Datasheet FEB-L031-1 Datasheet (Fairchild)

User Guide for

FEB-L031-1

Evaluation Board

7.8W LED Ballast at Low Line

Featured Fairchild Product:

FL7701

Direct questions or comments

about this evaluation board to:

“Worldwide Direct Support”

Fairchild Semiconductor.com

Table of Contents

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

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

1.2. Features ............................................................................................................................ 3

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

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

3. Photographs............................................................................................................................... 6

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

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

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

7. Inductor Design ....................................................................................................................... 10

8. Performance of Evaluation Board ........................................................................................... 11

8.1. Typical Waveforms: Startup .......................................................................................... 12

8.2. Operating Frequency & Minimum Duty ........................................................................ 13

8.3. Typical Waveforms: Steady State .................................................................................. 14

8.4. Typical Operating Waveforms: Output Characteristics ................................................. 15

8.5. Typical Waveforms: Abnormal Mode (LED-Open) ...................................................... 16

8.6. Typical Waveforms: Abnormal Mode (Inductor Short) ................................................ 17

8.7. System Efficiency .......................................................................................................... 18

8.8. Power Factor at Rated Load Condition .......................................................................... 19

8.9. Total Harmonic Distortion Performance ....................................................................... 20

8.10. Thermal Performance ..................................................................................................... 21

8.11. Electromagnetic Interference (EMI) Test Results ......................................................... 23

9. 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 low line input, 7.8W LED ballast using the FL7701. The input voltage range is 90V output with a constant current of 250mA at 31V. This document contains general 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 and integrated switching MOSFET. The special “adopted digital” technique automatically detects input voltage condition and sends an internal reference signal, resulting in high power factor (PF). When AC input voltage is applied to the IC, PFC function is automatically enabled. When DC input voltage is applied to the IC, PFC function is automatically disabled. The FL7701 does not require a bulk capacitor (electrolytic capacitor) for supply rail stability, which can significantly improve LED reliability.

– 150V

RMS

.

and there is one DC

RMS

1.2. Features

 Digitally Implemented Active PFC Function

(No Additional Circuit Necessary for High PF)

 Built-in HV Supplying Circuit: Self Biasing  AOCP Function with Auto-Restart Mode  Built-in Over-Temperature Protection (OTP)  Cycle-by-Cycle Current Limit  Low Operating Current: 0.85mA (Typical)  Under-Voltage Lockout with 5V Hysteresis  Programmable Oscillation Frequency  Programmable LED Current  Analog Dimming Function  Soft-Start Function  Precise Internal Reference: ±3%

1.3. Internal Block Diagram

Figure 1. Block Diagram

Pin No. Symbol Description

1

2

3

4

5

6

7

8

CS Current Sense. Limits output current depending on the sensing resistor voltage

OUT OUT. Connects to the MOSFET gate. VCC

RT

ADIM

GND GROUND. Ground for the IC.

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

VCC. Supply pin for stable IC operation and IC uses this pin for catching ZCD

signal to make internal artificial reference.

RT. Programmable operating frequency using external resistor and IC has fixed frequency even though this pin open or floating.

Analog Dimming. Connect to the internal current source. Can change output

current using external resistor. Connect small capacitor at non-dimming condition.

No Connection.

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 Minimum Input Voltage

Input Voltage

Range

AC Input Frequency

Output Voltage

Output Current

Output Power

(1)

(2)

IN.MIN

V

IN.NORMAL

V

Freq

V

OUT,MAX

V

OUT,NORMAL

V

I

OUT.NORMAL

CC Deviation < ±1.6%

110V Normal Input Voltage

150V Maximum Input voltage

IN.MAX

47Hz Minimum Input Frequency

IN.MIN

64Hz Maximum Input Frequency

IN.MAX

33V Maximum Output Voltage

31V Normal Output Voltage

29V Minimum Output Voltage

OUT,MIN

250mA Normal Output Current

Line Input Voltage Change:

Output Power 7.8W

90~150VAC

Efficiency

Temperature

PCB Size

Initial Application

> 82% At Full Load

T

< 56°C

FL7701

T

< 67°C

DM filter

T

FRD,ES3J

T

MOSFET

T

inductor

< 53°C

< 58°C

< 46°C

At full load (all at open-frame, room

temperature / still air)

28mm (width) x 52mm (length )x

20mm (height)

LED Bulb

Notes:

1. The output current has I

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

LEDPK

in 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.

3. Photographs

Figure 2. Top-View (28mm x 52mm)

Figure 3. Bottom-View (28mm x 52mm)

Figure 4. Side-View (20mm)

4. Printed Circuit Board

Figure 5. Top Side

Figure 6. Bottom Side

5. Schematic

Figure 7. Schematic

6. Bill of Materials

Item

No.

