FSQ0565R, FSQ0765R Green-Mode Fairchild Power Switch (FPS™) for Quasi-Resonant Operation - Low EMI and High Efficiency Features Description Optimized for Quasi-Resonant Converter (QRC) A Quasi-Resonant Converter (QRC) generally shows lower EMI and higher power conversion efficiency than a conventional hard-switched converter with a fixed switching frequency. The FSQ-series is an integrated Pulse-Width Modulation (PWM) controller and SenseFET specifically designed for quasi-resonant operation and Alternating Valley Switching (AVS). The PWM controller includes an integrated fixed-frequency oscillator, Under-Voltage Lockout (UVLO), LeadingEdge Blanking (LEB), optimized gate driver, internal softstart, temperature-compensated precise current sources for a loop compensation, and self-protection circuitry. Compared with a discrete MOSFET and PWM controller solution, the FSQ-series can reduce total cost, component count, size, and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform that is well suited for cost-effective designs of quasi-resonant switching flyback converters. Low EMI through Variable Frequency Control and AVS (Alternating Valley Switching) High-Efficiency through Minimum Voltage Switching Narrow Frequency Variation Range over Wide Load and Input Voltage Variation Advanced Burst-Mode Operation for Low Standby Power Consumption Simple Scheme for Sync Voltage Detection Pulse-by-Pulse Current Limit Various Protection functions: Overload Protection (OLP), Over-Voltage Protection (OVP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) with Hysteresis, Output Short Protection (OSP) Under-Voltage Lockout (UVLO) with Hysteresis Internal Start-up Circuit Internal High-Voltage Sense FET (650V) Built-in Soft-Start (15ms) Applications Power Supply for LCD TV and Monitor, VCR, SVR, STB, and DVD & DVD Recorder Adapter Related Resourses Visit: http://www.fairchildsemi.com/apnotes/ for: AN-4134: Design Guidelines for Offline Forward Converters Using Fairchild Power Switch (FPS™) AN-4137: Design Guidelines for Offline Flyback Converters Using Fairchild Power Switch (FPS™) AN-4140: Transformer Design Consideration for Offline Flyback Converters Using Fairchild Power Switch (FPS™) AN-4141: Troubleshooting and Design Tips for Fairchild Power Switch (FPS™) Flyback Applications AN-4145: Electromagnetic Compatibility for Power Converters AN-4147: Design Guidelines for RCD Snubber of Flyback AN-4148: Audible Noise Reduction Techniques for Fairchild Power Switch Fairchild Power Switch(FPS™) Applications AN-4150: Design Guidelines for Flyback Converters Using FSQ-Series Fairchild Power Switch (FPS™) © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation October 2007 Maximum Output Power(1) Product Number PKG.(5) Operating Current RDS(ON) Temp. Limit Max. 230VAC±15%(2) 85-265VAC Adapter(3) Open Frame(4) Adapter(3) Open Frame(4) Replaces Devices FSQ0565R TO-220F-6L -25 to +85°C 3.0A 2.2Ω 70W 80W 41W 60W FSCM0565R FSDM0565RB FSQ0765R TO-220F-6L -25 to +85°C 3.5A 1.6Ω 80W 90W 48W 70W FSCM0765R FSDM0765RB Notes: 1. The junction temperature can limit the maximum output power. 2. 230VAC or 100/115VAC with doubler. 3. Typical continuous power in a non-ventilated enclosed adapter measured at 50°C ambient temperature. 4. Maximum practical continuous power in an open-frame design at 50°C ambient. 5. Pb-free package per JEDEC J-STD-020B. © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 2 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Ordering Information VO AC IN Vstr PWM Sync Drain GND VCC FB FSQ0765R Rev.00 Figure 1. Typical Flyback Application Internal Block Diagram Sync 5 AVS VCC Idelay FB 4 VCC Drain 6 3 1 OSC Vref 0.35/0.55 VBurst Vref Vstr VCC good 8V/12V IFB PWM 3R R SoftStart S Q LEB 250ns Gate driver R Q tON < tOSP after SS VOSP LPF AOCP VSD S TSD Q 2 VOCP (1.1V) GND R Q LPF VOVP VCC good FSQ0765R Rev.00 Figure 2. Internal Block Diagram © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 3 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Application Diagram 6. Vstr 5. Sync 4. FB 3. VCC 2. GND 1. Drain FSQ0765R Rev.00 Figure 3. Pin Configuration (Top View) Pin Definitions Pin # Name 1 Drain SenseFET drain. High-voltage power SenseFET drain connection. 2 GND Ground. This pin is the control ground and the SenseFET source. 3 VCC Power Supply. This pin is the positive supply input. This pin provides internal operating current for both start-up and steady-state operation. 