300W开关电源

©2005 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev.1.1.0FPSTM is a trademark of Fairchild Semiconductor Corporation. Features • Optimized for Quasi-Resonant Converter (QRC) • Advanced Burst-Mode Operation for under 1W Standby Power Consumption • Pulse-by-Pulse Current Limit • Over Load Protection (OLP) - Auto Restart • Over Voltage Protection (OVP) - Auto Restart • Abnormal Over Current Protection (AOCP) - Latch • Internal Thermal Shutdown (TSD) - Latch • Under Voltage Lock Out (UVLO) with Hysteresis • Low Startup Current (typical : 25uA) • Internal High Voltage SenseFET • Built-in Soft Start (20ms) • Extended Quasi-Resonant Switching Applications • CTV • Audio Amplifier Related Application Notes • AN4146 - Design Guidelines for Quasi-Resonant Converters Using FSCQ-Series Fairchild Power Switch. • AN4140 - Transformer Design Consideration for Off-Line Flyback Converters Using Fairchild Power Switch. Description In general, a Quasi-Resonant Converter (QRC) shows lower EMI and higher power conversion efficiency compared to conventional hard-switched converter with a fixed switching frequency. Therefore, a QRC is well suited for noise- sensitive applications, such as color TV and audio. Each product in the FSCQ-Series contains an integrated Pulse Width Modulation (PWM) controller and a SenseFET, and is specifically designed for quasi-resonant off-line Switch Mode Power Supplies (SMPS) with minimal external components. The PWM controller includes an integrated fixed frequency oscillator, under voltage lockout, leading edge blanking (LEB), optimized gate driver, internal soft start, temperature-compensated precise current sources for a loop compensation, and self protection circuitry. Compared with a discrete MOSFET and PWM controller solution, the FSCQ- Series can reduce total cost, component count, size, and weight, while simultaneously increasing efficiency, productivity, and system reliability. These devices provide a basic platform that is well suited for cost-effective designs of quasi-resonant switching flyback converters. Table 1. Maximum Output Power Notes: 1. Maximum practical continuous power in an open frame design at 50°C ambient. 2. 230 VAC or 100/115 VAC with doubler. 3. The junction temperature can limit the maximum output power. Typical Circuit Figure 1. Typical Flyback Application OUTPUT POWER TABLE(3) PRODUCT 230VAC ±15%(2) 85-265VAC Open Frame(1) Open Frame(1) FSCQ0565RT 70W 60 W FSCQ0765RT 100 W 85 W FSCQ0965RT 130 W 110 W FSCQ1265RT 170 W 140 W FSCQ1465RT 190 W 160 W FSCQ1565RT 210 W 170 W FSCQ1565RP 250 W 210 W Vcc GND Drain Sync Vo PWM VFB AC IN FSCQ-Series FSCQ-Series FSCQ0565RT / FSCQ0765RT / FSCQ0965RT / FSCQ1265RT FSCQ1465RT / FSCQ1565RT / FSCQ1565RP Green Mode Fairchild Power Switch (FPSTM) Administrator 单位部门，完整姓名，日期 Administrator 单位部门，完整姓名，日期 FSCQ-SERIES 2 Internal Block Diagram Figure 2. Functional Block Diagram of FSCQ-Series 9V/15V 3 1 2 4 Auxiliary Vref Main Bias S Q Q R OSC Vcc Vref Idelay IFB VSD TSD Vovp Sync Vocp S Q Q R R 2.5R Vcc good (Vcc = 9V) Vcc Drain VFB GND AOCP Gate Driver Vcc good LEB 600ns PWM Soft Start Internal Bias Normal Operation VBurst Vref IB Vref IBFB Burst Mode Controller Normal Operation Burst Switching 5 Sync Threshold Quasi-Resonant (QR) Switching Controller + - + - S Q Q R Power Off Reset (Vcc = 6V) 4.6V/2.6V : Normal QR 3.0V/1.8V : Extended QR fs FSCQ-SERIES 3 Pin Definitions Pin Configuration Figure 3. Pin Configuration (Top View) Pin Number Pin Name Pin Function Description 1 Drain High voltage power SenseFET drain connection. 