Fairchild RD-268 Schematics

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Reference Design RD-268

PFC+PWM Combination Controller FAN4800A, Fairchild Power Switch, FPS™ FSBH0370 and Supervisor IC SG 6520 - 300W Design (80 Plus)

Featured Device Application

FAN4800A FSBH0370

SG6520

ATX PC Power 85~265V

Input Voltage

Range

AC

Output Voltage

(Rated Current)

12V1 (6A)

12V2 (10.5A)

5V (9A)

3.3V (13.5A)

-12V (0.3A) 5V

SB

(2A)

Key Features

FAN4800A

 Pin-to-Pin Compatible with ML4800, FAN4800 , CM6800, and CM6800A  PWM Configurable for Current-Mode or Feedforward Voltage-Mode Operation  Internally Synchronized Leading-Edge PFC and Trailing-Edge PWM in One IC  Low Opera ting Current  Innovative Switching-Charge Multiplier Divider  Average-Current Mode for Input-Current Shaping  PFC Over-Voltage, Under-Voltage, and Feedback Open-Loop Protection  Cycle-by-Cycle Current Limiting for PWM  Power-On Sequence Control and Soft-Start  Brownout Protection

Rated Output

Power

300W

Topology

CCM Boost PFC

+ Two Switch

Forward +

Flyback

FSBH0370

 Internal Avalanche-Rugged SenseFET (700V) in TO220 Package  Constant Power Limit  Advanced Burst-Mode Operation and Green-Mode Function for Low Standby Power Consumption  Internal High Voltage Startup Circuit  Various Protection Functions: Over-Voltage Protection (OVP), Overload Protection (OLP), Internal

Thermal Shut down Functi on (TSD), Brownout Protection

 Built-in Slope Compensation  Built-in Soft-Start: 5ms

SG6520

 Two 12V Sense Input Pins: VS12 and VS12B  Over-Voltage Protection (OVP), Over-Current Protection (OCP), and Under-Voltage Protection (UVP) for

3.3V, 5V, and Two 12V

 Open-Drain Output for PGO and FPO Pins  300ms Power Good Delay  300ms Turn-on Delay for 3.3V, 5V, and Two 12V  2.8ms PSON Control to FPO Turn-off Delay and 48ms PSON Control Delay  No Lockup During the Fast AC Power On/Off  Wide Supply Voltage Range: 4.2V to 15V  Programmable Over-Temperature Protection (OTP)

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1. Schematics

Figure 1. Schematic of Auxiliary Power (FSBH0X70) and Supervisory IC (SG6515/20)

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Figure 2. Schematic of Main Power Stage (FAN4800A)

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2. Flyback Converter Transformer (TX1)

Figure 3. Transformer Schematic Diagram

2.1. Winding Specification

No Pin (S- F) Wire Turns Winding Method

N1/2

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

N2 10Æ8 0.55Ф*2 11Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

N1/2 2Æ1 0.27Ф*4 58Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

N3 5Æ6 0.15Ф 31Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

Core: EEL19 Bobbin: EEL19

3Æ2 0.27Ф 90Ts Solenoid Winding

2.2. Electrical Characteristics

Pin Specification Remark

Primary-Side Inductance

2－3

1.25mH ± 5% 100kHz, 1V

Mylar® is a registered trademark of Dupont Tejin Films

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3. Gate Drive Pulse Transformer (TX2)

Figure 4. Transformer Schematic Diagram

3.1. Winding Specification

No Pin (S - F) Wire Turns Winding Method

N

1

Insulation: Mylar® Tape t = 0.025mm, 3 Layer

N2 9Æ10 0.2Ф 18Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.025mm, 1 Layer

N

6Æ7 0.2Ф 18Ts Solenoid Winding

3

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

Core: ERL35 Bobbin: ERL35

5Æ3 0.2Ф 15Ts Solenoid Winding

3.2. Electrical Characteristics

Pin Specification Remark

Primary-Side Inductance

5－3

210

μH ± 5%

100kHz, 1V

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4. Forward Converter Transformer (TX3)

Figure 5. Transformer Schematic Diagram

4.1. Winding Specification

No Pin (S - F) Wire Turns Winding Method

N

1

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

N2 8,9-10,11,12

Insulation: Mylar® Tape t = 0.03mm, 1 Layer

N3 13-8,9 1.0Ф*4 4Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.03mm, 1 Layer

N4 10,11,12-14 0.4Ф 6Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.03mm, 1 Layer

N5 2-6,7 0.6Ф 37Ts Solenoid Winding

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

Core-ERL35

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

Insulation: Copper-Foil Tape t = 0.05mm-Pin 1 Open Loop

Insulation: Mylar® Tape t = 0.03mm, 3 Layer

Core: ERL35 Bobbin: ERL35

3-2 0.6Ф 37Ts Solenoid Winding

Copper-Foil

10mil

3Ts

Copper-Foil

Width 18mm

4.2. Electrical Characteristics

Pin Specification Remark

Primary-Side Inductance

2－3

13m

μH ± 5%

100kHz, 1V

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5. Boost Inductor (L2)

5.1. Winding Specification

No Pin (S - F) Wire Turns Winding Method

N

1

Core: Toroid core (CM270060)

5.2. Electrical Characteristics

Pin Specification Remark

1Æ2 0.8Ф 117Ts

Primary-Side Inductance

1－2

900

6. Forward Output Inductor (L7)

Figure 6. Inductor Schematic Diagram

6.1. Winding Specification

No Pin (S - F) Wire Turns Winding Method

N1 3Æ8 1.0Ф 24.5Ts

N2 4Æ7 1.0Ф 24.5Ts

N3 1Æ10 1.0Ф 10.5Ts

N4 2Æ9 1.0Ф 10.5Ts

N5 5Æ6 0.5Ф 23.5Ts

Core: Toroid Optimag Magnetic HF106060-2

μH ± 5%

1kHz, 1V

6.2. Electrical Characteristics

Pin Specification Remark

Primary-Side Inductance

3－8

μH ± 5%

40

1kHz, 1V

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7. Typical Performance

Table 1. Standby Power Consumption

Operating Condition Input Power

86

When VIN = 115VAC, with 0.5W Loading 0.785W

When VIN = 230VAC, with 0.5W Loading 0.913W

When VIN = 240VAC, with 0.5W Loading 0.926W

When VIN = 264VAC, with 0.5W Loading 0.958W

85

84

83

82

Efficiency(%)

81

80

79

0 102030405060708090100

115Vac

230Vac

83.49

82.04

85.3

83.39

OutputPower(%)

Figure 7. Efficiency

82.62

80.2

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8. Related Resources

FAN4800A — PFC/PWM Controller Combination Datasheet FSBH0370 — Green Mode Power Switch (FPS™) Datasheet SG6520 — PC Power Supply Supervisors Datasheet AN-8027 — FAN480X PFC+PWM Combination Controller Application

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