4 FB Feedback. This pin is internally connected to the inverting input of the PWM comparator. The collector of an opto-coupler is typically tied to this pin. For stable operation, a capacitor should be placed between this pin and GND. If the voltage of this pin reaches 6V, the overload protection triggers, which shuts down the FPS. 5 Sync Sync. This pin is internally connected to the sync-detect comparator for quasi-resonant switching. In normal quasi-resonant operation, the threshold of the sync comparator is 1.2V/1.0V. Vstr Start-up. This pin is connected directly, or through a resistor, to the high-voltage DC link. At start-up, the internal high-voltage current source supplies internal bias and charges the external capacitor connected to the VCC pin. Once VCC reaches 12V, the internal current source is disabled. It is not recommended to connect Vstr and Drain together. 6 Description © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 4 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation 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 Parameter Min. Max. Unit Vstr Vstr Pin Voltage 500 V VDS Drain Pin Voltage 650 V VCC Supply Voltage VFB Feedback Voltage Range VSync IDM -0.3 Sync Pin Voltage -0.3 Drain Current Pulsed Continuous Drain V 11 V A FSQ0765R 15 A Current(6) TC = 25°C 2.8 TC = 100°C 1.7 TC = 25°C 3.8 TC = 100°C 2.4 A A FSQ0565R 190 mJ FSQ0765R 370 mJ 45 W Operating Junction Temperature Internally limited °C Operating Ambient Temperature -25 °C Storage Temperature -55 EAS Single Pulsed Avalanche Energy(7) PD Total Power Dissipation(Tc=25oC) TJ TA ESD 13 11 FSQ0765R TSTG V FSQ0565R FSQ0565R ID 20 +85 +150 °C Electrostatic Discharge Capability, Human Body Model 2.0 kV Electrostatic Discharge Capability, Charged Device Model 2.0 kV Notes: 6. Repetitive rating: Pulse width limited by maximum junction temperature. 7. L=14mH, starting TJ=25°C. Thermal Impedance TA = 25°C unless otherwise specified. Symbol θJA θJC Parameter Junction-to-Ambient Thermal Junction-to-Case Thermal Package Resistance(8) Resistance(9) TO-220F-6L Value Unit 50 °C/W 2.8 °C/W Notes: 8. Free standing with no heat-sink under natural convection. 9. Infinite cooling condition - refer to the SEMI G30-88. © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 5 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Absolute Maximum Ratings TA = 25°C unless otherwise specified. Symbol Parameter Condition Min. Typ. Max. Unit SENSEFET SECTION BVDSS Drain Source Breakdown Voltage VCC = 0V, ID = 100µA IDSS Zero-Gate-Voltage Drain Current VDS = 560V RDS(ON) Drain-Source On-State Resistance COSS Output Capacitance td(on) Turn-On Delay Time tr td(off) tf TJ = 25°C, ID = 0.5A 1.76 2.20 FSQ0765R TJ = 25°C, ID = 0.5A 1.4 1.6 FSQ0565R FSQ0565R FSQ0765R FSQ0565R FSQ0765R FSQ0565R Turn-Off Delay Time FSQ0765R FSQ0565R Fall Time V 250 FSQ0565R FSQ0765R Rise Time 650 FSQ0765R 78 VGS = 0V, VDS = 25V, f = 1MHz 22 ns 25 52 VDD = 350V, ID = 25mA ns 60 95 VDD = 350V, ID = 25mA ns 115 50 VDD = 350V, ID = 25mA Ω pF 100 VDD = 350V, ID = 25mA µA ns 65 CONTROL SECTION tON.MAX Maximum On Time TJ = 25°C 8.8 10.0 11.2 µs 13.2 15.0 16.8 µs tB Blanking Time TJ = 25°C, Vsync = 5V tW Detection Time Window TJ = 25°C, Vsync = 0V fS Initial Switching Frequency ΔfS tAVS Switching Frequency Variation(9) On Time 6.0 59.6 66.7 75.8 kHz -25°C < TJ < 85°C ±5 ±10 % at VIN = 240VDC, Lm = 360μH (AVS triggered when VAVS>spec & tAVS<spec.) 4.0 µs 1.2 V VAVS AVS Triggering Threshold(9) tSW Switching Time Variance by AVS(9) Sync = 500kHz sine input VFB = 1.2V, tON = 4.0µs 13.5 IFB Feedback Source Current VFB = 0V 700 Minimum Duty Cycle VFB = 0V DMIN VSTART VSTOP tS/S UVLO Threshold Voltage Internal Soft-Start Time Feedback Voltage µs 11 After turn-on 7 With free-running frequency 20.5 µs 1100 µA 0 % 12 13 V 8 9 900 17.5 V ms BURST-MODE SECTION TJ = 25°C, tPD = 200ns(8) VBURH VBURL Burst-Mode Voltages Hysteresis 0.45 0.55 0.65 0.25 0.35 0.45 200 V V mV Continued on the following page... © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 6 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Electrical Characteristics TA = 25°C unless otherwise specified. Symbol Parameter Condition Min. Typ. Max. Unit PROTECTION SECTION FSQ0565R TJ = 25°C, di/dt = 370mA/µs 2.64 3.00 3.36 FSQ0765R TJ = 25°C, di/dt = 460mA/µs 3.08 3.50 3.92 Shutdown Feedback Voltage VCC = 15V 5.5 6.0 6.5 V Shutdown Delay Current VFB = 5V 4 5 6 µA 1.4 µs ILIMIT Peak Current Limit VSD IDELAY tLEB Hys 1.2 ns Output Short Protection(9) Threshold Feedback Voltage TJ = 25°C OSP triggered when tON<tOSP , VFB>VOSP & lasts longer than t Feedback Blanking Time OSP_FB 1.8 2 2.5 3.0 Thermal Shutdown(9) Shutdown Temperature 125 140 155 tOSP_FB TSD 250 Threshold Time Leading-Edge Blanking tOSP VOSP Time(9) Hysteresis A 2.0 V 60 µs °C SYNC SECTION VSH1 VSL1 tsync VSH2 VSL2 VCLAMP VOVP tOVP Sync Threshold Voltage 1 VCC = 15V, VFB = 2V 1.0 1.2 1.4 0.8 1.0 1.2 Sync Delay Time(9)(10) 230 Sync Threshold Voltage 2 VCC = 15V, VFB = 2V Low Clamp Voltage ISYNC_MAX = 800µA ISYNC_MIN = 50µA Over-Voltage Threshold Voltage Protection Blanking Time(9) VCC = 15V, VFB = 2V V ns 4.3 4.7 5.1 4.0 4.4 4.8 0.0 0.4 0.8 V 7 8 9 V 1.0 1.7 2.4 µs 1 3 5 mA V TOTAL DEVICE SECTION IOP ISTART ICH VSTR Operating Supply Current (Control Part Only) VCC = 13V Start Current VCC = 10V (before VCC reaches VSTART) 350 450 550 µA Start-up Charging Current VCC = 0V, VSTR = mininmum 50V 0.65 0.85 1.00 mA Minimum VSTR Supply Voltage 26 V Notes: 8. Propagation delay in the control IC. 9. Guaranteed by design; not tested in production. 