (a ) P r o te ction s a r e tr igge r e d, ( b ) F S F R- U S r e sta r ts Figure 21. Self Auto-Restart Operation Figure 19. Frequency Sweeping of Soft-Start 5. Protection Circuits: The FSFR-XS series has several self-protective functions, such as Over-Current Protection (OCP), Abnormal Over-Current Protection (AOCP), OverVoltage Protection (OVP), and Thermal Shutdown (TSD). These protections are auto-restart mode protections, as shown in Figure 22. Once a fault condition is detected, switching is terminated and the MOSFETs remain off. When LVCC falls to the LVCC stop voltage of 10V or AR signal is HIGH, the protection is reset. The FSFR-XS resumes normal operation when LVCC reaches the start voltage of 12.5V. 4. Self Auto-Restart: The FSFR-XS series can restart automatically even though any built-in protections are triggered with external supply voltage. As can be seen in Figure 20 and Figure 21, once any protections are triggered, the M1 switch turns on and the V-I converter is disabled. CSS starts to discharge until VCss across CSS drops to VCssL. Then, all protections are reset, M1 turns off, and the V-I converter resumes at the same time. The FSFR-XS starts switching again with soft-start. If the protections occur while VCss is under VCssL and VCssH level, the switching is terminated immediately, VCss continues to increase until reaching VCssH, then CSS is discharged by M1. Figure 22. Protection Blocks Figure 20. Internal Block of AR Pin 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 is triggered. AOCP is triggered without shutdown delay if the sensing pin voltage drops below -0.9V. After protections trigger, FSFR-XS is disabled during the stop-time, tstop, where VCss decreases and reaches to VCssL. The stop-time of FSFR-XS can be estimated as: t STOP = C SS • {(RSS + RMIN ) || 5kΩ} The soft-start time, ts/s can be set as Equation (4). (5) © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 10 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter 5.3 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 the FPS™ is utilized. 5.4 Thermal Shutdown (TSD): The MOSFETs and the control IC in one package makes it easier for the control IC to detect the abnormal over-temperature of the MOSFETs. If the temperature exceeds approximately 130°C, thermal shutdown triggers. 6. Current Sensing Using a Resistor: FSFR-XS series senses drain current as a negative voltage, as shown in Figure 23 and Figure 24. Half-wave sensing allows low power dissipation in the sensing resistor, while full-wave sensing has less switching noise in the sensing signal. Cr 7. PCB Layout Guidelines: Duty imbalance problems may occur due to the radiated noise from the main transformer, the inequality of the secondary side leakage inductances of main transformer, and so on. This is one of the 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 turn on by turns. The magnetic fields with opposite directions induce a current through, into, or out of the RT pin, which makes the turn-on duration of each MOSFET different. It is strongly recommended to separate the control components in the vicinity of RT pin from the primary current flow pattern on PCB layout. Figure 25 shows an example for the duty-balanced case. Np Ns Ns Control IC VCS CS SG PG Ids Rsense Ids VCS Figure 25. Example for Duty Balancing Figure 23. Half-Wave Sensing Ids VCS Cr VCS CS Control IC Np Ns SG PG Rsense Ns Ids Figure 24. Full-Wave Sensing © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 11 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Physical Dimensions Figure 26. 9-Lead Single Inline Package (SIP) 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/. © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 12 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter Physical Dimensions Figure 27. 9-Lead Single Inline Package (SIP) L-Forming 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/. © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 13 FSFR-XS Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter © 2010 Fairchild Semiconductor Corporation FSFR-XS Series • Rev.1.0.1 www.fairchildsemi.com 14