FL7701 Smart LED Lamp Driver IC with PFC Function Features Description Digitally Implemented Active PFC Function (No Additional Circuit Necessary for High PF) Built-in HV Supplying Circuit: Self Biasing The FL7701 LED lamp driver is a simple IC with PFC function. The special “adopted digital” technique of the IC can automatically detect input voltage condition and send an internal reference signal for achieving high power factor. When AC input is applied to the IC, PFC function is automatically enabled. Otherwise, when DC input is applied to the IC, PFC function is automatically disabled. The FL7701 does not need a bulk capacitor (electrolytic capacitor) for supply rail stability, which can significantly affect to LED lamp system. Application Input Range: 80 VAC ~ 308 VAC AOCP Function with Auto-Restart Mode Built-in Over-Temperature Protection Function Cycle-by-Cycle Current Limit Current-Sense Pin Open Protection Low Operating Current: 0.85 mA (Typical) Related Resources Under-Voltage Lockout with 5 V Hysteresis Evaluation Board: FEBFL7701_L30U003A Programmable Oscillation Frequency Programmable LED Current Analog Dimming Function Soft-Start Function Precise Internal Reference: ±3% Applications LED Lamp for Decorative Lighting LED Lamp for Low-Power Lighting Ordering Information Part Number Operating Temperature Range Package Packing Method FL7701MX -40°C to +125°C 8-Lead, Small Outline Integrated Circuit (SOIC), JEDEC MS-012, .150-inch Narrow Body Tape & Reel © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com FL7701 — Smart LED Lamp Driver IC with PFC Function June 2013 BD L1 LED D1 L3 Fuse C2 C1 CS HV OUT NV VCC GND D2 Q1 R2 ADIM RT C3 R1 U1 C4 R3 L2 Figure 1. Typical Application Block Diagram VCC 3 JFET VCC 8 HV ZCD UVLO time IAD ADIM ZCD 5 DAC TSD Soft start Digital Block RT 4 S Oscillator 2 OUT Q R Reference + 1 LEB GND 6 CS Leading Edge Blanking + AOCP 2.5V Figure 2. Block Diagram © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 2 FL7701 — Smart LED Lamp Driver IC with PFC Function Application Diagram CS VCC FL7701 OUT HV NV GND RT ADIM Figure 3. Pin Configuration Pin Definitions Pin # Name Description 1 CS Current Sense. Limits output current depending on the sensing resistor voltage. The CS pin is also used to set the LED current regulation 2 OUT OUT. Connects to the MOSFET gate. 3 VCC VCC. Supply pin for stable IC operation ZCD signal detection used for accurate PFC function. 4 RT 5 ADIM Analog Dimming. Connect to the internal current source and can change the output current using an external resistor. If ADIM is not used, it is recommended to connect a 0.1 µF bypass capacitor between the ADIM and GND. 6 GND GROUND. Ground for the IC. 7 NC No Connection 8 HV High Voltage. Connect to the high voltage line and supply current to the IC RT. Programmable operating frequency using external resistor and the IC has pre-fixed frequency when this pin is open or floating. © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 3 FL7701 — Smart LED Lamp Driver IC with PFC Function 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. Symbol Parameter Min. Max. Unit V VCC IC Supply Voltage 20 HV High Voltage Sensing 500 V IO+/IO- Peak Drive Output Current (Sourcing / Sinking) 250 mA VADIM Analog Dimming 5 V VRT RT Pin Voltage 5 V VCS Allowable Current Sensing Detection Voltage 5 V TA Operating Ambient Temperature Range -40 +125 C TJ Operating Junction Temperature -40 +150 C -65 +150 C 135 C/W 660 mW TSTG Storage Temperature Range θJA Thermal Resistance Junction-Air PD Power Dissipation ESD (1,2) Electrostatic Discharge Capability Human Body Model, JESD22-A114 2000 Charged Device Model, JESD22-C101 1000 V Notes: 1. Thermal resistance test board. Size: 76.2 mm x 114.3 mm x 1.6 mm (1S0P); JEDEC standard: JESD51-2, JESD513. 