10. Includes gate turn-on time. © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 7 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Electrical Characteristics (Continued) Function Operation Method EMI Reduction FSDM0x65RE Constant Frequency PWM Frequency Modulation FSQ-Series Quasi-Resonant Operation Reduced EMI noise Reduced components to detect valley point Valley Switching Reduce EMI Noise Inherent Frequency Modulation Alternate Valley Switching CCM or AVS Based on Load Improves efficiency by introducing hybrid control and Input Condition Hybrid Control Burst-Mode Operation Burst-Mode Operation Advanced Burst-Mode Operation Strong Protections OLP, OVP OLP, OVP, AOCP, OSP TSD 145°C without Hysteresis 140°C with 60°C Hysteresis © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 FSQ-Series Advantages Improved efficiency by valley switching Improved standby power by AVS in burst-mode Improved reliability through precise AOCP Improved reliability through precise OSP Stable and reliable TSD operation Converter temperature range www.fairchildsemi.com 8 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Comparison Between FSDM0x65RNB and FSQ-Series 1.2 Normalized Normalized These characteristic graphs are normalized at TA= 25°C. 1.0 0.8 1.2 1.0 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 -25 0 25 50 75 100 0.0 -25 125 0 Temperature [°C] 1.2 1.0 0.8 0.4 0.2 0.2 75 100 0.0 -25 125 0 1.2 1.0 0.8 125 0.8 0.4 0.4 0.2 0.2 75 100 0.0 -25 125 0 25 50 75 100 125 Temperature [°C] Temperature [°C] Figure 8. Initial Switching Frequency (fS) vs. TA Figure 9. Maximum On Time (tON.MAX) vs. TA © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 100 1.0 0.6 50 75 1.2 0.6 25 50 Figure 7. Start-up Charging Current (ICH) vs. TA Normalized Normalized Figure 6. UVLO Stop Threshold Voltage (VSTOP) vs. TA 0 25 Temperature [°C] Temperature [°C] 0.0 -25 125 0.8 0.4 50 100 1.0 0.6 25 75 1.2 0.6 0 50 Figure 5. UVLO Start Threshold Voltage (VSTART) vs. TA Normalized Normalized Figure 4. Operating Supply Current (IOP) vs. TA 0.0 -25 25 Temperature [°C] www.fairchildsemi.com 9 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Typical Performance Characteristics 1.2 Normalized Normalized These characteristic graphs are normalized at TA= 25°C. 1.0 0.8 1.2 1.0 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 -25 0 25 50 75 100 0.0 -25 125 0 1.2 1.0 0.8 0.4 0.2 0.2 75 100 0.0 -25 125 0 1.2 1.0 0.8 125 0.8 0.4 0.4 0.2 0.2 75 100 0.0 -25 125 Temperature [°C] 0 25 50 75 100 125 Temperature [°C] Figure 14. Burst-Mode Low Threshold Voltage (Vburl) vs. TA Figure 15. Peak Current Limit (ILIM) vs. TA © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 100 1.0 0.6 50 75 1.2 0.6 25 50 Figure 13. Burst-Mode High Threshold Voltage (Vburh) vs. TA Normalized Normalized Figure 12. Shutdown Delay Current (IDELAY) vs. TA 0 25 Temperature [°C] Temperature [°C] 0.0 -25 125 0.8 0.4 50 100 1.0 0.6 25 75 1.2 0.6 0 50 Figure 11. Feedback Source Current (IFB) vs. TA Normalized Normalized Figure 10. Blanking Time (tB) vs. TA 0.0 -25 25 Temperature [°C] Temperature [°C] www.fairchildsemi.com 10 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Typical Performance Characteristics (Continued) 1.2 Normalized Normalized These characteristic graphs are normalized at TA= 25°C. 1.0 0.8 1.2 1.0 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 -25 0 25 50 75 100 0.0 -25 125 0 1.2 1.0 0.8 0.4 0.2 0.2 75 100 0.0 -25 125 0 1.2 1.0 0.8 125 0.8 0.4 0.4 0.2 0.2 75 100 0.0 -25 125 Temperature [°C] 0 25 50 75 100 125 Temperature [°C] Figure 20. Sync High Threshold Voltage 2 (VSH2) vs. TA Figure 21. Sync Low Threshold Voltage 2 (VSL2) vs. TA © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 100 1.0 0.6 50 75 1.2 0.6 25 50 Figure 19. Over-Voltage Protection (VOV) vs. TA Normalized Normalized Figure 18. Shutdown Feedback Voltage (VSD) vs. TA 0 25 Temperature [°C] Temperature [°C] 0.0 -25 125 0.8 0.4 50 100 1.0 0.6 25 75 1.2 0.6 0 50 Figure 17. Sync Low Threshold Voltage 1 (VSL1) vs. TA Normalized Normalized Figure 16. Sync High Threshold Voltage 1 (VSH1) vs. TA 0.0 -25 25 Temperature [°C] Temperature [°C] www.fairchildsemi.com 11 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Typical