Datasheet FEBFL7701 Datasheet (Fairchild)

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”

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Table of Contents

1. Introduction ............................................................................................................................... 3

1.1. General Description .......................................................................................................... 3

1.2. Key Features ..................................................................................................................... 3

1.3. Internal Block Diagram .................................................................................................... 4

2. General Specifications for Evaluation Board ........................................................................... 5

3. Photographs of the Evaluation Board ....................................................................................... 6

4. Printed Circuit Board ................................................................................................................ 7

5. Schematic .................................................................................................................................. 8

6. Bill of Materials ........................................................................................................................ 9

7. Test Condition & Test Equipment ............................................................................................ 9

8. Test Waveforms ...................................................................................................................... 10

8.1. Typical Waveforms: Startup .......................................................................................... 10

8.2. Operating frequency & minimum duty .......................................................................... 11

8.3. Typical waveforms: Steady State ................................................................................... 12

8.4. Typical waveforms: Abnormal Mode(LED Open) ........................................................ 15

8.5. Typical waveforms: Abnormal Mode (Inductor Short Condition) ................................ 16

9. Performance of Evaluation Board ........................................................................................... 17

9.1. Power Factor at Rated Load Condition .......................................................................... 17

9.2. System Efficiency .......................................................................................................... 18

9.3. THD Performance .......................................................................................................... 19

9.4. Thermal Performance ..................................................................................................... 20

9.5. EMI Results .................................................................................................................... 22

10.Revision History ..................................................................................................................... 24

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 90V output with a constant current of 85mA at 28V description of FL7701, the power supply specification, schematic, bill of materials, and the typical operating characteristics.

1.1. General Description

The FL7701 LED lamp driver is a simple IC with PFC function. The special “adopted digital” technique automatically detects input voltage condition and sends an internal reference signal, resulting in high power factor. When an AC input voltage is applied to the IC, the PFC function is automatically enabled. Otherwise, when a DC input is applied to the IC, the PFC function is automatically disabled. The FL7701 does not require a bulk capacitor (electrolytic capacitor) for supply rail stability, which can significantly affect LED reliability.

– 265V

RMS

. This document contains general

MAX

and there is one DC

RMS

.

1.2. Key Features

 Digitally Implemented Active PFC Function  Built-in Self-Biasing HV Startup Circuit  Application Input Range: 80V  AOCP Function with Auto-Restart Mode  Built-in Over-Temperature Protection  Cycle-by-Cycle Current Limit  Current-Sense Pin Open Protection  Low Operating Current: 0.85mA (Typical)  Under-Voltage Lockout with 5V Hysteresis  Programmable Oscillator Frequency  Programmable LED Current  Analog Dimming Function  Fixed Soft-Start Function  Precise Internal Reference: ±3%

~ 308VAC

AC

1.3. Internal Block Diagram

Figure 1. Internal Block Diagram

Pin Descriptions

Pin Symbol Description

1 CS 2 OUT 3 VCC

4 RT

5 ADIM

6 GND 7 NC No Connection 8 HV

Current Sense. Limits output current, depending on the sensing resistor voltage. The CS pin is also used to set the LED current regulation.

Output. Connects to the MOSFET gate. Supply Voltage. Supply pin for stable IC operation; ZCD signal detection used

for accurate PFC function. 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.

Analog Dimming. Connects to the internal current source and can change the output current using an external resistor. If ADIM is not used, connect a 0.1µF bypass capacitor between ADIM and GND.

GROUND. Ground for the IC.

High Voltage. Connect to the high-voltage line and supply current to the IC

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

V

90V

IN,min

Input Voltage Range

AC Input Frequency

Output Voltage/Current

Output Power Output Power 2.41W Note 2 Efficiency >78% At full load

Temperature

PCB Size

Initial Application LED bulb

Notes:

1. The output current has I

parallel with the LED. Ensure the capacitor voltage rating is high enough to withstand an open-LED condition or use a Zener diode for protection.

2. The output power is not equal to the apparent power due to the slight phase shift between the output

voltage and current.

V

220V

IN,nom

V

265V

IN,max

f

47Hz

IN,min

f

64Hz

IN,max

V

28V Note 1

OUT

I

85mA

OUT

< 71.5°C

T

FL7701

T

MOSFET

T

INDUCTOR

< 59.5°C

< 57.5°C

At full load (all at open frame, room temperature / still air)

20mm (width) x 32mm (length) x 13mm (height)

ripple. To reduce ripple current, use a large electrolytic capacitor in

LEDPK

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)