2 GND This pin is the control ground and the SenseFET source. 3 Vcc This pin is the positive supply input. This pin provides internal operatingcurrent for both start-up and steady-state operation. 4 Vfb 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 7.5V, the over load protection triggers, which results in the FPS shutting down. 5 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 4.6V/2.6V. Whereas, the sync threshold is changed to 3.0V/1.8V in an extended quasi-resonant operation. 5.Sync 4.Vfb 3.Vcc 2.GND 1.Drain TO-220F-5L 5.Sync 4.Vfb 3.Vcc 2.GND 1.Drain TO-3PF-7L FSCQ-SERIES 4 Absolute Maximum Ratings (Ta=25°C, unless otherwise specified) Parameter Symbol Value Unit Drain Pin Voltage VDS 650 V Supply Voltage VCC 20 V Analog Input Voltage Range Vsync -0.3 to 13V V VFB -0.3 to VCC V Drain Current Pulsed (1) IDM FSCQ0565RT 11.2 A FSCQ0765RT 15.2 FSCQ0965RT 16.4 FSCQ1265RT 21.2 FSCQ1465RT 22 FSCQ1565RT 26.4 FSCQ1565RP 33.2 Continuous Drain Current(Tc=25°C) (Tc : Case Back Surface Temperature) ID FSCQ0565RT 2.8 A (rms) FSCQ0765RT 3.8 FSCQ0965RT 4.1 FSCQ1265RT 5.3 FSCQ1465RT 5.5 FSCQ1565RT 6.6 FSCQ1565RP 8.3 Continuous Drain Current * (TDL=25°C) (TDL :Drain Lead Temperature) ID* FSCQ0565RT 5 A (rms) FSCQ0765RT 7 FSCQ0965RT 7.6 FSCQ1265RT 11 FSCQ1465RT 12 FSCQ1565RT 13.3 FSCQ1565RP 15 Continuous Drain Current (TC=100°C) ID FSCQ0565RT 1.7 A (rms) FSCQ0765RT 2.4 FSCQ0965RT 2.6 FSCQ1265RT 3.4 FSCQ1465RT 3.5 FSCQ1565RT 4.4 FSCQ1565RP 5.5 Single-Pulsed Avalanche Energy (2) EAS FSCQ0565RT 400 mJ FSCQ0765RT 570 FSCQ0965RT 630 FSCQ1265RT 950 FSCQ1465RT 1000 FSCQ1565RT 1050 FSCQ1565RP 1050 FSCQ-SERIES 5 Notes: 1. Repetitive rating: Pulse width limited by maximum junction temperature 2. L = 15mH, starting Tj = 25°C, These parameters, although guaranteed at the design, are not tested in mass production. Thermal Impedance (Ta=25°C unless otherwise specified) Total Power Dissipation (Tc=25°C with Infinite Heat Sink) PD FSCQ0565RT 38 W FSCQ0765RT 45 FSCQ0965RT 49 FSCQ1265RT 50 FSCQ1465RT 60 FSCQ1565RT 75 FSCQ1565RP 98 Operating Junction Temperature TJ +150 °C Operating Ambient Temperature TA -25 to +85 °C Storage Temperature Range TSTG -55 to +150 °C ESD Capability, HBM Model (All pins except Vfb) - 2.0 (GND-Vfb=1.7kV) kV ESD Capability, Machine Model (All pins except Vfb) - 300 (GND-Vfb=170V) V Parameter Symbol Value Unit Junction to Case Thermal Impedance θJC FSCQ0565RT 3.29 °C/W FSCQ0765RT 2.60 FSCQ0965RT 2.55 FSCQ1265RT 2.50 FSCQ1465RT 2.10 FSCQ1565RT 2.00 FSCQ1565RP 1.28 Administrator 单位部门，完整姓名，日期 FSCQ-SERIES 6 Electrical Characteristics (SenseFET Part) (Ta=25°C unless otherwise specified) Parameter Symbol Condition Min. Typ. Max. Unit Drain-Source Breakdown Voltage