Performance Characteristics (Continued) 2.2 Leading-Edge Blanking (LEB): At the instant the internal SenseFET is turned on, a high-current spike usually occurs through the SenseFET, caused by primary-side capacitance and secondary-side rectifier reverse recovery. Excessive voltage across the Rsense resistor would lead to incorrect feedback operation in the current-mode PWM control. To counter this effect, the FPS employs a leading-edge blanking (LEB) circuit. This circuit inhibits the PWM comparator for a short time (tLEB) after the SenseFET is turned on. 1. Start-up: At start-up, an internal high-voltage current source supplies the internal bias and charges the external capacitor (Ca) connected to the VCC pin, as illustrated in Figure 22. When VCC reaches 12V, the FPS™ begins switching and the internal high-voltage current source is disabled. The FPS continues its normal switching operation and the power is supplied from the auxiliary transformer winding unless VCC goes below the stop voltage of 8V. Vref VCC VDC Idelay VFB VO 4 FOD817A Ca IFB SenseFET OSC D1 CB D2 3R + VFB* 3 VCC 6 Vstr KA431 - ICH 8V/12V VCC good FSQ0765R Rev.00 Gate driver R OLP VSD Rsense FSQ0765R Rev. 00 Vref Figure 23. Pulse-Width-Modulation (PWM) Circuit Internal Bias 3. Synchronization: The FSQ-series employs a quasiresonant switching technique to minimize the switching noise and loss. The basic waveforms of the quasiresonant converter are shown in Figure 24. To minimize the MOSFET's switching loss, the MOSFET should be turned on when the drain voltage reaches its minimum value, which is indirectly detected by monitoring the VCC winding voltage, as shown in Figure 24. Figure 22. Start-up Circuit 2. Feedback Control: FPS employs current-mode control, as shown in Figure 23. An opto-coupler (such as the FOD817A) and shunt regulator (such as the KA431) are typically used to implement the feedback network. Comparing the feedback voltage with the voltage across the Rsense resistor makes it possible to control the switching duty cycle. When the reference pin voltage of the shunt regulator exceeds the internal reference voltage of 2.5V, the opto-coupler LED current increases, pulling down the feedback voltage and reducing the duty cycle. This typically happens when the input voltage is increased or the output load is decreased. Vds VRO VRO VDC tF Vsync Vovp (8V) 2.1 Pulse-by-Pulse Current Limit: Because currentmode control is employed, the peak current through the SenseFET is limited by the inverting input of PWM comparator (VFB*), as shown in Figure 23. Assuming that the 0.9mA current source flows only through the internal resistor (3R + R = 2.8k), the cathode voltage of diode D2 is about 2.5V. Since D1 is blocked when the feedback voltage (VFB) exceeds 2.5V, the maximum voltage of the cathode of D2 is clamped at this voltage, clamping VFB*. Therefore, the peak value of the current through the SenseFET is limited. 1.2V 1.0V 230ns Delay MOSFET Gate ON FSQ0765R Rev.00 Figure 24. Quasi-Resonant Switching Waveforms © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 ON www.fairchildsemi.com 12 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Functional Description IDS IDS VDS ingnore 4.4V Vsync 1.2V 1.0V internal delay tX tB=15μs tX tB=15μs FSQ0765R Rev. 00 Figure 27. After Vsync Finds First Valley IDS 4. Protection Circuits: The FSQ-series has several self-protective functions, such as Overload Protection (OLP), Abnormal Over-Current Protection (AOCP), Over-Voltage Protection (OVP), and Thermal Shutdown (TSD). All the protections are implemented as autorestart mode. Once the fault condition is detected, switching is terminated and the SenseFET remains off. This causes VCC to fall. When VCC falls down to the Under-Voltage Lockout (UVLO) stop voltage of 8V, the protection is reset and the start-up circuit charges the VCC capacitor. When the VCC reaches the start voltage of 12V, normal operation resumes. If the fault condition is not removed, the SenseFET remains off and VCC drops to stop voltage again. In this manner, the auto-restart can alternately enable and disable the switching of the power SenseFET until the fault condition is eliminated. Because these protection circuits are fully integrated into the IC without external components, the reliability is improved without increasing cost. IDS VDS 4.4V Vsync 1.2V 1.0V internal delay FSQ0765R Rev. 00 Figure 25. Vsync > 4.4V at tX tX tB=15μs IDS VDS IDS Power on Fault occurs Fault removed VDS VCC 4.4V Vsync internal delay 12V 1.2V 1.0V 8V FSQ0765R Rev. 00 FSQ0765R Rev. 00 Figure 26. Vsync < 4.4V at tX Fault situation Normal operation t Figure 28. Auto Restart Protection Waveforms © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 Normal operation