User Guide for FEBFL7701_L30U003A 2.4W LED Ballast Using FL7701 Featured Fairchild Product: FL7701 Direct questions or comments about this evaluation board to: “Worldwide Direct Support” Fairchild Semiconductor.com © 2012 Fairchild Semiconductor Corporation 1 FEBFL7701_L30U003A • Rev.1.0.
Table of Contents 1. Introduction ............................................................................................................................... 3 1.1. 1.2. 1.3. General Description.......................................................................................................... 3 Key Features ..................................................................................................................... 3 Internal Block Diagram ................................................
This user guide supports the Evaluation kit for the FL7701. It should be used in conjunction with the FL7701 datasheet as well as Fairchild’s application notes and technical support team. Please visit Fairchild’s website at www.fairchildsemi.com. 1. Introduction This document describes the proposed solution for a universal-input 2.4W LED ballast using the FL7701. The input voltage range is 90VRMS – 265VRMS and there is one DC output with a constant current of 85mA at 28VMAX.
1.3. Internal Block Diagram Figure 1. Internal Block Diagram Pin Descriptions Pin Symbol 1 CS 2 OUT Output. Connects to the MOSFET gate. 3 VCC Supply Voltage. Supply pin for stable IC operation; ZCD signal detection used for accurate PFC function. 4 RT Resistor. Programmable operating frequency using an external resistor connected to this PIN and the IC has fixed frequency when this pin is left open or floating. 5 ADIM Analog Dimming.
2. General Specifications for Evaluation Board All data for this table was measured at an ambient temperature of 25°C Table 1. Summary of Features and Performance Description Input Voltage Range AC Input Frequency Output Voltage/Current Output Power Symbol Value VIN,min 90V VIN,nom 220V VIN,max 265V fIN,min 47Hz fIN,max 64Hz VOUT 28V IOUT 85mA Output Power 2.41W Note 2 >78% At full load Efficiency Temperature Comments TFL7701 < 71.5°C TMOSFET < 59.5°C TINDUCTOR < 57.
3. Photographs of the Evaluation Board Figure 2. Photograph Top View (20mm x 32mm x 13mm) Figure 3. Photograph Bottom View (20mm x 32mm x 13mm) Figure 4. Photograph Side View (20mm x 32mm x 13mm) © 2012 Fairchild Semiconductor Corporation 6 FEBFL7701_L30U003A • Rev. 1.0.
4. Printed Circuit Board Figure 5. PCB, Top Side Figure 6. PCB, Bottom Side © 2012 Fairchild Semiconductor Corporation 7 FEBFL7701_L30U003A • Rev. 1.0.
5. Schematic Figure 7. Schematic of Evaluation © 2012 Fairchild Semiconductor Corporation 8 FEBFL7701_L30U003A • Rev. 1.0.
6. Bill of Materials Qty Reference Part Number Value Description Manufacturer Controller Fairchild Semiconductor PCB Silkscreen 1 U1 FL7701 1 BD MB6S 0.5A / 600V Diode, Bridge, 600V, 0.5A Fairchild Semiconductor 1 C1 MPE 630V223K 22nF Capacitor, 630VAC, 10%, Polypropylene Sungho C1 1 C2 MPE 630V333K 33nF Capacitor, 630VAC, 10%, Polypropylene Sungho C2 1 C3 C0805C101K3RACTU 100pF Capacitor, SMD, Ceramic, 25V, X7R Kemet ADIM 1 C4 C1206C225K3PACTU 2.
8. Test Waveforms 8.1. Typical Waveforms: Startup Figure 8 through Figure 11 show the typical startup performance at different input voltage conditions. When AC input voltage is applied to the system, the FL7701 automatically operates in AC Mode after finishing an internally fixed, seven-cycle, softstart period. Figure 10 and Figure 11 show the soft-start characteristics when a DC input voltage is applied. CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED Figure 8.
8.2. Operating Frequency & Minimum Duty The programmable switching frequency is between 20kHz ~ 250kHz, determined by selecting the RT resistor value. If no RT resistor is used (RT pin OPEN), the FL7701 default switching frequency is set to 45kHz. The maximum duty ratio is fixed below 50% and has a fixed minimum typical on-time of 400ns. There are two crucial points to design properly.
8.3. Typical Waveforms: Steady State Figure 13 through Figure 22 show the normal operation waveform by input voltage & input frequency. The output voltage and current maintains a certain output level with 120Hz ripple, as shown in the test results in Table 2. CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED Figure 13. Input Voltage: 90VAC, Input Frequency: 47Hz Figure 14.
Typical Operating Waveforms: Output Characteristics CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED Figure 17. Input Voltage: 180VAC, Input Frequency: 47Hz Figure 18. Input Voltage: 180VAC, Input Frequency: 64Hz CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED Figure 19. Input Voltage: 220VAC, Input Frequency: 47Hz Figure 20.
Table 2. Output Characteristics by Input Voltage & Frequency 47Hz 64Hz VLED(RMS) ILED(RMS) VLED(RMS) ILED(RMS) 90VAC 27.91V 84.45mA 27.90V 84.58mA 110VAC 27.99V 84.41mA 28.02V 84.49mA 180VAC 28.13V 84.94mA 28.10V 84.86mA 220VAC 28.12V 85.66mA 28.14V 85.77mA 265VAC 28.17V 87.05mA 28.13V 87.05mA © 2012 Fairchild Semiconductor Corporation 14 FEBFL7701_L30U003A • Rev. 1.0.