BVDSS VGS = 0V, ID = 250μA 650 - - V Zero Gate Voltage Drain Current IDSS VDS = 650V,VGS = 0V - - 250 μA Drain-Source ON-State Resistance RDS(ON) FSCQ0565RT VGS = 10V, ID = 1A - 1.76 2.2 Ω FSCQ0765RT VGS = 10V, ID = 1A - 1.4 1.6 Ω FSCQ0965RT VGS = 10V, ID = 1A - 1.0 1.2 Ω FSCQ1265RT VGS = 10V, ID = 1A - 0.75 0.9 Ω FSCQ1465RT VGS = 10V, ID = 1A - 0.7 0.8 Ω FSCQ1565RT VGS = 10V, ID = 1A - 0.53 0.7 Ω FSCQ1565RP VGS = 10V, ID = 1A - 0.53 0.7 Ω Input Capacitance CISS FSCQ0565RT VGS = 0V, VDS = 25V, f = 1MHz - 1080 - pF FSCQ0765RT - 1415 - FSCQ0965RT - 1750 - FSCQ1265RT - 2400 - FSCQ1465RT - 2400 - FSCQ1565RT - 3050 - FSCQ1565RP - 3050 - Output Capacitance COSS FSCQ0565RT VGS = 0V, VDS = 25V, f = 1MHz - 90 - pF FSCQ0765RT - 100 - FSCQ0965RT - 130 - FSCQ1265RT - 175 - FSCQ1465RT - 185 - FSCQ1565RT - 220 - FSCQ1565RP - 220 - FSCQ-SERIES 7 Electrical Characteristics (Continued) (Ta=25°C unless otherwise specified) Note: 1. These parameters, although guaranteed, are tested only in EDS (wafer test) process. 2. These parameters, although guaranteed at the design, are not tested in mass production. Parameter Symbol Condition Min. Typ. Max. Unit CONTROL SECTION Switching Frequency FOSC VFB = 5V, VCC = 18V 18 20 22 kHz Switching Frequency Variation(1) ΔFOSC -25°C ≤ Ta ≤ 85°C 0 ±5 ±10 % Feedback Source Current IFB VFB = 0.8V, VCC = 18V 0.5 0.65 0.8 mA Maximum Duty Cycle DMAX VFB = 5V, VCC = 18V 92 95 98 % Minimum Duty Cycle DMIN VFB = 0V, VCC = 18V - 0 - % UVLO Threshold Voltage VSTART VFB=1V 14 15 16 V VSTOP VFB=1V 8 9 10 V Soft Start Time (1) TSS - 18 20 22 ms BURST MODE SECTION Burst Mode Enable Feedback Voltage VBEN - 0.25 0.40 0.55 V Burst Mode Feedback Source Current IBFB VFB = 0V 60 100 140 uA Burst Mode Switching Time TBS VFB = 0.9V, Duty =50% 1.2 1.4 1.6 ms Burst Mode Hold Time TBH VFB = 0.9V -> 0V 1.2 1.4 1.6 ms PROTECTION SECTION Shutdown Feedback Voltage VSD VCC = 18V 7.0 7.5 8.0 V Shutdown Delay Current IDELAY VFB = 5V, VCC = 18V 4 5 6 μA Over Voltage Protection VOVP VFB = 3V 11 12 13 V Over Current Latch Voltage (1) VOCL VCC = 18V 0.9 1.0 1.1 V Thermal Shutdown Temp (2) TSD - 140 - - °C FSCQ-SERIES 8 Electrical Characteristics (Continued) (Ta=25°C unless otherwise specified) Note: 1. This parameter is the current flowing in the control IC. 2. These parameters indicate inductor current. 3. These parameters, although guaranteed, are tested only in EDS (wafer test) process. Parameter Symbol Condition Min. Typ. Max. Unit Sync SECTION Sync Threshold in Normal QR (H) VSH1 VCC = 18V, VFB = 5V 4.2 4.6 5.0 V Sync Threshold in Normal QR (L) VSL1 2.3 2.6 2.9 V Sync Threshold in Extended QR (H) VSH2 2.7 3.0 3.3 V Sync Threshold in Extended QR (L) VSL2 1.6 1.8 2.0 V Extended QR Enable Frequency FSYH - 90 - kHz Extended QR Disable Frequency FSYL - 45 - kHz TOTAL DEVICE SECTION Operating Supply Current (1) - In Normal Operation IOP FSCQ0565RT VFB = 5V - 4 6 mA FSCQ0765RT - 4 6 FSCQ0965RT - 6 8 FSCQ1265RT - 6 8 FSCQ1465RT - 7 9 FSCQ1565RT - 7 9 FSCQ1565RP - 7 9 - In Burst Mode (Non-switching) IOB VFB = GND - 0.25 0.50 mA Startup Current ISTART VCC = VSTART-0.1V - 25 50 uA Sustain Latch Current(3) ISN VCC = VSTOP-0.1V - 50 100 uA CURRENT SENSE SECTION Maximum Current Limit (2) ILIM FSCQ0565RT VCC = 18V, VFB = 5V 3.08 3.5 3.92 A FSCQ0765RT 4.4 5 5.6 FSCQ0965RT 5.28 6.0 6.72 FSCQ1265RT 6.16 7 7.84 FSCQ1465RT 7.04 8.0 8.96 FSCQ1565RT 7.04 8 8.96 FSCQ1565RP 10.12 11.5 12.88 Burst Peak Current IBUR(pk) FSCQ0565RT VCC = 18V, VFB = Pulse 0.45 0.65 0.85 A FSCQ0765RT 0.65 0.9 1.15 FSCQ0965RT 0.6 0.9 1.2 FSCQ1265RT 0.8 1.2 1.6 FSCQ1465RT 0.6 0.9 1.2 FSCQ1565RT - 1 - FSCQ1565RP - 1 - FSCQ-SERIES 9 Electrical Characteristics -50 0 50 100 150 0.8 1.0 1.2 Temp[ ]℃ Operating Supply Current N or m al iz ed to 2 5℃ -50 0 50 100 150 0.6 0.8 1.0 1.2 1.4 Temp[ ]℃ Burst-mode Supply Current( Non-Switching) N or m al iz ed to 2 5℃ -50 0 50 100 150 0.6 0.8 1.0 1.2 1.4 Temp[ ]℃ Start-Up Current N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Start Threshold Voltage N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Stop Threshold Voltage N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Initial Frequency N or m al iz ed to 2 5℃ Temp[ ]℃ FSCQ-SERIES 10 Electrical Characteristics -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Maximum Duty Cycle N or m al iz ed to 2 5℃ Temp[ ]℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Over Voltage Protection N or m al iz ed to 2 5℃ -50 0 50 100 150 0.8 0.9 1.0 1.1 1.2 Temp[ ]℃ Shutdown Delay Current N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Shutdown Feedback Voltage N or m al iz ed to 2 5℃ -50 0 50 100 150 0.8 0.9 1.0 1.1 1.2 Temp[ ]℃ Feedback Source Current N or m al iz ed to 2 5℃ -50 0 50 100 150 0.8 0.9 1.0 1.1 1.2 Temp[ ]℃ Burst_mode Feedback Source Current N or m al iz ed to 2 5℃ FSCQ-SERIES 11 Electrical Characteristics -50 0 50 100 150 0.6 0.8 1.0 1.2 1.4 Temp[ ]℃ Burst_Mode Enable Feedback Voltage N or m al iz ed to 2 5℃ -50 0 50 100 150 0.6 0.8 1.0 1.2 1.4 N or m al iz ed to 2 5℃ Temp[ ]℃ Feedback Offset Voltage -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Sync. Threshold in Normal QR(H) N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Sync. Threshold in Normal QR(L) N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Sync. Threshold in Extended QR(H) N or m al iz ed to 2 5℃ -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Temp[ ]℃ Sync. Threshold in Extended QR(L) N or m al iz ed to 2 5℃ FSCQ-SERIES 12 Electrical Characteristics -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 Extended QR Enable Freqency N or m al iz ed to 2 5℃ Temp[℃] -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 N or m al iz ed to 2 5℃ T em p[℃ ] P ulse-by-pulse C urrent L im it -50 0 50 100 150 0.90 0.95 1.00 1.05 1.10 N or m al iz ed to 2 5℃ T em p[℃ ] E xtended Q R D isab le F requency FSCQ-SERIES 13 Functional Description 1. Startup: Figure 4 shows the typical startup circuit and the transformer auxiliary winding for the FSCQ-Series. Before the FSCQ-Series begins switching, it consumes only startup current (typically 25uA). The current supplied from the AC line charges the external capacitor (Ca1) that is connected to the Vcc pin. When Vcc reaches the start voltage of 15V (VSTART), the FSCQ-Series begins switching, and its current consumption increases to IOP. Then, the FSCQ- Series continues its normal switching operation and the power required for the FSCQ-Series is supplied from the transformer auxiliary winding, unless Vcc drops below the stop voltage of 9V (VSTOP). To guarantee the stable operation of the control IC, Vcc has under voltage lockout (UVLO) with 6V hysteresis. Figure 5 shows the relationship between the operating supply current of the FSCQ-Series and the supply voltage (Vcc). Figure 4. Startup circuit Figure 5. Relationship Between Operating Supply Current and Vcc Voltage The minimum average of the current supplied from the AC is given by where Vacmin is the minimum input voltage, Vstart is the FSCQ-Series start voltage (15V), and Rstr is the startup resistor. The startup resistor should be chosen so that Isupavg is larger than the maximum startup current (50uA). Once the resistor value is determined, the maximum loss in the startup resistor is obtained as where Vacmax is the maximum input voltage. The startup resistor should have properly-rated dissipation wattage. 2. Synchronization: The FSCQ-Series employs a quasi- resonant switching technique to minimize the switching noise and loss. In this technique, a capacitor (Cr) is added between the MOSFET drain and the source as shown in Figure 6. The basic waveforms of the quasi-resonant converter are shown in Figure 7. The external capacitor lowers the rising slope of the drain voltage to reduce the EMI caused when the MOSFET turns off. To minimize the MOSFET’s switching loss, the MOSFET should be turned on when the drain voltage reaches its minimum value as shown in Figure 7. Figure 6. Synchronization Circuit FSCQ-Series 1N4007 Rstr Vcc Ca1 Da Isup AC line (Vacmin - Vacmax) CDC Ca2 Icc Vcc Vstop=9V ISTART IOP Vstart=15V Vz Power Up Power Down IOP Value FSCQ0565RT : 4mA (Typ.) FSCQ0765RT : 4mA (Typ.) FSCQ0965RT : 6mA (Typ.) FSCQ1265RT : 6mA (Typ.) FSCQ1465RT : 7mA (Typ.) FSCQ1565RT : 7mA (Typ.) FSCQ1565RP : 7mA (Typ.) Isup avg 2 Vac min⋅ π------------------------------ Vstart 2 --------------–⎝ ⎠⎜ ⎟ ⎛ ⎞ 1 Rstr ----------⋅= Loss 1Rstr ---------- Vac max( )2 Vstart2+ 2 --------------------------------------------------- 2 2 Vstart Vac max⋅ ⋅ π------------------------------------------------------–⎝ ⎠⎜ ⎟ ⎛ ⎞⋅= Vcc Ca1 Da CDC Ca2 GND Cr Drain Ids Rcc RSY1 RSY2 Sync + VDC - Lm Vo CSY + Vds - Vco DSY Np Ns Na Administrator 单位部门，完整姓名，日期 FSCQ-SERIES 14 Figure 7. Quasi-resonant Operation Waveforms The minimum drain voltage is indirectly detected by monitoring the Vcc winding voltage as shown in Figure 6 and 8. Choose voltage dividers, RSY1 and RSY2, so that the peak voltage of the sync signal (Vsypk) is lower than the OVP voltage (12V) to avoid triggering OVP in normal operation. It is typical to set Vsypk to be lower than OVP voltage by 3-4 V. To detect the optimum time to turn on MOSFET, the sync capacitor (CSY) should be determined so that TR is the same with TQ as shown in Figure 8. The TR and TQ are given as, respectively where Lm is the primary side inductance of the transformer, and Ns and Na are the number of turns for the output winding and Vcc winding, respectively, VFo and VFa are the diode forward voltage drops of the output winding and Vcc winding, respectively, and Ceo is the sum of the output capacitance of the MOSFET and the external capacitor, Cr. Figure 8. Normal Quasi-Resonant Operation Waveforms Figure 9. Extended Quasi-Resonant Operation In general, the QRC has a limitation in a wide load range application, since the switching frequency increases as the output load decreases, resulting in a severe switching loss in the light load condition. To overcome this limitation, the FSCQ-Series employs an extended quasi-resonant switching operation. Figure 9 shows the mode change between normal and extended quasi-resonant operations. In the normal quasi- resonant operation, the FSCQ-Series enters into the extended quasi-resonant operation when the switching frequency exceeds 90kHz as the load reduces. To reduce the switching frequency, the MOSFET is turned on when the drain voltage reaches the second minimum level, as shown in Figure 10. VDC VRO VRO IpkIds Vd s Vgs MOSFET Off MOSFET On TR RSY2 CSY Vco 2.6 --------- RSY2 RSY1 RSY2+ -----------------------------------⋅⎝ ⎠⎛ ⎞ln⋅ ⋅= TQ π Lm Ceo⋅⋅= Vco Na Vo VFO+( )⋅ Ns ----------------------------------------- VFa–= Vsync Vds MOSFET Gate 2VR O Vrh (4.6V) Vrf (2.6V) ON TQ TR ON Vsypk Output power Switching frequency Normal QR operation Extended QR operation 90kHz 45kHz Administrator 单位部门，完整姓名，日期 FSCQ-SERIES 15 Once the FSCQ-Series enters into the extended quasi- resonant operation, the first sync signal is ignored. After the first sync signal is applied, the sync threshold levels are changed from 4.6V and 2.6V to 3V and 1.8V, respectively, and the MOSFET turn-on time is synchronized to the second sync signal. The FSCQ-Series returns to its normal quasi- resonant operation when the switching frequency reaches 45kHz as the load increases. Figure 10. Extended Quasi-Resonant Operation Wave- forms 3. Feedback Control: The FSCQ-Series employs current mode control, as shown in Figure 11. An opto-coupler (such as Fairchild’s H11A817A) and shunt regulator (such as Fairchild’s KA431) are typically used to implement the feedback network. Comparing the feedback voltage with the voltage across the Rsense resistor plus an offset voltage makes it possible to control the switching duty cycle. When the reference pin voltage of the KA431 exceeds the internal reference voltage of 2.5V, the H11A817A LED current increases, pulling down the feedback voltage and reducing the duty cycle. This event typically happens when the input voltage is increased or the output load is decreased. 3.1 Pulse-by-Pulse Current Limit: Because current mode control is employed, the peak current through the SenseFET is limited by the inverting input of the PWM comparator (Vfb*) as shown in Figure 11. The feedback current (IFB) and internal resistors are designed so that the maximum cathode voltage of diode D2 is about 2.8V, which occurs when all IFB flows through the internal resistors. Since D1 is blocked when the feedback voltage (Vfb) exceeds 2.8V, the maximum voltage of the cathode of D2 is clamped at this v