www.fairchildsemi.com 13 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation The switching frequency is the combination of blank time (tB) and detection time window (tW). In case of a heavy load, the sync voltage remains flat after tB and waits for valley detection during tW. This leads to a low switching frequency not suitable for heavy loads. To correct this drawback, additional timing is used. The timing conditions are described in Figures 25, 26, and 27. When the Vsync remains flat higher than 4.4V at the end of tB that is tX, the next switching cycle starts after internal delay time from tX. In the second case, the next switching occurs on the valley when the Vsync goes below 4.4V within tB. Once Vsync detects the first valley within tB, the other switching cycle follows classical QRC operation. OSC PWM LEB 250ns S Q R Q Gate driver R + AOCP - VFB 3R FSQ0765R Rev.00 R sense 2 GND VOCP Figure 30. Abnormal Over-Current Protection 4.3 Output-Short Protection (OSP): If the output is shorted, steep current with extremely high di/dt can flow through the SenseFET during the LEB time. Such a steep current brings high voltage stress on drain of SenseFET when turned off. To protect the device from such an abnormal condition, OSP is included in the FSQseries. It is comprised of detecting VFB and SenseFET turn-on time. When the VFB is higher than 2V and the SenseFET turn-on time is lower than 1.2µs, the FPS recognizes this condition as an abnormal error and shuts down PWM switching until VCC reaches Vstart again. An abnormal condition output short is shown in Figure 31. MOSFET Drain Current FSQ0765R Rev.00 Overload protection 6.0V Rectifier Diode Current Turn-off delay ILIM VFB 0 2.5V Minimum turn-on time Vo D 1.2us output short occurs t12= CFB*(6.0-2.5)/Idelay 0 t1 t2 t Io FSQ0765R Rev. 00 Figure 29. Overload Protection 0 Figure 31. Output Short Waveforms 4.2 Abnormal Over-Current Protection (AOCP): When the secondary rectifier diodes or the transformer pins are shorted, a steep current with extremely high di/dt can flow through the SenseFET during the LEB time. Even though the FSQ-series has overload protection, it is not enough to protect the FSQ-series in that abnormal case, since severe current stress is imposed on the SenseFET until OLP triggers. The FSQ-series has an internal AOCP circuit shown in Figure 30. When the gate turn-on signal is applied to the power SenseFET, the AOCP block is enabled and monitors the current through the sensing resistor. The voltage across the resistor is compared with a preset AOCP level. If the sensing resistor voltage is greater than the AOCP level, the set signal is applied to the latch, resulting in the shutdown of the SMPS. 4.4 Over-Voltage Protection (OVP): If the secondaryside feedback circuit malfunctions or a solder defect causes an opening in the feedback path, the current through the opto-coupler transistor becomes almost zero. VFB climbs up in a similar manner to the overload situation, forcing the preset maximum current to be supplied to the SMPS until the overload protection triggers. Because more energy than required is provided to the output, the output voltage may exceed the rated voltage before the overload protection triggers, resulting in the breakdown of the devices in the secondary side. To prevent this situation, an OVP circuit is employed. In general, the peak voltage of the sync signal is proportional to the output voltage and the FSQ-series © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 14 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation 4.1 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 SMPS. However, even when the SMPS is in the normal operation, the overload protection circuit can be triggered during the load transition. To avoid this undesired operation, the overload protection circuit is designed to trigger only after a specified time to determine whether it is a transient situation or a true overload situation. Because of the pulse-by-pulse current limit capability, the maximum peak current through the SenseFET is limited, and therefore the maximum input power is restricted with a given input voltage. If the output consumes more than this maximum power, the output voltage (VO) decreases below the set voltage. This reduces the current through the optocoupler LED, which also reduces the opto-coupler transistor current, thus increasing the feedback voltage (VFB). If VFB exceeds 2.5V, D1 is blocked and the 5µA current source starts to charge CB slowly up to VCC. In this condition, VFB continues increasing until it reaches 6V, when the switching operation is terminated, as shown in Figure 29. The delay time for shutdown is the time required to charge CFB from 2.5V to 6V with 5µA. A 20 ~ 