2. Assume no ambient airflow. © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 4 FL7701 — Smart LED Lamp Driver IC with PFC Function Absolute Maximum Ratings Typical values are at TA = +25°C. Specifications to -40°C ~ 125°C are guaranteed by design based on final characterization results. Symbol Parameter Conditions Min. Typ. Max. Unit VCC Bias Section VCC VCC Regulator Output Voltage VHV=100 VDC 14.0 15.5 17.0 V VCCST+ UVLO Positive Going Threshold VCC Increasing 12 13 14 V VCCST- UVLO Negative Going Threshold VCC Decreasing 7 8 9 V VCCHY UVLO Hysteresis 4 5 6 V 0.85 1.10 mA 120 150 μA VHV=100 VDC, CL=150 pF, RT=Open IHV HV Pin Current IST Startup Current Switching Section fOSC tMIN DMAX Operating Frequency RT=5.95 kΩ 200 250 300 kHz RT=87 kΩ 16 20 24 kHz RT Open 40.5 45.0 49.5 kHz Minimum On Time Maximum Duty Cycle tLEB Leading Edge Blanking Time VRT Voltage Reference of RT pin (3) 400 ns 50 % 350 ns 1.5 V Soft-Start Section tss Soft-Start Time DC Mode (3) 48 AC Mode 60 72 ms 7 Periods Reference Section VCS1 Internal Reference Voltage of CS Pin VCS2 DC Mode AC Mode (3) 0.354 0.365 0.376 0.485 0.500 0.515 17.7 18.7 19.7 V Protection Section OVPVCC VAOCP tAOCP Over-Voltage Protection on VCC Pin Abnormal OCP Level at CS Pin Abnormal Detection Time (3) (3) tTSDH Thermal Shutdown Threshold tTSDHY Thermal Shutdown Threshold (3) Hysteresis (3) 140 Dimming Section Analog Dimming Positive Going VADIM(ST+) (3) Threshold Analog Dimming Negative Going VADIM(ST-) (3) Threshold IAD 3.15 Internal Current Source for ADIM Pin 9 V 2.5 V 70 ns 150 °C 50 °C 3.50 3.85 V 0.50 0.75 V 12 15 μA Note: 3. These parameters, although guaranteed, are not 100% tested in production. © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 5 FL7701 — Smart LED Lamp Driver IC with PFC Function Electrical Characteristics The FL7701 is a basic PWM controller for buck converter topology in Continuous Conduction Mode (CCM) with intelligent PFC function using a digital control algorithm. The FL7701 has an internal selfbiasing circuit that uses the high-voltage switching device. The IC does not need an auxiliary powering path to the VCC pin typical in flyback control ICs or PSR product family. power for the IC, has voltage ripple as well as the rectification voltage after bridge, changing voltage level according to the VCC capacitor value. Using this kind of voltage fluctuation on the VCC pin, the IC can detect the time reference and create the internal ZCD signal. For precise and reliable internal reference for input voltage signal, the FL7701 uses a digital technique (sigma/delta modulation) and creates a new internal signal (DAC_OUT) that has the same phase as the input voltage, as shown in Figure 5. This signal enters the final comparator and is compared with current information from the sensing resistor. When the input voltage applied to the HV pin is over 25 V to 500 V, the FL7701 maintains a 15.5 V DC voltage at the VCC pin for stable operation. The FL7701 has UVLO block functions such that when the VCC voltage rises higher than VCCST+, the internal UVLO block releases and starts operation. Otherwise the VCC goes down to the VCCST- and IC operation stops. Normally, the hysteresis function provides stable operation even if the input voltage is operating under the very noisy or unstable circumstances. Vbridge Bridge Diode Output Voltage Input Voltage Peak JFET Output Voltage t Vdd Charging Voltage VCC The FL7701 has a smart internal digital block for determining input condition: AC or DC. When an AC source with 50 Hz or 60 Hz is applied to the IC, the IC automatically changes its internal reference signal, which is similar to input signal, for creating high power factor. Otherwise, once the DC source connects to the IC, the internal reference immediately changes to DC. JFET Output