FAIRCHILD User Guide for FEBFL7701_L30U003A 2.4W LED Ballast Using FL7701
Summary
Design high-efficiency LED lighting solutions with this comprehensive evaluation guide for building universal-input 2.4W ballasts using the FL7701 IC. This manual is an essential resource detailing the system's operation, including general specifications, schematics, and detailed test waveforms. It provides deep technical insights into performance metrics like Power Factor Correction (PFC), efficiency, and Thermal Performance. Perfect for electrical engineers developing reliable, high-power factor LED drivers.
Page 1 Text Content
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.1.0.2
Page Summary Contents For FAIRCHILD User Guide for FEBFL7701_L30U003A 2.4W LED Ballast Using FL7701
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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 Sem...
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Table of Contents 1. Introduction ............................................................................................................................... 3 1.1. General Description ...........
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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...
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1.3. Internal Block Diagram Figure 1. Internal Block Diagram Pin Descriptions Pin Symbol Description Current Sense. Limits output current, depending on the sensing resistor voltage. The CS pin is also...
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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 Symbol Value Comments VIN...
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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) © 20...
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4. Printed Circuit Board Figure 5. PCB, Top Side Figure 6. PCB, Bottom Side © 2012 Fairchild Semiconductor Corporation 7 FEBFL7701_L30U003A • Rev. 1.0.2
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5. Schematic Figure 7. Schematic of Evaluation © 2012 Fairchild Semiconductor Corporation 8 FEBFL7701_L30U003A • Rev. 1.0.2
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6. Bill of Materials Qty Reference Part Number Value Description Manufacturer PCB Silkscreen Fairchild 1 U1 FL7701 Controller Semiconductor 0.5A / Fairchild 1 BD MB6S Diode, Bridge, 600V, 0.5A 600V Se...
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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,...
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8.2. Operating Frequency & Minimum Duty The programmable switching frequency is between 20k Hz ~ 250k Hz, determined by selecting the RT resistor value. If no RT resistor is used (RT pin OPEN), th...
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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 le...
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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: Figure 18...
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Table 2. Output Characteristics by Input Voltage & Frequency 47Hz 64Hz VLED(RMS) ILED(RMS) VLED(RMS) ILED(RMS) 90VAC 27.91V 84.45m A 27.90V 84.58m A 110VAC 27.99V 84.41m A 28.02V 84.49m A 180VAC 2...
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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 th...
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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 protec...
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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 con...
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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. Efficien...
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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%). TH...
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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 d...
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Figure 34. Thermal Test Result, Bottom-Side Figure 35. Thermal Test Result, Top-Side Temperature Temperature at 220VAC Condition (IC) at 220VAC Condition (Inductor) Figure 36. Thermal Test Result, Bot...
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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. EMI Test Results, Conducte...
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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 Loa...
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10. Revision History Rev. Date Description 0.0.1 2011.11.16 First issue 1.0.1 2011.11.30 Update IC temperature Modified, edited, formatted document. Changed User Guide number from FEB_L030 to FEBFL770...
Manual Details
| Brand | Fairchild |
|---|---|
| Pages | 24 |
| File Size | 2.75 MB |
| Published | June 20, 2026 |
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Frequently Asked Questions
What is the input voltage range for this LED ballast?
The document specifies an application input range of 80V ~ 308V AC, and notes a general input range of 90V – 265V.
Does the FL7701 require a bulk capacitor?
No, the FL7701 is designed not to require a bulk (electrolytic) capacitor for supply rail stability.
What function does the IC perform when AC and DC inputs are applied?
It automatically enables PFC function when an AC input voltage is detected, but disables it if a DC input is applied.
How can I ensure I am using genuine parts?
Purchase Fairchild parts directly from Fairchild or from an Authorized Fairchild Distributor to guarantee authenticity and traceability.