50ms delay time is typical for most applications. VVcc_coil &VCC FSQ0765R Rev.00 Absolue max VCC (20V) VCC VVcc_coil VO VOset VDC Npri VFB NVcc 0.55V Improper OVP triggering Vsync 0.35V VOVP (8V) tOVP IDS VSH2 (4.8V) tOVP VCLAMP VDS Figure 32. OVP Triggering 4.5 Thermal Shutdown with Hysteresis (TSD): The SenseFET and the control IC are built in one package. This makes it easy for the control IC to detect the abnormally high temperature of the SenseFET. If the temperature exceeds approximately 140°C, the thermal shutdown triggers IC shutdown. The IC recovers its operation when the junction temperature decreases 60°C from TSD temperature and VCC reaches start-up voltage (Vstart). time FSQ0765R Rev.00 t2 t3 Switching disabled t4 Figure 33. Waveforms of Burst Operation 7. Switching Frequency Limit: To minimize switching loss and Electromagnetic Interference (EMI), the MOSFET turns on when the drain voltage reaches its minimum value in quasi-resonant operation. However, this causes switching frequency to increases at light load conditions. As the load decreases or input voltage increases, the peak drain current diminishes and the switching frequency increases. This results in severe switching losses at light-load condition, as well as intermittent switching and audible noise. These problems create limitations for the quasi-resonant converter topology in a wide range of applications. 5. Soft-Start: The FPS has an internal soft-start circuit that increases PWM comparator inverting input voltage with the SenseFET current slowly after it starts up. The typical soft-start time is 15ms. The pulse width to the power switching device is progressively increased to establish the correct working conditions for transformers, inductors, and capacitors. The voltage on the output capacitors is progressively increased with the intention of smoothly establishing the required output voltage. This mode helps prevent transformer saturation and reduces stress on the secondary diode during start-up. To overcome these problems, FSQ-series employs a frequency-limit function, as shown in Figures 34 and 35. Once the SenseFET is turned on, the next turn-on is prohibited during the blanking time (tB). After the blanking time, the controller finds the valley within the detection time window (tW) and turns on the MOSFET, as shown in Figures 34 and Figure 35 (Cases A, B, and C). © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 t1 Switching disabled www.fairchildsemi.com 15 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation 6. Burst Operation: To minimize power dissipation in standby mode, the FPS enters burst-mode operation. As the load decreases, the feedback voltage decreases. As shown in Figure 33, the device automatically enters burst-mode when the feedback voltage drops below VBURL (350mV). At this point, switching stops and the output voltages start to drop at a rate dependent on standby current load. This causes the feedback voltage to rise. Once it passes VBURH (550mV), switching resumes. The feedback voltage then falls and the process repeats. Burst-mode operation alternately enables and disables switching of the power SenseFET, thereby reducing switching loss in standby mode. uses a sync signal instead of directly monitoring the output voltage. If the sync signal exceeds 8V, an OVP is triggered, shutting down the SMPS. To avoid undesired triggering of OVP during normal operation, there are two points considered, as depicted in Figure 32. The peak voltage of the sync signal should be designed below 6V and the spike of the SYNC pin must be as low as possible to avoid getting longer than tOVP by decreasing the leakage inductance shown at VCC winding coil. Internally, quasi-resonant operation is divided into two categories; one is first valley switching and the other is second-valley switching after blanking time. In AVS, two successive occurrences of first-valley switching and the other two successive occurrences of second-valley switching is alternatively selected to maximize frequency modulation. As depicted in Figure 35, the switching frequency hops when the input voltage is high. The internal timing diagram of AVS is described in Figure 36. Figure 35. Switching Frequency Range Figure 34. QRC Operation with Limited Frequency Figure 36. Alternating Valley Switching (AVS) © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 16 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation 8. AVS (Alternating Valley Switching): Due to the quasi-resonant operation with limited frequency, the switching frequency varies depending on input voltage, load transition, and so on. At high input voltage, the switching on time is relatively small compared to low input voltage. The input voltage