Voltage t ZCD t DAC_OUT t 1. Soft-Start Function Figure 5. Internal PFC Function The FL7701 has an internal soft-start function to reduce inrush current at startup. When the IC starts operation following an internal sequence, the internal reference slowly increases for a pre-determined fixed time. After this transient period, the internal reference goes to a steady-state level. In this time, the IC continually tries to find phase information from the VCC pin. If the IC succeeds in getting phase information, it automatically follows a similar shape reference made during the transient times, 7 periods. If not, the IC has a DC reference level. 3. Self-Biasing Function The self-biasing function, using an HV device, can supply enough operating current to the IC and guarantee similar startup time across the whole input voltage range (80 V~308 VAC). However, self-biasing has a weakness in high-voltage condition. Normally, the HV device acts as constant current source, so the internal HV device has power loss when high input voltage connects to the HV pin. This power loss is proportional to input voltage. To reduce this power loss, one of the possible solutions is an additional resistor between the input voltage source and the HV pin, as shown in Figure 6. Vbridge Bridge Diode EMI filter ILED U1 T/2 = 1/(Input Frequency * 2) 7*(T/2) Normal Operation ADIM RT Figure 4. Soft Starting Function in AC Input Mode VCC HV OUT CS GND 2. Internal PFC Function: How to Achieve High Power Factor Figure 6. High-Voltage Application The FL7701 has a simple, but smart, internal PFC function that does not require additional detection pins for detecting input phase information or an electrolytic capacitor for supply voltage stabilization. For achieving high PF, the FL7701 does not use the rectification capacitor after the bridge diode. This is important because the IC instead uses fluctuation in the signal on the VCC pin. Basically, the VCC pin, which is supplies © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 6 FL7701 — Smart LED Lamp Driver IC with PFC Function Functional Description In DCM Mode, inductance is: The FL7701 uses the ADIM pin for analog or 0 V to 10 V dimming by using a resistive divider. The peak voltage of internal reference, which is DAC_OUT signal in Figure 5, is changed by the VADIM level, as shown in Figure 7, and has different peak level according to the operating mode. Lm n V f (1 Dmin ) f s i rip I LED ( ave. peak) icon AC mode I LED ( rms) 0. 5 V 3 . 5V irip [A] (3) 2 In FL7701, the LED RMS current determines the inductance parameter. To drive for CCM Mode, define LED RMS current first, as: DC mode 0.365V (2) If the peak current is fixed at 350 mApk, the formula for the peak current is: VDAC _ OUT 0 .5 V [H ] I LED ( ave. peak) [A] 2 (4) Substituting Equation (2) for Equation inductance of inductor is obtained. VADIM (4), the Figure 7. VADIM vs. VDAC_OUT(peak) VIN 5. Inductor Design Π The FL7701 prefixed internal duty ratio range is below 50%, or around 400 ns, from timing point of view. The range is dependent on the input voltage and LED numbers in its string. Dmin 4Π t Bridge Diode Output Voltage Vbridge Input Voltage Peak Minimum duty is calculated as: 3Π 2Π Vdd Charging Voltage t ZCD t n V f DAC (1) Vin (max) t VLED where: η is efficiency of system; VIN(max) is maximum input voltage; Vf is forward drop voltage of LED; and n is LED number in series connection. Vdrain t Input Voltage Peak t ILED Input Voltage Peak Current Limit Average LED Current t ∆irip IFRD t IMOSFET ton toff Dmin 1-Dmin (a) DCM Mode t Iinput Current peak at LED current maximum point (ILED(peak)) Current peak at LED average current maximum point (ILED(ave.peak)) DCM Average LED Current (ILED(ave)) ∆i 0.5∆i t DCM T/2 = 1/(Input Frequency * 2) 0.5∆i T = 1/Input Ferquency Figure 9. Typical Performance Characteristics CCM Current min at LED current maximum point (ILED(min)) Dmin 1-Dmin ton toff (b) CCM Mode Figure 8. DCM and CCM Operation © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 7 FL7701 — Smart LED Lamp Driver IC with PFC Function 4. Dimming Function FL7701 — Smart LED Lamp Driver IC with PFC Function Example Application Circuits BD L1 LED D1 L3 Fuse C2 C1 CS HV OUT NV VCC GND D2 Q1 R2 ADIM RT C3 U1 R1 C4 R3 L2 Figure 10. Application without an Electrolytic Capacitor BD L1 LED C5 D1 L3 Fuse C2 C1 CS HV OUT NV VCC GND D2 Q1 R2 RT C3 R1 ADIM U1 C4 R3 L2 Figure 11. Application with an Electrolytic Capacitor © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 8 17.0 6.0 5.5 VCC HY [V ] VCC [V ] 16.5 16.0 15.5 15.0 5.0 4.5 14.5 14.0 -40 -20 0 20 40 60 80 100 4.0 -40 120 -20 0 Temperature [°C] 40 60 80 100 120 Temperature [°C] Figure 12. VCC vs. Temperature Figure 13. VCCHY vs. Temperature 14.0 150 140 IST [uA ] VCC ST+ [V ] 13.5 130 13.0 120 12.5 110 12.0 -40 -20 0 20 40 60 Temperature [°C] 80 100 100 -40 120 -20 0 20 40 60 80 100 120 Temperature [°C] Figure 14. VCCST+ vs. Temperature Figure 15. IST vs. Temperature 9.0 50 48 8.5 fOSC [kHz] VCC ST- [V ] 20 8.0 46 44 7.5 42 7.0 -40 -20 0 20 40 60 Temperature [°C] 80 100 120 -40 Figure 16. VCCST- vs. Temperature © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 -20 0 20 40 60 Temperature [°C] 80 100 120 Figure 17. fOSC vs. Temperature (Rt=Open) www.fairchildsemi.com 9 FL7701 — Smart LED Lamp Driver IC with PFC Function Typical Characteristics 52 22 51 D MAX fOSC [kHz] 24 20 49 18 16 -40 50 -20 0 20 40 60 80 100 48 -40 120 -20 0 Temperature [°C] 20 40 60 80 100 120 Temperature [°C] Figure 19. DMAX vs. Temperature Figure 18. fOSC vs. Temperature (Rt=87 kΩ) 1.7 300 280 fOSC [kHz] 1.6 V RT 260 1.5 240 1.4 220 200 -40 -20 0 20 40 60 80 100 1.3 -40 120 Temperature [°C] -20 0 20 40 60 80 100 120 Temperature [°C] Figure 21. VRT vs. Temperature Figure 20. fOSC vs. Temperature (Rt=5.95 kΩ) 500 0.376 0.372 V CS1 TMIN 450 400 0.368 0.364 0.360 350 0.356 300 -40 -20 0 20 40 60 Temperature [°C] 80 100 -40 120 Figure 22. tMIN vs. Temperature © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 -20 0 20 40 60 Temperature [°C] 80 100 120 Figure 23. VCS1 vs. Temperature www.fairchildsemi.com 10 FL7701 — Smart LED Lamp Driver IC with PFC Function Typical Characteristics 15 19.5 19.0 IAD[uA] OVP VCC 14 18.5 13 12 11 10 18.0 -40 -20 0 20 40 60 80 100 9 120 Figure 24. OVPVCC vs. Temperature © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 -40 -20 0 20 40 60 80 100 120 Temperature [°C] Temperature [°C] Figure 25. . IAD vs. Temperature www.fairchildsemi.com 11 FL7701 — Smart LED Lamp Driver IC with PFC Function Typical Characteristics FL7701 — Smart LED Lamp Driver IC with PFC Function Physical Dimensions 5.00 4.80 A 0.65 3.81 8 5 B 1.75 6.20 5.80 PIN ONE INDICATOR 4.00 3.80 1 5.60 4 1.27 (0.33) 1.27 0.25 C B A LAND PATTERN RECOMMENDATION SEE DETAIL A 0.25 0.10 0.25 0.19 C 1.75 MAX 0.10 0.51 0.33 OPTION A - BEVEL EDGE 0.50 x 45° 0.25 R0.10 GAGE PLANE R0.10 OPTION B - NO BEVEL EDGE 0.36 NOTES: UNLESS OTHERWISE SPECIFIED 8° 0° 0.90 0.40 A) THIS PACKAGE CONFORMS TO JEDEC MS-012, VARIATION AA. B) ALL DIMENSIONS ARE IN MILLIMETERS. C) DIMENSIONS DO NOT INCLUDE MOLD FLASH OR BURRS. D) LANDPATTERN STANDARD: SOIC127P600X175-8M. E) DRAWING FILENAME: M08Arev14 F) FAIRCHILD SEMICONDUCTOR. SEATING PLANE (1.04) DETAIL A SCALE: 2:1 Figure 26. 8-Lead, Small-Outline Integrated Circuit (SOIC), JEDEC MS-012, .150-Inch Narrow 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/. © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 12 FL7701 — Smart LED Lamp Driver IC with PFC Function © 2011 Fairchild Semiconductor Corporation FL7701 • Rev. 1.0.4 www.fairchildsemi.com 13