1 Fuse SS-5-1A 1 1A / 250VAC Bussmann

2 U1 FL7701M 1 Controller

3 BD MB6S 1 0.5A / 600V, Bridge Diode

4 C1 MPE 630V223K 1 22nF / 630VAC, Film Capacitor Sungho

5 C2 MPE 400V104K 1 100nF / 400VAC, Film Capacitor Sungho

6 C3

7 C4 C1206C105K3PACTU 1

8 C5 C1206C102JBGACTU 1

9 Q1 FQD1N60C 1

10 D1 ES3J 1 3A / 600V, Ultra-Fast Recovery

11 D2 1N4148 1 0.2A / 200V Small Signal Diode

12 L1 RFB0810-153L 1 15mH, Filter Inductor Coilcraft

13 L2 R06682KT00 1 6.8mH, Filter Inductor Bosung

14 R1 RC1206JR-07561RL 1 560Ω, SMD Resistor 3216 Yageo

15 R2 0 Open

16 R3 RC1206JR-072R4RL 1 2.4Ω, SMD Resistor 3216 Yageo

17 R4 RC1206JR-072R2RL 1 2.2Ω, SMD Resistor 3216 Yageo

Part

Reference

Part Number Qty. Description Manufacturer

Fairchild

Semiconductor

Fairchild

Semiconductor

C0805C101K3RACTU

1

100pF / 25V SMD Capacitor

2012

1µF / 25V SMD Capacitor 3216

1nF / 630V SMD Capacitor

3216

1A / 600V D-PAK

Kemet

Fairchild

Semiconductor

Fairchild

Semiconductor

Fairchild

Semiconductor

18 R5

19 R6 0 Open

RC0805JR-07101RL

1 100Ω, SMD Resistor 2012 Yageo

7. Inductor Design

 Follow Safe Standard  Inductor Core: EE1614 (TDK)  N1: 280 Turns  Inductance Value (1  6): 5.5mH

Table 2. Inductor Specification

No. Winding Pin (S  F) Wire Turns Winding Method

1 N1 1  6 0.2Ø 280Ts Solenoid Winding

2 Insulation: Polyester Tape t = 0.025mm 3-Layer

8. Performance of Evaluation Board

Table 3. Test Condition & Equipments

Test Temperature

Test Equipment

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 (1W) by Everlight

TA = 25°C

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.

Figure 8. Soft-Start, AC Mode, 90VAC

CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 9. Soft-Start, AC Mode, 150V

CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

AC

, CH4: I

LED

Figure 10. Soft-Start, DC Mode, 100VDC

CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

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

CH1: VCC, CH2: V

DRAIN

, CH3: V

LED

, CH4: I

DC

LED

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.

Switching Frequency: 44.18kHz

CH1: V

Figure 12. Operating Frequency & Minimum Duty Ratio

, CH2: V

CC

DRAIN

, CH3: V

Minimum On-Time: 4.03µs

LED

, CH4: I

LED

8.3. Typical Waveforms: Steady State

V

Figure 13 through Figure 20 show the normal operation waveform by input voltage and input frequency. The output voltage and current maintains a certain output level with 120Hz ripple, as shown in the test results in Table 4.

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

47Hz, CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

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

64Hz, CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 15. Input Voltage: 110VAC, Input Frequency:

47Hz, H1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 16. Input

64Hz, H1: V

oltage: 110VAC, Input Frequency:

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

8.4. Typical Operating Waveforms: Output Characteristics

V

Figure 17. Input Voltage: 130VAC, Input Frequency:

47Hz, CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

Figure 18. Input

LED

64Hz, CH1: V

oltage: 130VAC, Input Frequency:

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

Figure 19. Input Voltage: 150

47Hz, CH1: V

, CH2: V

CC

DRAIN

Table 4. Output Characteristics by Input Voltage and Frequency

90VAC 110VAC 130VAC 150VAC

, Input Frequency:

AC

, CH3: V

LED

V

LED(RMS)

, CH4: I

31.11V 247.7mA 31.10V 247.9mA

31.42V 251.0mA 31.41V 251.3mA

31.57V 251.6mA 31.56V 251.7mA

31.64V 251.6mA 31.69V 251.8mA

Figure 20. Inp ut Vo ltage: 150VAC, Input Frequency:

LED

64Hz, CH1: V

, CH2: V

CC

DRAIN

, CH3: V

LED

, CH4: I

LED

47Hz 64Hz

I

LED(RMS)

V

LED(RMS)

I

LED(RMS)

8.5. Typical Waveforms: Abnormal Mode (LED-Open)

Figure 21 and Figure 22 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.

C5

1nF

OPEN

Fuse

1A/250V

AC Input

BD

MS6S

L1

C1

22nF

15mH

R1

560R

R2

OPEN

L2

6.8mH

C2

100nF

2.4

FQD1N60C

R3

D1

ES3J

1N4148

Q1

R5

100

R4

2.2 C4

1µF

D2

(Series 10-LEDs)

1

2

3

4

R6

OPEN

Figure 21. Open-Load Condition Test

LED

CS

OUT

VCC

RT

HV

NC

GND

ADIM

8

7

6

5

C3

100pF

L3

5.5mH

CH1: VCC, CH2: V

Figure 22. Test Results of Open-Load Condition

DRAIN

, CH3: V

LED

, CH4: I

LED

8.6. Typical Waveforms: Abnormal Mode (Inductor Short)

Figure 23 and Figure 24 show the test method and result of an inductor short. The FL7701 uses an abnormal over-current protection (AOCP) function, limiting the current on RCS in the event of an inductor short.