variance is small and the switching frequency modulation width becomes small. To improve the EMI performance, AVS is enabled when input voltage is high and the switching on time is small. If no valley is found during tW, the internal SenseFET is forced to turn on at the end of tW (Case D). Therefore, the devices have a minimum switching frequency of 48kHz and a maximum switching frequency of 67kHz. Due to the combined scheme, FPS shows better noise immunity than conventional PWM controller and MOSFET discrete solution. Further more, internal drain current sense eliminates the possibility of noise generation caused by a sensing resistor. There are some recommendations for PCB layout to enhance noise immunity and suppress natural noise inevitable in powerhandling components. There are typically two grounds in the conventional SMPS: power ground and signal ground. The power ground is the ground for primary input voltage and power, while the signal ground is ground for PWM controller. In FPS, those two grounds share the same pin, GND. Normally the separate grounds do not share the same trace and meet only at one point, the GND pin. More, wider patterns for both grounds are good for large currents by decreasing resistance. Capacitors at the VCC and FB pins should be as close as possible to the corresponding pins to avoid noise from the switching device. Sometimes Mylar® or ceramic capacitors with electrolytic for VCC is better for smooth operation. The ground of these capacitors needs to connect to the signal ground (not power ground). Figure 37. Recommended PCB Layout The cathode of the snubber diode should be close to the drain pin to minimize stray inductance. The Y-capacitor between primary and secondary should be directly connected to the power ground of DC link to maximize surge immunity. Because the voltage range of feedback and sync line is small, it is affected by the noise of the drain pin. Those traces should not draw across or close to the drain line. When the heat sink is connected to the ground, it should be connected to the power ground. If possible, avoid using jumper wires for power ground and drain. Mylar® is a registered trademark of DuPont Teijin Films. © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 17 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation PCB Layout Guide Application FPS™ Device Input Voltage Range Rated Output Power Output Voltage (Maximum Current) LCD Monitor Power Supply FSQ0565R 85-265VAC 46W 5.1V (2.0A) 12V (3.0A) Features Average efficiency of 25%, 50%, 75%, and 100% load conditions is higher than 80% at universal input Low standby mode power consumption (<1W at 230VAC input and 0.5W load) Reduce EMI noise through valley switching operation Enhanced system reliability through various protection functions Internal soft-start (15ms) Key Design Notes The delay time for overload protection is designed to be about 23ms with C105 of 33nF. If faster/slower triggering of OLP is required, C105 can be changed to a smaller/larger value (e.g. 100nF for 70ms). The input voltage of VSync must be between 4.7V and 8V just after MOSFET turn-off to guarantee hybrid control and to avoid OVP triggering during normal operation. The SMD-type 100nF capacitor must be placed as close as possible to VCC pin to avoid malfunction by abrupt pul- sating noises and to improve surge immunity. 1. Schematic FSQ0765R Rev.00 D201 T1 MBRF10H100 EER3016 BD101 2KBP06M3N257 2 C104 4.7nF 630V R103 33kΩ 1W C103 100μF 400V D101 1N 4007 C202 1000μF 25V C201 1000μF 25V 8 2 R104 20Ω 0.5W 12V, 3A 10 1 R102 68kΩ L201 5μH 3 FSQ0565R 1 6 3 C105 33nF 100V C102 150nF 275VAC Drain 1 R105 C106 C107 100Ω 100nF 47μF Vcc 0.5W SMD 50V 4 3 Vfb GND D102 UF 4004 R107 2 18kΩ 5 4 Vstr D202 MBRF1060 Sync 4 LF101 34mH R108 12kΩ 5V, 2A 7 C204 1000μF 10V C203 1000μF 10V 6 5 ZD101 1N4745A L202 5μH C301 4.7nF 1kV R201 1kΩ R101 2MΩ 1W R202 1.2kΩ Optional components RT1 5D-9 C101 150nF 275VAC IC301 FOD817A F1 FUSE 250V 2A IC201 KA431 R204 4kΩ R203 1.2kΩ C205 47nF R205 4kΩ Figure 38. Demo Circuit of FSQ0565R © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 18 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Typical Application Circuit FSQ0765R Rev.00 EER3016 1 TAPE 4T FSQ0765R Rev.00 1 10 N /2 12V Lp/2 L12V/2 Np/2 Np/2 Na 2 3 L5V 7 (TIW 0.5φ, 2parallel) N5V 8 TAPE 2T 5 7 TAPE 2T 6 6 TAPE 2T 10 (TIW 0.5φ, 2parallel) 10 9 9 TAPE 2T 2 Lp/2 TAPE 1T 3 (0.4φ) 5 8 4 L12V/2 7 9 LVcc(0.2φ) 8 4 TAPE 2T 9 (TIW 0.5φ, 2parallel) 9 N /2 12V TAPE 1T 2 (0.4φ) 6 Bottom of bobbin Figure 39. Transformer Schematic Diagram of FSQ0565R 3. Winding Specification Position Top No Pin (s→f) Wire Turns Winding Method Insulation: Polyester Tape t = 0.025mm, 4 Layers Np/2 0.4φ × 1 2→1 20 2-Layer Solenoid Winding 4 