4. Printed Circuit Board

Figure 5. PCB, Top Side

Figure 6. PCB, Bottom Side

5. Schematic

Figure 7. Schematic of Evaluation

6. Bill of Materials

Qty Reference Part Number Value Description Manufacturer PCB Silkscreen

1

1 2

1 1

U1 FL7701 Controller

BD MB6S

C1

C2

C3

C4

D1 UF4007

D2 1N4148

L1, L2 R06153KT00 15mH Inductor, Radial, R6.5x7.5 Bosung L1, L2

L3 R06402KT00 4mH Inductor, Radial, R6.5x7.5 Bosung L3 R1

MPE 630V223K

MPE 630V333K

C0805C101K3RACTU

C1206C225K3PACTU

RC1206JR-07680RL

0.5A / 600V

22nF

33nF

100pF

2.2µF

1A / 1kV

1A /

100V

680R Resistor,SMD,1/4W,1206 Yageo

Diode, Bridge, 600V, 0.5A

Capacitor, 630V

Polypropylene

Capacitor, 630V

Polypropylene

Capacitor, SMD, Ceramic,

25V, X7R

Capacitor, SMD, Ceramic,

25V, X7R

Diode, 1kV, 1A Ultra-Fast

Recovery

100V/1A, Small-Signal

Diode

, 10%,

AC

, 10%,

AC

Fairchild

Semiconductor

Fairchild

Semiconductor

Sungho C1

Sungho C2

Kemet ADIM

Kemet VCC

Fairchild

Semiconductor

Fairchild

Semiconductor

FRD

4148

1 1 1 1

R2 R3 R4 R5

RC1206JR-0710KL

RC0805JR-0724KL

RC0805JR-07510RL

RC1206JR-073RL

10k Resistor,SMD,1/4W,1206 Yageo 24k Resistor,SMD,1/8W,0805 Yageo RT

510R Resistor,SMD,1/8W,0805 Yageo RG

3.0R Resistor,SMD,1/4W,1206 Yageo RCS

7. Test Condition & Test Equipment

Evaluation Board

Test Date

Test Temperature

Test Equipments

FEBFL7701_L30U003A

2012.01.19 TA = 25°C

AC Source: PCR500L by Kikusui Power Meter: PZ4000 by Yokogawa Oscilloscope: Waverunner 64Xi by Lecroy EMI Test Receiver: ESCS30 by ROHDE & SCHWARZ Two-Line V-Network: ENV216 by ROHDE & SCHWARZ Thermometer: CAM SC640 by FLIR SYSTEMS LED: EHP-AX08EL/GT01H-P03 (3W) by Everlight

8. Test Waveforms

V

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:

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 8. Soft-Start Characteristics, AC Mode, 90V

CH1: VCC, CH2:

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 10. Soft-Start Characteristics, DC Mode, 100V

CH1: VCC, CH2:

Figure 9. Soft-Start Characteristics, AC Mode, 265V

AC

CH1: VCC, CH2:

Figure 11. Soft-Start Characteristics, DC Mode, 200V

DC

DRAIN

, CH3: V

LED

, CH4: I

LED

AC

LED

DC

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. The first is consideration of the minimum duty ratio at minimum input voltage because the FL7701 is limited to 50% duty ratio. The second consideration is minimum on-time at maximum input voltage condition. The FL7701 cannot control output power when the operating conditions are such that the required on-time is less than the 400ns minimum on-time.

Minimum on time:

1.12µs

Switching frequency:

69.91kHz

CH1: V

Figure 12. Operating Frequency & Minimum Duty

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

8.3. Typical Waveforms: Steady State

V

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:

Figure 13. Input Voltage: 90VAC, Input Frequency: 47Hz

DRAIN

, CH3: V

LED

, CH4: I

LED

H1: VCC, CH2: V

Figure 15. Input Voltage: 110V

DRAIN

47Hz

, CH3: V

AC

LED

, CH4: I

LED

, Input Frequency:

CH1: V

Figure 14. Input Voltage: 90VAC, Input Frequency: 64Hz

Figure 16. Input Voltage: 110V

H1: V

, CH2:

CC

, CH2: V

DRAIN

, CH3: V

64Hz

, CH4: I

LED

, Input Frequency:

AC

, CH4: I

LED

Typical Operating Waveforms: Output Characteristics

V

CH1:

Figure 17. Input Voltage: 180VAC, Input Frequency:

, CH2:

CC

DRAIN

47Hz

, CH3:

LED

, CH4: I

LED

CH1:

, CH2:

CC

Figure 18. Input Voltage: 180VAC, Input Frequency:

DRAIN

64Hz

, CH3:

LED

, CH4: I

LED

CH1:

, CH2:

CC

DRAIN

, CH3:

LED

, CH4: I

LED

Figure 19. Input Voltage: 220VAC, Input Frequency:

47Hz

H1: V

Figure 21. Input Voltage: 265V

, CH2: V

CC

DRAIN

, CH3: V

AC

LED

, CH4: I

LED

, Input Frequency:

47Hz

CH1:

, CH2:

CC

DRAIN

, CH3:

LED

, CH4: I

LED

Figure 20. Input Voltage: 220VAC, Input Frequency:

64Hz

H1: V

Figure 22. Input Voltage: 265V

, CH2: V

CC

DRAIN

, CH3: V

AC

LED

, CH4: I

LED

, Input Frequency:

64Hz

Table 2. Output Characteristics by Input Voltage & Frequency

90VAC 110VAC 180VAC 220VAC 265VAC

47Hz 64Hz

V

LED(RMS)

27.91V 84.45mA 27.90V 84.58mA

27.99V 84.41mA 28.02V 84.49mA

28.13V 84.94mA 28.10V 84.86mA

28.12V 85.66mA 28.14V 85.77mA

28.17V 87.05mA 28.13V 87.05mA

I

LED(RMS)

V

LED(RMS)

I

LED(RMS)

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 beca use the HV pin is discon nected.

Figure 23. Open-Load Condition Test

CH1: VCC, CH2: V

Figure 24. Test Results of Open-Load Condition

DRAIN

, CH3: V

LED

, CH4: I

LED

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: V

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 26. Test Results of Inductor Short Condition

9. Performance of Evaluation Board

[%] [V]

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 265V

100

95

90

85

80

condition.

AC

75

70

PF_47Hz

PF_64Hz

65

60

55

50

90 110 180 220 264

Figure 27. Power Factor

Table 3. PF Test Results

Input Voltage Power Factor

90VAC

110VAC

180VAC

220VAC

265VAC

47Hz 96.31 64Hz 97.34 47Hz 96.72 64Hz 96.89 47Hz 94.41 64Hz 93.74 47Hz 92.49 64Hz 91.09 47Hz 89.71 64Hz 86.56

9.2. System Efficiency

[%] [V]

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

75

70

65

60

55

50

90 110 180 220 264

Figure 28. System Efficiency

Efficiency_47Hz

Efficiency_64Hz

Table 4. Efficiency Test Results

Input Voltage Frequency Efficiency (%)

90VAC

110VAC

180VAC

220VAC

265VAC

47Hz 83.56 64Hz 83.83 47Hz 83.36 64Hz 83.46 47Hz 80.04 64Hz 80.06 47Hz 77.68 64Hz 77.69 47Hz 75.11 64Hz 75.22

9.3. THD Performance

[V]

[%]

Figure 29 shows the THD performance at different input frequencies. Test results are quite similar, except the 90V (under 30%).

30

25

20

condition, but meets international regulations

AC

15

10

5

0

90 110 180 220 264

Figure 29. THD Performance

Table 5. THD Test Results

Input Voltage Frequency THD (%)

90VAC

110VAC

180VAC

220VAC

265VAC

47Hz 20.99 64Hz 21.82 47Hz 22.26 64Hz 22.46 47Hz 24.96 64Hz 25.31 47Hz 25.50 64Hz 25.84 47Hz 25.75 64Hz 26.72

THD_47Hz

THD_64Hz

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 220V

Figure 30. Thermal Test Result, Bottom-Side

Temperature at 90V

Condition (IC)

AC

input condition.

AC

Figure 31. Thermal Test Result, Top-Side Temperature

at 90VAC Condition (Inductor)

Figure 32. Thermal Test Result, Bottom-Side

Temperature at 110V

Condition (IC)

AC

Figure 33. Thermal Test Result, Top-Side Temperature

at 110VAC Condition (Inductor)

Figure 34. Thermal Test Result, Bottom-Side

Temperature at 220V

Condition (IC)

AC

Figure 36. Thermal Test Result, Bottom-Side

Temperature at 264V

Condition (IC)

AC

Table 6. Temperature performance by Input voltage

Figure 35. Thermal Test Result, Top-Side Temperature

at 220VAC Condition (Inductor)

Figure 37. Thermal Test Result, Top-Side Temperature

at 264VAC Condition (Inductor)

Input Voltage T

T

IC

T

MOSFET

INDUCTOR

90VAC 47.6°C 46.2°C 47.8°C 110VAC 51.4°C 46.9°C 47.8°C 220VAC 66.5°C 55.0°C 54.6°C 265VAC 71.5°C 59.5°C 57.7°C

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, Conducted Emission-Line at 110V

Full Load (10-LED Series)

Figure 39. EMI Test Results, Conducted Emission-Neutral at 110V

Full Load (10-LED Series)

Input Condition,

AC

Input Condition,

AC

Figure 40. EMI Test Results, Conducted Emission-Neutral at 220V

Full Load (10-LED Series)

Input Condition,

AC

Figure 41. EMI Test Results, Conducted Emission-Neutral at 220VAC Input Condition,

Full Load (10-LED Series)

10. Revision History

Rev. Date Description

0.0.1 2011.11.16 First issue

1.0.1 2011.11.30 Update IC temperature

1.0.2 2012.2.20

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.

This board is intended to be used by certified professionals, in a lab environment, following proper safety procedures. Use at your own risk. The Evaluation board (or kit) is for demonstration purposes only and neither the Board nor this User’s Guide constitute a sales contract or create any kind of warranty, whether express or implied, as to the applications or products involved. Fairchild warrantees that its products meet Fairchild’s published specifications, but does not guarantee that its products work in any specific application. Fairchild reserves the right to make changes without notice to any products described herein to improve reliability, function, or design. Either the applicable sales contract signed by Fairchild and Buyer or, if no contract exists, Fairchild’s standard Terms and Conditions on the back of Fairchild invoices, govern the terms of sale of the products described herein.

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Modified, edited, formatted document. Changed User Guide number from FEB_L030 to FEBFL7701_L30U003A

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