FL7701

Figure 23. Inductor-Short Condition

When CS pin voltage reaches

2.5V, AOCP is enabled after 70ns internal delay time

CH1: VCS, CH2: V

Figure 24. Test Results of Inductor Short Condition

DRAIN

, CH3: V

LED

, CH4: I

LED

8.7. System Efficiency

Figure 25 shows system efficiency results for different AC input voltage frequency conditions. As shown, the input frequency has negligible effect on system efficiency.

Efficiency

Figure 25. System Efficiency

VIN

Table 5. System Efficiency Test Result

Input Voltage Efficiency (%)

90VAC

110VAC

130VAC

150VAC

47Hz 82.97

64Hz 82.81

47Hz 84..87

64Hz 84.88

47Hz 86.04

64Hz 86.08

47Hz 86.50

64Hz 86.61

8.8. Power Factor at Rated Load Condition

Figure 26 shows the system Power Factor (PF) performance for the entire input voltage range (90V changes slightly according to the input frequency.

PF

to 150VAC) at different input frequency conditions (47Hz, 64Hz). The PF

AC

VIN

Figure 26. Power Factor

Table 6. Power Factor Test Results

Input Voltage (V

90VAC

110VAC

130VAC

150VAC

) Frequency (Hz) PF

AC

47Hz 0.97

64Hz 0.97

47Hz 0.97

64Hz 0.97

47Hz 0.97

64Hz 0.97

47Hz 0.96

64Hz 0.96

8.9. Total Harmonic Distortion Performance

Figure 27 shows the Total Harmonic Distortion (THD) performance at different input frequencies. Test results meet international regulations (under 30%).

THD

VIN

Figure 27. Total Harmonic Distortion Performance

Table 7. Total Harmonic Distortion Test Results

Input Voltage (V

90VAC

110VAC

130VAC

150VAC

) Frequency (Hz) THD (%)

AC

47Hz 23.60

64Hz 23.39

47Hz 23.45

64Hz 23.17

47Hz 24.92

64Hz 24.90

47Hz 26.40

64Hz 26.46

8.10. Thermal Performance

V

Figure 28 through Figure 35 show the steady-state thermal test results with different input voltage conditions. Filter inductor L2 has the highest temperature on the top side of the PCB due to copper resistance. The switching MOSFET has the highest temperature on the bottom side of the PCB. The IC temperature is 56.4°C for 150V

input condition.

AC

MOSFET (Q1):

58.3℃

Diode (D1):

53.4℃

IC TEMP:

51.6℃

Inductor TEMP:

45.5℃

Filter L2 TEMP:

67.4℃

Figure 28. Bottom-Side Temperature at 90V

Condition (IC)

MOSFET (Q1):

57.0℃

IC TEMP:

52.9℃

AC

Figure 29. Top-Side Temperature at 90V

(Inductor)

Filter L2 TEMP:

57.7℃

Condition

AC

Inductor TEMP:

Diode (D1):

52.4℃

45.7℃

Figure 30. Bottom-Side Temperature at 110

Condition (IC)

Figure 31. Top-Side Temperature at 110V

AC

(Inductor)

Condition

AC

V

MOSFET (Q1):

56.3℃

IC TEMP:

54.4℃

Diode (D1):

51.9℃

Figure 32. Bottom-Side Temperature at 130

Condition (IC)

MOSFET (Q1):

56.7℃

IC TEMP:

56.4℃

Filter L2 TEMP:

51.7℃

Inductor TEMP:

45.8℃

Figure 33. Top-Side Temperature at 130V

AC

(Inductor)

Filter L2 TEMP:

48.3℃

Condition

AC

Diode (D1):

52.5℃

Figure 34. Bottom-Side Temperature at 150

Condition (IC)

Table 8. Temperature Performance by Input Voltage

Input Voltage (V

90VAC 51.6°C 58.3°C 67.4°C

110VAC 52.9°C 57.0°C 57.7°C

130VAC 54.4°C 56.3°C 51.7°C

150VAC 56.4°C 56.7°C 48.3°C

AC

) TIC

Inductor TEMP:

45.9℃

Figure 35. Top-Side Temperature at 150

(Inductor)

T

MOSFET

Condition

AC

T

FILTER L2

8.11. Electromagnetic Interference (EMI) Test Results

EMI test measurements were conducted in observance of CISPR22 criteria, which has stricter limits than CISPR15 for lighting applications.

Figure 36. Conducted Emission - Line at 110VAC Input Condition, Full Load (10-LED Series)

Figure 37. Conducted Emission - Neutral at 110VAC Input Condition, Full Load (10-LED Series)

9. Revision History

Rev. Date Description

1.0.0 July 2012 First Release

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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