8.4. Typical Waveforms: Abnormal Mode (LED Open) Figure 23 and Figure 24 show the open-load condition test method and result. When the LED disconnects from the system, the IC cannot operate because the HV pin is disconnected. Figure 23. Open-Load Condition Test CH1: VCC, CH2: VDRAIN, CH3: VLED, CH4: ILED Figure 24. © 2012 Fairchild Semiconductor Corporation Test Results of Open-Load Condition 15 FEBFL7701_L30U003A • Rev. 1.0.
8.5. Typical Waveforms: Abnormal Mode (Inductor Short Condition) Figure 25 and Figure 26 show the test method and result of an inductor short condition. The FL7701 uses an abnormal over-current protection (AOCP) function, limiting the current on RCS in the event of an inductor short condition. Figure 25. Inductor Short Condition When CS pin voltage reached 2.5V, AOCP operates after internal delay time 70ns (typical) CH1: VCS, CH2: VDRAIN, CH3: VLED, CH4: ILED Figure 26.
9. Performance of Evaluation Board 9.1. Power Factor at Rated Load Condition Figure 27 shows the system PF performance for the entire input voltage range (90V to 265V) at different input frequency conditions (47Hz, 64Hz). The PF slightly changes according to the input frequency but can achieve over 86% at 265VAC condition. 100 95 90 85 80 [%] 75 PF_47Hz 70 PF_64Hz 65 60 55 50 90 110 180 220 264 [VAC] Figure 27. Power Factor Table 3.
9.2. System Efficiency Figure 28 shows system efficiency results for different AC input voltage frequency conditions. As shown, the input frequency has negligible effect on system efficiency. 100 95 90 85 80 [%] Efficiency_47Hz 75 Efficiency_64Hz 70 65 60 55 50 90 110 180 220 264 [VAC] Figure 28. System Efficiency Table 4. Efficiency Test Results Input Voltage 90VAC 110VAC 180VAC 220VAC 265VAC © 2012 Fairchild Semiconductor Corporation 18 Frequency Efficiency (%) 47Hz 83.56 64Hz 83.
9.3. THD Performance Figure 29 shows the THD performance at different input frequencies. Test results are quite similar, except the 90VAC condition, but meets international regulations (under 30%). 30 25 [%] 20 THD_47Hz 15 THD_64Hz 10 5 0 90 110 180 220 264 [VAC] Figure 29. THD Performance Table 5. THD Test Results Input Voltage 90VAC 110VAC 180VAC 220VAC 265VAC © 2012 Fairchild Semiconductor Corporation 19 Frequency THD (%) 47Hz 20.99 64Hz 21.82 47Hz 22.26 64Hz 22.46 47Hz 24.
9.4. Thermal Performance Figure 30 through Figure 37 show the steady-state thermal results with different input voltage conditions. Inductor L3 has the highest temperature on the top side of the PCB due to copper resistance. The FL7701 has the highest temperature on the bottom side of the PCB due to power loss associated with the high-voltage device. The IC temperature is 66.5°C for the 220VAC input condition. Figure 30. Thermal Test Result, Bottom-Side Temperature at 90VAC Condition (IC) Figure 31.
Figure 34. Thermal Test Result, Bottom-Side Temperature at 220VAC Condition (IC) Figure 35. Thermal Test Result, Top-Side Temperature at 220VAC Condition (Inductor) Figure 36. Thermal Test Result, Bottom-Side Temperature at 264VAC Condition (IC) Figure 37. Thermal Test Result, Top-Side Temperature at 264VAC Condition (Inductor) Table 6. Temperature performance by Input voltage Input Voltage TIC TMOSFET TINDUCTOR 90VAC 47.6°C 46.2°C 47.8°C 110VAC 51.4°C 46.9°C 47.8°C 220VAC 66.5°C 55.
9.5. EMI Results EMI test measurements were conducted in observance of CISPR22 criteria, which has tighter stricter limits than CISPR15 for lighting applications. Figure 38. Figure 39. © 2012 Fairchild Semiconductor Corporation EMI Test Results, Conducted Emission-Line at 110VAC Input Condition, Full Load (10-LED Series) EMI Test Results, Conducted Emission-Neutral at 110VAC Input Condition, Full Load (10-LED Series) 22 FEBFL7701_L30U003A • Rev. 1.0.
Figure 40. EMI Test Results, Conducted Emission-Neutral at 220VAC Input Condition, Full Load (10-LED Series) Figure 41. EMI Test Results, Conducted Emission-Neutral at 220VAC Input Condition, Full Load (10-LED Series) © 2012 Fairchild Semiconductor Corporation 23 FEBFL7701_L30U003A • Rev. 1.0.
10. Revision History Rev. Date 0.0.1 2011.11.16 1.0.1 2011.11.30 Update IC temperature 2012.2.20 Modified, edited, formatted document. Changed User Guide number from FEB_L030 to FEBFL7701_L30U003A 1.0.2 Description First issue WARNING AND DISCLAIMER Replace components on the Evaluation Board only with those parts shown on the parts list (or Bill of Materials) in the Users’ Guide. Contact an authorized Fairchild representative with any questions.