Center Solenoid Winding 10 Center Solenoid Winding 4 Center Solenoid Winding 5 Center Solenoid Winding 32 2-Layer Solenoid Winding Insulation: Polyester Tape t = 0.025mm, 2 Layers N12V/2 0.5φ × 2(TIW) 9→8 Insulation: Polyester Tape t = 0.025mm, 2 Layers Na 0.15φ × 1 4→5 Insulation: Polyester Tape t = 0.025mm, 2 Layers N5V 0.5φ × 2(TIW) 7→6 Insulation: Polyester Tape t = 0.025mm, 2 Layers N12V/2 0.5φ × 2(TIW) 10 → 9 Insulation: Polyester Tape t = 0.025mm, 2 Layers Bottom Np/2 0.4φ × 1 3→2 4. Electrical Characteristics Pin Specification Remarks Inductance 1-3 360µH ± 10% 100kHz, 1V Leakage 1-3 15µH Maximum Short all other pins 5. Core & Bobbin Core: EER3016 (Ae=109.7mm2) Bobbin: EER3016 © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 19 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation 2. Transformer Part Value Note Resistor Part Value Note C205 47nF/50V Ceramic Capacitor C301 4.7nF/1kV Ceramic Capacitor R101 2MΩ 1W R102 68kΩ 1/2W R103 33kΩ 1W L201 5µH 5A Rating R104 20Ω 1W L202 5µH 5A Rating R105 100Ω optional, 1/4W R107 18kΩ 1/4W D101 IN4007 1A, 1000V General-Purpose Rectifier R108 12kΩ 1/4W D102 UF4004 1A, 400V Ultrafast Rectifier R201 1kΩ 1/4W ZD101 1N4745A 1W 16V Zener Diode (optional) R202 1.2kΩ 1/4W D201 MBRF10H100 10A,100V Schottky Rectifier R203 1.2kΩ 1/4W D202 MBRF1060 R204 5.2kΩ 1/4W R205 4.7kΩ 1/4W Capacitor C101 150nF/275VAC Box Capacitor C102 150nF/275VAC Box Capacitor C103 100µF/400V Electrolytic Capacitor C104 4.7nF/630V Film Capacitor C105 33nF/50V Ceramic Capacitor C106 100nF/50V SMD (1206) C107 47µF/50V Electrolytic Capacitor C201 1000µF/25V Low ESR Electrolytic Capacitor C202 1000µF/25V Low ESR Electrolytic Capacitor C203 1000µF/10V Low ESR Electrolytic Capacitor C204 1000µF/10V Low ESR Electrolytic Capacitor Inductor Diode IC101 FSQ0565R FPS™ IC201 KA431 (TL431) Voltage Reference IC202 FOD817A Opto-Coupler Fuse Fuse 2A/250V NTC RT101 5D-9 Bridge Diode BD101 2KBP06M2N257 Bridge Diode Line Filter LF101 34mH Transformer T1 © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 10A,60V Schottky Rectifier IC EER3016 Ae=109.7mm2 www.fairchildsemi.com 20 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation 6. Demo Board Part List FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation Package Dimensions TO-220F-6L (Forming) MKT-TO220A06revB Figure 40. 6-Lead, TO-220 Package © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 21 ® ACEx Build it Now¥ CorePLUS¥ CROSSVOLT¥ CTL™ Current Transfer Logic™ ® EcoSPARK ® ® Fairchild ® Fairchild Semiconductor FACT Quiet Series™ ® FACT ® FAST FastvCore¥ FPS¥ ® FRFET SM Global Power Resource ® Power247 ® POWEREDGE Power-SPM¥ ® PowerTrench Programmable Active Droop¥ ® QFET QS¥ QT Optoelectronics¥ Quiet Series¥ RapidConfigure¥ SMART START¥ ® SPM STEALTH™ SuperFET¥ SuperSOT¥-3 SuperSOT¥-6 Green FPS¥ Green FPS¥ e-Series¥ GTO¥ i-Lo¥ IntelliMAX¥ ISOPLANAR¥ MegaBuck™ MICROCOUPLER¥ MicroFET¥ MicroPak¥ MillerDrive™ Motion-SPM™ ® OPTOLOGIC ® OPTOPLANAR ® PDP-SPM™ ® Power220 SuperSOT¥-8 SyncFET™ ® The Power Franchise TinyBoost¥ TinyBuck¥ ® TinyLogic TINYOPTO¥ TinyPower¥ TinyPWM¥ TinyWire¥ PSerDes¥ ® UHC UniFET¥ VCX¥ DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION, OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. THESE SPECIFICATIONS DO NOT EXPAND THE TERMS OF FAIRCHILD’S WORLDWIDE TERMS AND CONDITIONS, SPECIFICALLY THE WARRANTY THEREIN, WHICH COVERS THESE PRODUCTS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support, device, or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. PRODUCT STATUS DEFINITIONS Definition of Terms Datasheet Identification Product Status Advance Information Formative or In Design This datasheet contains the design specifications for product development. Specifications may change in any manner without notice. Definition Preliminary First Production This datasheet contains preliminary data; supplementary data will be published at a later date. Fairchild Semiconductor reserves the right to make changes at any time without notice to improve design. No Identification Needed Full Production This datasheet contains final specifications. Fairchild Semiconductor reserves the right to make changes at any time without notice to improve design. Obsolete Not In Production This datasheet contains specifications on a product that has been discontinued by Fairchild Semiconductor. The datasheet is printed for reference information only. Rev. I31 © 2007 Fairchild Semiconductor Corporation FSQ0565R, FSQ0765R Rev. 1.0.0 www.fairchildsemi.com 22 FSQ0565R, FSQ0765R — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation TRADEMARKS The following are registered and unregistered trademarks and service marks Fairchild Semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks.