fps design guide - mouser electronics · 5 fps™ design guide when you plug into a power...

Fairchild’s Power Switch For Switch Mode Power Supply

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Building Block Solutions for Multi-Market Applications

FPSTM

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www.fairchildsemi.com/fps

FPS™ Design Guide

What is Fairchild Power Switch FPS™ .......................................................................................................5

FPS™ Integrated Solution .........................................................................................................................6

Green FPS™ – New FPS™ Family.............................................................................................................7

Green FPS™ Features and Advantages......................................................................................................8

Burst Mode Operation .......................................................................................................................9

Frequency Modulation for EMI ..........................................................................................................10

Over Load Protection .......................................................................................................................11

FPS™ Core Products ..............................................................................................................................12

Complete FPS™ Product Offering Sorted by Output Power.........................................................................13

Typical Applications ..............................................................................................................................14

Examples of Typical Application Circuits .............................................................................................15-26

1W Power Supply with Less Than 100mW Standby Power ..................................................................15

Dual Negative Output Non-Isolated Flyback .......................................................................................16

2.5W Single Output Isolated Flyback Using FSD200 with KA431 Reference .........................................17

10W Single Output Isolated Flyback Using FSDM0265R and Zener Diode ...........................................18

10W Multiple Output Isolated Flyback Using FSD210 with Primary Side Regulation ...............................19

5W Buck Converter Using FSDL0165RN ...........................................................................................20

16W Multiple Output Isolated Flyback Converter Using FSDM0265RN.................................................21

180W–200W KA5Q1265RF Quasi-resonant Flyback with Input Power

Factor Correction Using FAN7527B/FQP13N50C.........................................................................22-23

40W Isolated Flyback Power Supply .................................................................................................24

24W Single Output 48V DC/DC Flyback Converter ...........................................................................25

Secondary Side Synchronous Rectification in a Power Over Ethernet Application ...................................26

Design Tools .........................................................................................................................................27

Ordering Guide ....................................................................................................................................28

Table Of Contents

5


FPS™ Design Guide

When you plug into a power receptacle anywhere in the world, more than likely the plug you are holding linksyou to an off-line AC to DC power converter. The heart of today’s off-line converter is an integrated circuit (IC)that not only contains the Pulse Width Modulation (PWM) circuitry and a power MOSFET converter that isrequired for efficient conversion from AC to DC but also integrates a myriad of control and protection circuitrythat makes yesterday’s off-line converters bulky by comparison. Fairchild Power Switch (FPS™) is a family ofproducts that combines the avalanche rugged power SenseFET with state-of-the-art PWM circuitry to address avariety of Switch Mode Power Supplies (SMPS).

An FPS™ IC contains protection against excessive heating within the converter, overloading of any DC output,excessive currents that could damage the power MOSFET and excessive voltage of controlled DC output. Thesenecessary protection features are combined with advanced control features such as burst mode operation forlow standby power, a precision oscillator with frequency modulation to minimize EMI, and soft start.

Fairchild offers two design approaches:1) Parallel dice, with SenseFET and PWM die side-by-side in one package,2) Single die, monolithic design

The choice of these approaches allow cost-effective designs for a broad range of applications that includechargers, adapters, set top boxes, VCR, DVD players, LCD and CRT TVs, LCD and CRT monitors, white goods,PCs, notebooks and assorted household appliances.

The integration level is optimal and minimizes component count and saves board space. The FPS™ concept provides cost-effective solutions for Flyback and Forward Converter topologies with outstanding reliability.

Combined with years of manufacturing expertise, these state-of-the-art off-line power switching solutions providethe designers with the ability to do rapid production ramp-ups of their advanced SMPS design.

What is Fairchild Power Switch (FPS™)

6


FPS™ Design Guide

Optimally Integrated Solution for Off-Line Switch Mode Power Supplies

• Integrated features in a single package

– SenseFET

– PWM controller

– Gate drive circuit

– Precise frequency oscillator

• Additional functions

– Startup circuit with soft start

– Frequency modulation

– Burst operation

• Protection function

– Over load protection

– Over voltage protection

– Over current protection

– Pulse by pulse current limit

– Over temperature protection

+

–~ ~

ACInput

Vo

Softstart

FrequencySetting

CurrentSensing

MOSFETDrive

PWMController

StartupResistor

MOSFET

UC3842

Comp Vref

RtCt

Isense

Vfb Vcc

Out

GND

FPS™ Integrated Solution

7


FPS™ Design Guide

Green FPS™ – New FPS™ Family

Green FPS™ is a New Family of FPS™ Products:• Used in low standby power applications that meet the less than

1 Watt standards (i.e. EnergyStar)

• Supports environmentally friendly systems

• Integrated solution of multiple protection and control features built with the powerswitch MOSFET available in a very small package

Output Power GreenFPS™ Additional Features Application ExampleLevel Part Number

Low Power FSD200 Self biasing (FSD200) Charger

FSD210 Frequency modulation Auxiliary supply (for small display or controller

FSDM311 Burst mode boards in white goods for example)

FSDL312 Built-in startup

Soft start

Medium Power FSD1000 Auxiliary supplies PC main supply and PC auxiliary supply

(FPS with main power PWM integrated) Burst mode

Programmable soft start

Internal startup

FSDL0165RN Frequency modulation DVD player and auxiliary supply

FSDH0265RN Built-in startup DVD player

FSDM0265RN Soft start Digital Still Camera (DSC)

FSDL0365RN Burst mode DVD R/W

FSDM0365RN Programmable current limit LCD monitor

Digital Still Camera (DSC)

Set top box

FSDM0565R Bulit-in startup LCD monitor

FSDM07652R Soft start Notebook adapter

Burst mode Set top box

High Power FSCQ0765RT* Burst mode Color TV

FSCQ15658RT* Reducing IC current DVD receiver

Maximum frequency limit Plasma display panel

Soft start with fast settling

* Product in development

8


FPS™ Design Guide

Simplified Application Circuit for FPS™ Features

• Optimal Solution for Off-Line SMPS

• Integrated Avalanche Rugged SenseFET

• Pulse-by-Pulse Current Limiting

• Various Protection Functions (Over Voltage, Over Load, OverCurrent, Thermal Shutdown)

• Burst Mode Operation for LowStandby Power

• Frequency Modulation for Reduced EMI

• Soft Start Function

• Operation Frequency Options(50/70/100/134kHz)

• External Frequency Synchronization

• Quasi Resonant

SnubberCircuit

Load

+

+ ++

FeedbackCircuitControl

IC

FPS™

Advantages• Low Standby Consumption with Burst Mode Operation

• Fully Avalanche Rugged, 650V and 800V SenseFETs Improves Reliability

• Reduced EMI with Fully Integrated Frequency Modulation

• Reduces the Total Bill-of-Materials Cost with Integrated Protection and Control Functions

• Broad Application Coverage with Extensive Expertise and Easy-to-Use Design Tools

Green FPS™ Features and Advantages

FPS™ Parallel Dice Solution (Side- by- Side)

GNDVccIpk FB

DrainDrainVstr Drain

SenseFETPWMIC

FPS™ Single Die Solution (BCDMOS)

GNDGNDVFB GND

VstrDrainVcc

9


FPS™ Design Guide

Green FPS™ Feature – Burst Mode Operation

Current Waveform

FeedbackWaveform

Burst Operation

Normal Operation

Not Switching

Not Switching

VBURSTH

VBURSTL

(Refer to schematic in Typical Application Circuit 40W Isolated Flyback Power Supply on page 24)

• In standby mode, outputs draw very little to no load current

• Output voltages increase causing the feedback voltage to decrease

• When the feedback voltage goes below VBURSTL threshold, switching stops in the FPS devicesaving considerable power

• Depending on load current, the output voltages will eventually fall causing the feedback voltage to increase

• Once the feedback voltage crosses VBURSTH threshold, switching starts again

• A 5V output FSD210 board at 265V in no load standby consumes a mere 92mW

Below shows the waveforms of both normal and standby modes at the voltage extremes for the universalvoltage range.

standby normalstandby normal

Burst Operation @ 85VAC Burst Operation @ 265VAC

10


FPS™ Design Guide

Green FPS™ Feature – Frequency Modulation for EMI

130kHz

131kHz

132kHz

133kHz

134kHz

135kHz

136kHz

137kHz

138kHz

2mS

A

B

C

130kHz134kHz138kHz

SawtoothWaveform

Ton

Vfb

Vdrain

Idrain

A B C

• Fixed frequency oscillators generate Electromagnetic Interference (EMI) in a narrow band of the frequency spectrum

• Fairchild’s latest FPS devices modulate its frequency over a±4kHz frequency range

• EMI is thus spread over a wider range of frequencies

• Allows simple EMI filters to be employed for meeting worldwide EMI requirements

• Refer to Application Note AN-4145 Electromagnetic Compatibility for Power Converters for additional information

Below shows the frequency spectrum waveforms of a fixed frequency device versus a device that employsfrequency modulation.

100kHz Fixed FrequencyFSDH0165

134kHz with Frequency ModulationFSD210

Peak Level Limit

Peak Level Limit

Peak Waveform

Quasi Peak Waveform

11


FPS™ Design Guide

Green FPS™ Feature – Over Load Protection

ShutdownVSD

V

tt1 t2

Time Constant t2 = (Cfb * (VSD-3V))/5uA

0

3V

OSC.5uA 250uA

2.8R

R

Voffset

S

RQ

Vck

FB

Vfb*

VSD

SQ

R

Vo

Cfb

ThermalShutdown

Reset

Shutdown

Secondary Side

LEB

• Consider the load current increasing significantly in this overload scenario.

• The FPS increases its duty cycle within the limits of its pulse-by-pulse current limit.

• The output voltage falls and the feedback voltage rises in response.

• If it is just a momentary surge, then the output will rise after the surge and the feedback voltage willresume its steady state.

• However, if it is not a surge, for example; if output is shorted to ground, then feedback voltage continues to rise.

• At 3V, the feedback voltage is pulled up with a small internal 5µA current, allowing for adjusting the delayas shown above.

• When the feedback voltage crosses the over load shutdown (VSD) threshold, the FPS stops switching.

• With the FPS not switching, bias current is not supplied to the FPS supply (VCC) storage capacitor.

• When the VCC voltage reaches its "under voltage lock out" threshold, the FPS is automatically restarted.

• The cycle will repeat until the fault is removed, providing a quick recovery from the overload condition tonormal operation.

Below are waveforms showing the over load protection and auto-restart occurring repeatedly for a static faultcondition and a close-up of the feedback voltage showing when the over load protection is triggered andswitching stops.

Over Load Protection andAuto-Restart @ 265VAC

Feedback Over Load Protection Level @ 265VAC

12


FPS™ Design Guide

FPS™ Core Products

Product/Function

FunctionPart Typical Output Power Output Power Peak Current Drain Voltage Static Drain Source Switching Packages Number Applications (85 – 265Vac) (230Vac) ±15% Limit MAX On Resistance MAX Frequency

(W) (W) (A) (V) (Ω) (kHz)

FSD200 Charger 4.8 7.2 0.3 700 32 134 DIP-7L

FSD210 Charger 4.8 7.2 0.3 700 32 134 DIP-7L

FSDM311 PC Aux 7.2 7.2 0.6 650 19 67 DIP-8L

FSD1000 PC 12.0 13.6 Adjustable 700 9 70 DIPH-12L

FSDL0165RN DVDP/STB 12.0 13.6 1.2 650 10 50 DIP-8L

FSDL312 PC Aux 12.0 13.6 1.2 650 10 50 DIP-8L

FSDM0265RN DVDP/STB 16.0 18.4 1.5 650 6 67 DIP-8L

FSDH0265RN DVDP/STB 16.0 18.4 1.5 650 6 100 DIP-8L

FSDL0365RN DVDP/STB 24.0 28.0 2.2 650 4.5 50 DIP-8L

FSDM0365RN DVDP/STB 24.0 28.0 2.2 650 4.5 67 DIP-8L

FSDM0565R LCD Monitor 48.0 56.0 2.3 650 2.2 67 TO-220F-6L

FSDM07652R LCD Monitor 60.0 68.0 2.5 650 1.6 67 TO-220F-6L

FS7M0680 PDP, PC 64.0 80.0 4.0 800 2.0 67 TO-3P-5L

FS7M0880 PDP, PC 88.0 104.0 5.0 800 1.5 67 TO-3P-5L

FS8S0765RCB CRT Monitor 64.0 80.0 4.0 650 1.6 sync TO-220-5L

FS8S0965RCB CRT Monitor 96.0 116.0 6.0 650 1.2 sync TO-220-5L

FS6S1265RE CRT Monitor 128.0 152.0 8.0 650 0.9 sync TO-3P-5L

FS6S1565RB CRT Monitor 160.0 192.0 9.7 650 0.65 sync TO-3P-5L

KA5Q0765RTH C-TV 80.0 104.0 5.0 650 1.6 QRC TO-220F-5L

KA5Q1265RF C-TV 160.0 184.0 8.0 650 0.9 QRC TO-3PF-5L

KA5Q1565RF C-TV 216.0 240.0 11.5 650 0.65 QRC TO-3PF-5L

Control Feature/Protection Mode

Control Feature Protection ModePart Soft Frequency Green FPS™ Bias Feedback Over Load Thermal Over Current Over Voltage Under Volt.Number Start Modulation Family Winding Mode Protection Shutdown Protection Protection Lock Out

FSD200 Internal Soft Start Yes Yes Not Needed Voltage Auto Restart Auto Restart No No No

FSD210 Internal Soft Start Yes Yes Needed Voltage Auto Restart Auto Restart No No Yes

FSDM311 Internal Soft Start No Yes Needed Voltage Auto Restart Auto Restart No Auto Restart Yes

FSD1000 Internal Soft Start No Yes Needed Current/Voltage Auto Restart Auto Restart No Latch Yes

FSDL0165RN Internal Soft Start Yes Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDL312 Internal Soft Start Yes Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDM0265RN Internal Soft Start Yes Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDH0265RN Internal Soft Start Yes Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDL0365RN Internal Soft Start Yes Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDM0365RN Internal Soft Start Yes Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDM0565R Internal Soft Start No Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FSDM07652R Internal Soft Start No Yes Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FS7M0680 Soft Start No No Needed Current Latch Latch Latch Latch Yes

FS7M0880 Soft Start No No Needed Current Latch Latch Latch Latch Yes

FS8S0765RCB Soft Start No No Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FS8S0965RCB Soft Start No No Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FS6S1265RE Soft Start No No Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

FS6S1565RB Soft Start No No Needed Current Auto Restart Auto Restart Auto Restart Auto Restart Yes

KA5Q0765RTH No No No Needed Current Auto Restart Latch Latch Auto Restart Yes

KA5Q1265RF No No No Needed Current Auto Restart Latch Latch Auto Restart Yes

KA5Q1565RF No No No Needed Current Auto Restart Latch Latch Auto Restart Yes

13


FPS™ Design Guide

Complete FPS™ Product Offering Sorted By Output Power

FunctionPart Recommended Typical Output Power Output Power Peak Current Drain Static Drain Source Switching PackagesNumber Replacement Applications (85-265Vac) (230Vac) ±15% Limit Voltage MAX on Resistance Frequency

(W) (W) (A) (V) MAX (Ω)0 to 10W Output Power RangeFSD200 Charger 4.8 7.2 0.3 700 32 134kHz DIP-7LFSD210 Charger 4.8 7.2 0.3 700 32 134kHz DIP-7LFSDH0165D FSDM311 Charger 7.2 7.2 0.5 650 18 100kHz DIPH-8LFSDM311 PC Aux 7.2 7.2 0.6 650 19 67kHz DIP-8LKA5H0165RN FSDL0165RN Charger Aux 8.0 8.0 0.6 650 10 100kHz DIP-8LKA5L0165RN FSDL0165RN Charger Aux 8.0 8.0 0.6 650 10 50kHz DIP-8LKA5M0165RN FSDL0165RN Charger Aux 8.0 8.0 0.6 650 10 67kHz DIP-8L10 to 50W Output Power RangeFSD1000 PC 12.0 13.6 Adjustable 700 9 70kHz DIPH-12LFSDL0165RN DVDP/STB/VCR 12.0 13.6 1.2 650 10 50kHz DIP-8FSDL312 PC Aux Power Supply 12.0 13.6 1.2 650 10 50kHz DIP-8LKA5H0165R FSDH0265RN Charger Aux 12.0 12.0 0.6 650 10 100kHz TO-220F-4LKA5H02659RN FSDH0265RN Aux Power Supply 12.0 13.6 0.9 650 6 100kHz DIP-8LKA5L0165R FSDM0265RN Charger Aux 12.0 12.0 0.6 650 10 50kHz TO-220F-4LKA5M0165R FSDM0265RN Charger Aux 12.0 12.0 0.6 650 10 67kHz TO-220F-4LKA5M02659RN FSDM0265RN Aux Power Supply 12.0 13.6 0.9 650 6 67kHz DIP-8LFSDH0265RN DVDP/STB/VCR 16.0 18.4 1.5 650 6 100kHz DIP-8LFSDM0265RN DVDP/STB/VCR 16.0 18.4 1.5 650 6 67kHz DIP-8LKA5H0265RC FSDM0365RN Aux Power Supply 20.0 24.0 1.2 650 6 100kHz TO-220-5LKA5H0280R DVDP/STB/VCR 20.0 24.0 1.2 800 7 100kHz TO-220F-4LKA5L0265R FSDL0365RN Aux Power 20.0 24.0 1.2 650 6 50kHz TO-220F-4LKA5L0365RN FSDL0365RN DVDP/STB/VCR 20.0 24.0 2.2 650 4.5 50kHz DIP-8LKA5M0265R FSDM0365RN Aux Power Supply 20.0 24.0 1.2 650 6 67kHz TO-220F-4LKA5M0280R DVDP/STB/VCR 20.0 24.0 1.2 800 7 67kHz TO-220F-4LKA5M0365RN FSDM0365RN DVDP/STB/VCR 20.0 24.0 2.2 650 4.5 67kHz DIP-8LFSDL0365RN DVDP/STB/VCR 24.0 28.0 2.2 650 4.5 50kHz DIP-8LFSDM0365RN DVDP/STB/VCR 24.0 28.0 2.2 650 4.5 67kHz DIP-8LKA5H0365R DVDP/STB/VCR 32.0 40.0 2.2 650 4.5 100kHz TO-220F-4LKA5H0380R DVDP/STB/VCR 32.0 40.0 2.2 800 5 100kHz TO-220F-4LKA5L0365R DVDP/STB/VCR 32.0 40.0 2.2 650 4.5 50kHz TO-220F-4LKA5L0380R DVDP/STB/VCR 32.0 40.0 2.2 800 5 50kHz TO-220F-4LKA5M0365R DVDP/STB/VCR 32.0 40.0 2.2 650 4.5 67kHz TO-220F-4LKA5M0380R DVDP/STB/VCR 32.0 40.0 2.2 800 5 67kHz TO-220F-4LFSDM0565R LCD Monitor 48.0 56.0 2.3 650 2.2 67kHz TO-220F-6L50 to 100W Output Power RangeFSDM07652R LCD Monitor 60.0 68.0 2.5 650 1.6 67kHz TO-220F-6LFS6M12653RTC LCD Monitor 64.0 76.0 3.2 650 0.9 70kHz TO-220F-5LKA5M0765RQC FSDM07652R LCD Monitor 80.0 96.0 5.0 650 1.6 67kHz TO-220-5LFS7M0680 Plasma Display, PC 64.0 80.0 4.0 800 2.0 67kHz TO-3P-5LKA5P0680C PC 64.0 80.0 4.0 800 2 Adjustable TO-220-5LFS7M0880 Plasma Display, PC 88.0 104.0 5.0 800 1.5 67kHz TO-3P-5LKA5M0965Q LCD Monitor 96.0 116.0 6.0 650 1.2 67kHz TO-3P-5L60-160W Output Power RangeFS6S0765RCH FS8S0765RCB CRT Monitor 64.0 80.0 4.0 650 1.6 sync TO-220-5LFS6S0965R FS8S0965RCB CRT Monitor 96.0 116.0 6.0 650 1.2 sync TO-3P-5LFS6S0965RCB FS8S0965RCB CRT Monitor 96.0 116.0 6.0 650 1.2 sync TO-220-5LFS8S0765RCB CRT Monitor 64.0 80.0 4.0 650 1.6 sync TO-220-5LFS8S0965RCB CRT Monitor 96.0 116.0 6.0 650 1.2 sync TO-220-5LFS6S1265RE CRT Monitor 128.0 152.0 8.0 650 0.9 sync TO-3P-5LFS6S1565RB CRT Monitor 160.0 192.0 9.7 650 0.65 sync TO-3P-5L50-220W Output Power RangeKA5Q0565RT C-TV 56.0 64.0 3.5 650 2.2 QRC TO-220F-5LKA5Q0740RT C-TV 80.0 5.0 400 1.1 QRC TO-220F-5LKA5Q0765RTH C-TV 80.0 104.0 5.0 650 1.6 QRC TO-220F-5LKA5Q12656RT C-TV 120.0 144.0 6.0 650 0.9 QRC TO-220F-5LKA5Q1265RF C-TV 160.0 184.0 8.0 650 0.9 QRC TO-3PF-5LKA5Q1565RF C-TV 216.0 240.0 11.5 650 0.65 QRC TO-3PF-5LFSCQ0765RT* C-TV 80.0 104.0 5.0 650 1.6 QRC TO-220F-5LFSCQ15658RT* C-TV 160.0 184.0 8.0 650 0.65 QRC TO-220F-5L48V DC/DC Flyback ConverterFS6X1220RT DC/DC Off-line 3.2 200 0.3 300kHz TO-220F-5LFS6X1220RD* DC/DC Off-line 3.2 200 0.3 300kHz D2-PAK-5L

* In development

14


FPS™ Design Guide

Typical Applications

50-220WOutput Power Range

60-160WOutput Power Range

50–100WOutput Power Range


0–12W Output Power Range

KA5Q0765RTHKA5Q1265RFKA5Q1565RFFSCQ0765RTFSCQ15658RT

FSDM311FSD200FSD210

FSDM311FSDL312FSD1000

FSDM0565RFSDM07652RFSCM0765RDFS7M0680FS7M0880

FS8S0765RCBFS8S0965RCBFS6S1265REFS6S1565RB


FSDL0165RNFSDH0265RNFSDM0365RNFSDM0565RFSDM07652R

15


FPS™ Design Guide

Examples of Typical Application Circuits

85V-265VAC input

Lp = 1200uH 94/9/2 EF13 (on Vogt Fi324 core)

9V/100mA output

fsw=134kHz

12

VC

C5

DR

AIN

7

VS

TR

8G

ND

1

GN

D2

GN

D3

VF

B4

3

1

4

5

6

1234

CONN1B2P3-VH

FS1230V/250mA

R201100R0.125W

R10510R

0.125W

R202470R0.125W

D201

EGP10D

R100

L100

C10010uF400V

C10110uF400V

C1034.7uF63V

C10447uF50V

+

L101

IC1FSD210M

D105

FDLL4148

T1EF13 VOGT 6PIN

+

R101 Q1BC847B

D202BZX84C90.35W

C201220uF25V

+

D103P6KE150APm = 600W

D102UF4007

+

CONN2B4B-XH-A

D1011N4007

This compact non-isolated flyback solution draws less than 100mW standby power over the whole input voltage range. This exampleshows a 9V output system. Here the FSD210 is powered from an auxiliary winding rather than directly from the high voltage bus. For output voltages of 12V and over, the device may be powered directly from the output winding. A low cost Zener diode circuitprovides the regulation reference.

• Less than 100mW standby power– Ideal for applications permanently connected to an AC supply

• Overload protection circuit distinguishes between temporary and permanent overload– Device does not shut down during load surge conditions– Inherent short circuit protection

• Frequency modulation reduces EMI reduction circuitry– Low cost, compact solution possible

Fairchild Devices DescriptionFSD210M Fairchild Power Switch (0.3A/134kHz)P6KE150A Transient Voltage Suppressor (600W/150V)EGP10D Fast Recovery Diode (1A/200V)BZX84C9 Zener Diode (9V)UF4007 Fast Recovery Diode (1A/1000V)1N4007 General Purpose Diode (1A/1000V)FDLL4148 General Purpose Diode (10mA/100V)BC847B General Purpose Transistor

1W Power Supply with Less Than 100mW Standby PowerTypical Application – Small home or factory automation appliances

16


FPS™ Design Guide


85V-265VAC from applianceinput filter stage

Lp = 1500uH 100/11/10 EF13 (on Vogt Fi324 core)

Pin 3: Mains GroundPin 2: -5V/300mAPin 1: -12V/100mA

-5V/300mA, -12V/100mA output

fsw = 134kHz

12

VC

C5

DR

AIN

7

VS

TR

8G

ND

1

GN

D2

GN

D3

VF

B4

3

1

4

5

6

1

2

3

CONN1B2P3-VH

R201100R0.125W

D201EGP10D

R100

L100

C10010uF400V

+

FS1230V/250mA

D1011N4007

C10347nF63V

D211EGP10D

IC1FSD200M

T1EF13 VOGT 6PIN

CONN2B3P-VH

C201220uF25V

+

D106FDLL4148

Q1BC847B

D202BZX84C5V10.35W

R202470R0.125W

L101

C10110uF400V

+

D103P6KE150A

D102UF4007

C1041uF50V

+

C211220uF25V

+

D1001N4007

R101

Dual Negative Output Non-Isolated FlybackTypical Application – Home appliance control board power supply

A dual non-isolated flyback is used to generate voltages which are negative with respect to the neutral power line. This is used inapplications where triacs are driven, such as in household appliances. A Zener diode, a bipolar transistor and a diode allow thenegative voltage to be regulated by the FPS™. The dual input diode helps to protect against line transients.

• Generation of two negative outputs referred to the input line– Useful for applications using triacs

• High switching frequency reduces the required inductance– More compact, lower cost core

• Frequency modulation reduces EMI reduction circuitry– Split 400V input capacitor and input inductor sufficient in most cases

Fairchild Devices DescriptionFSD200M Fairchild Power Switch (0.3A/134kHz)P6KE150A Transient Voltage Suppressor (600W/150V)EGP10D Fast Recovery Diode (1A/200V)BZX84C5V1 Zener Diode (5.1V)UF4007 Fast Recovery Diode (1A/1000V)1N4007 General Purpose Diode (1A/1000V)FDLL4148 General Purpose Diode (10mA/100V)BC847B General Purpose Transistor

17


FPS™ Design Guide


24V/100mA output

Lp=1700uH 100/25 EF20 (on Vogt Fi324 core)

85V-265VAC from applianceinput filter stage

fsw=134kHz

1

4

8

5

1

2 VC

C5

DR

AIN

7

VS

TR

8G

ND

1

GN

D2

GN

D3

VF

B4

12

23

1

1

23

4

FS1230V/250mA

C20633nF50VC104

33nF50V

T1VOGT EF20

D201SB180

R101

C1022.2nF1000V

C300YCAP250V

R2011K0.25W

D1001N4007

C10110uF400V

+

CONN1B2P3-VH

R2021K0.25W

IC1FSD200M

C1031uF50V

+

R2033K

0.25W

R20491K0.25W

CONN2B2P-VH

L100

IC3KA431LZ

IC2H11A817A.W

D102UF4007

D1011N4007

R102100K0.6W

R20511K0.25W

C201100uF50V

+

C10010uF400V

+

L101

In this converter, isolation is provided by the transformer and the H11A817A optocoupler. Output accuracy is improved using theKA431 voltage reference. The values R201, R203, C206, R204 and C104 set the closed loop control parameters and performance.Using a Schottky diode is a cost-effective method of improving efficiency where needed.

• Feedback circuit using KA431 reference and H11A817A optocoupler– More accurate regulation over line, load and temperature than with a Zener diode

• Schottky diode used in output stage– Cost-effective means of improving efficiency

• Integrated soft start function– Prevents power surges during switch-on time

Fairchild Devices DescriptionFSD200M Fairchild Power Switch (0.3A/134kHz)KA431 2.5V Reference (2.5V)H11A817A Transistor OptocouplerSB180 Schottky Diode (1A/80V)UF4007 Fast Recovery Diode (1A/1000V)1N4007 General Purpose Diode (1A/1000V)

2.5W Single Output Isolated Flyback Using FSD200 with KA431 ReferenceTypical Application – Isolated main or standby power supplies for household appliances

18


FPS™ Design Guide


85V-265VAC input

5V/2A output

Lp = 2400uH 114/9/4 EF20 (on Vogt Fi324)

fsw = 70kHz

1

2

8

63

4

1

2

1

23

4

VStr5

Dra

in7

Dra

in8

GN

D1

Vcc2

VFB3

Dra

in6

Ipk

4

1234

C10122uF400V

+

R10310R0.6W

L100

C202220uF50V

+

T1VOGT EF20

CONN101B2P3-VH

R1044.7K0.6W

IC2H11A817A.W

C300Y1

R201120R0.6W

R102100k2W

D1041N4007

D1011N4007

D1021N4007

L101

L2012.7uH

D1061N4148

FS101230V/3A

R101

C1032.2nF1000V

D1031N4007

IC1FSDM0265RN

D202BZX84C3V9

0.5W

C10222uF400V

+

C201220uF50V

+

C1051uF50V

D105UF4007

C104100nF50V

CONN201B4P-VHD201

SB540

10W Single Output Isolated Flyback Using FSDM0265RN and Zener DiodeTypical Application – Power bricks and single-phase frequency inverters

The FSDM0265RN contains a PWM controller and a MOSFET on two different chips. The 650V MOSFET is fully avalanche ratedand tested which leads to increased system reliability. This application shows a cost reduced feedback circuit using a Zener diode.R104 is used to reduce the current limit. Higher power parts in the green FPS™ family have a higher current limit and a lower RDS(on)than the lower power parts. Using a lower RDS(on) part increases the efficiency, particularly at low input voltages. So replacing a lowpower part with a high power part increases the efficiency but also the current limit. If it were not possible to reduce the current limit,the flyback transformer would have to be rated at the higher current limit, making it more expensive.

• FSDM0265RN has a fully avalanche rated MOSFET– Robust performance under transient conditions


• Current limit may be lowered using an external resistor– Increased flexibility in choice of range of FPS™ parts

Fairchild Devices DescriptionFSDM0265RN Fairchild Power Switch (1.5A/70kHz)BZX84C3V9 Zener Diode (3.9V)H11A817A Transistor OptocouplerSB540 Schottky Diode (5A/40V)UF4007 Fast Recovery Diode (1A/1000V)1N4007 General Purpose Diode (1A/1000V)1N4148 General Purpose Diode (10mA/100V)

19


FPS™ Design Guide


Multiple output flyback converters are used in applications where power is supplied to diverse sub-systems such as drives, tuners,audio stages and complex processor and logic circuits. Primary side regulation is used in this circuit to reduce the total cost. For thispower level and above it is more cost effective to use four diodes in a full bridge configuration than a single diode with a largercapacitor. For high current outputs it is recommended to use a Schottky diode on the secondary side.

• Primary side regulation reduces system cost– Cross regulation is good, total regulation worse than with an optocoupler solution

• Frequency modulation approach minimizes EMI circuitry– Common-mode choke can be replaced by a simple dual capacitor, dual low cost inductor circuit

• Overload protection circuit distinguishes between temporary and permanent overload– Device does not shut down during load surge conditions from drive unit– Inherent short circuit protection

Fairchild Devices DescriptionFSD210M Fairchild Power Switch (0.3A/134kHz)BZX84Cxx Zener Diodes (10V, 12V)P6KE200 Transient Voltage Suppressor (600W/200V)SB140 Schottky Diode (1A/40V)1N4935 Fast Recovery Diode (1A/200V)1N4937 Fast Recovery Diode (1A/600V)UF4007 Fast Recovery Diode (1A/1000V)1N4007 General Purpose Diode (1A/1000V)1N4148 General Purpose Diode (10mA/100V)BC546B General Purpose Transistor

10W Multiple Output Isolated Flyback Using FSD210 with Primary Side RegulationTypical Application – Set top boxes, decoders and small DVD players

195V-265VAC input

10W output

Lp = 2200uH EF20 (on Epcos N67 core)

Primary 81 turns

Vcc 7 turns

5V 3 turns

3.3V 2 turns

12V 9 turns

22V 11 turns

VFD 2 turns

fsw = 134kHz

Vcc

5

DR

AIN

7

VS

TR

8G

ND

1

GN

D2

GN

D3

VF

B4

12

12

11

10

9 5

4

6

2

1

7

8

3

D151N4007

L12.2mH0.09A

C14100nF50V

D1712V

C1122nF50V

C9100uF16V

+

D81N4148

C510uF50V

+

D21N4007

L22.2mH0.09A

C74.7uF400V

+

FS1230V/1A

D11N4935

D5BA159

R10120R

D141N4007

D16SB140

C222uF35V

+

D61N4007

L3 FERRITE BEAD

C1510uF16V

+

IC1FSD210M

Q4BC546B

PL3B2P3-VH

C81uF50V

D3P6KE200

C12100uF16V

+

D1210V

0.5W

D91N4148

D712V

C13100uF16V

+

D13SB140

C64.7uF400V

+

D101N4935

C410uF16V

+

TR1

EF20 EPCOS 12Pin

R11560R

R368R

R101

R2100R

C1033nF50V

C3100nF50V

C12.2nF

Y1

R1

100R

D41N4935

0

0

0 0

0

0

0

0

+3.3V/0.5A

+12V/50mA

FL2/VFD

FL1/VFD

+12VA/50mA

+5V/0.5A

-22V/50mA

-12VA/50mA

20


FPS™ Design Guide


Buck converters are ideal in low power applications where a single non-isolated power output is required. The FSDL0165RN buckcircuit was measured to have an excellent efficiency of over 77% for 15V/100mA, 15V/200mA and 15V/300mA levels over theinput voltage range. Buck circuits need a minimum load. This circuit was measured to have a power consumption of less than350mW with a 15V/10mA output load. The low 50kHz switching frequency option helps to keep the switching losses low. Voltageaccuracy was measured to be around ±6% over line, load and temperature for one board. The fully avalanche rated MOSFET provides additional robustness against voltage transients needed in those industrial applications where buck converters are commonlyused. The current mode control simplifies the feedback control circuit which supports both discontinuous and continuous currentmodes. The device's frequency scaling helps to reduce the EMI caused by the switching.

• Buck converter using FSDL0165 has high efficiency and low standby power– Ideal replacement for 50Hz transformer solutions

• FSDL0165RN has a fully avalanche rated MOSFET– Robust performance under transient conditions

• Current mode control maximizes operating flexibility– Low component count for feedback control circuit– Same circuit operates in DCM and CCM

• Current limit may be lowered using an external resistor• Good control of start-up surge

– Internal soft start feature helps• Frequency modulation helps to reduce EMI

– Cost saving in external filter circuit

Fairchild Devices DescriptionFSDL0165RN Fairchild Power Switch (1.2A/50kHz)BZX84C15 Zener Diodes (15V)UF4004 Fast Recovery Diode (1A/400V)BC337-25 General Purpose Transistor

5W Buck Converter Using FSDL0165RNTypical Application – Industrial automation, household appliances, instrumentation

Vout 15V/300mA

Vin 120Vdc-385Vdc

1 2

VStr5

Dra

in7

Dra

in8

GN

D1

Vcc2

VFB3

Dra

in6

ILim

4

12

C2014.7uF50V

+

Q200BC337-25

CONN1B2P3-VH

R205470R0.25W

L210820uH0.3A

C10422nF50V

D102UF4004

D20015V0.5W

R1045K10.25W

D210UF4004

IC1FSDL0165RN

C2114.7uF50V

+

C10122uF400V

+

CONN2B2P-VH

R204100R0.25W

21


FPS™ Design Guide


85V-265VAC input 16W output

Lp = 1000uH EF25 (on Vogt Fi324 core)

Primary 80 turnsVcc 14 turns5V 6 turns3.3V 4 turns6.6V 8 turns12V 14 turns

16

7

8

9

10

5

3

4

VIN3

GN

D1

VOUT2

-~

~ +

VStr5

Dra

in7

Dra

in8

GN

D1

Vcc2

VFB3

Dra

in6

ILim

4

1 2

VIN3

GN

D1

VOUT2

1

23

4

23

1

C11220uF16V

+

R201220R0.6W

T1

C71000uF16V

+

D1031N4148

R110

D12SB360

L356uH

D14SB360

IC4FAN1112D

DF10MBR101

R2055.6K0.6W

R10322R0.6W

C14220uF16V

+

C9100nF63V

R2021K0.6W

IC1FSDM0265RN

C10310uF50V

+

FS1230V/3A

C10210nF1000V

R10210k2W

C1547uF25V

+

CONN1B2P3-VH

D15SB180

C110275V

C2100nF63V

C122200uF16V

+

C10100nF63V

R2032.2K0.6W

L456uHC104

33uF50V

C206100nF100V

IC5FAN1616AS25

T3

C10147uF400V

+

IC2H11A817A

R1052.2k0.6W

C5100nF63V

C162200uF16V

+

IC3KA431LZ

C300250V

R2041.2K0.6W

D13SB330

D102UF4007

0V

0V

0V

0V

0V

0V

0V

0V

0V

0V

0V

0V

0V0V

0V

12V/100mA

6.6V/0.7A

5V/1.2A(incl 2.5V load)

2.5V

3.3V/1.2A(incl 1.2V load)

1.2V

The isolated, multiple output application shown is suited to applications requiring all of the common logic supply voltages: 5V, 3.3V,2.5V and 1.2V. The flyback architecture is easily expandable: two additional outputs at 12V and 6.6V are shown in this application.The design is scalable to higher power levels by changing the size of the FPS™ device and the transformer. The FSDM0265RN usescurrent mode control which provides excellent response to line and load transient conditions. The flexible overload protection candistinguish between a temporary current surge and a longer term overload condition. The over current latch is a current limit whichis active even during the blanking time. This provides additional system robustness against a secondary diode short circuit condition.

• FSDM0265RN has a fully avalanche rated MOSFET with overcurrent latch– Robust performance under transient conditions– Device switches off if there is a secondary diode short


• Current limit may be lowered using an external resistor– Increased flexibility in choice of range of FPS™ parts

Fairchild Devices DescriptionFSDM0265RN Fairchild Power Switch (1.5A/70kHz)FAN1112D Voltage Regulator (1.2V/1A)FAN1616AS25 Voltage Regulator (2.5A/0.5A)H11A817A Transistor OptocouplerKA431 2.5V Reference (2.5V)DF10M Bridge Rectifier

16W Multiple Output Isolated Flyback Converter Using FSDM0265RNTypical Application – Set top boxes, decoders, and small DVD players

Industrial and communications applications using FPGAs and complex logic chips

Fairchild Devices DescriptionSB180 Schottky Diode (1A/80V)SB330 Schottky Diode (3A/30V)SB360 Schottky Diode (3A/60V)UF4007 Fast Recovery Diode (1A/1000V)1N4148 General Purpose Diode (10mA/100V)

22


FPS™ Design Guide


12345 6 7 8

1

3

22

21

20

19

18

14

17

15

13

16

9

7

63

1114

1

2

12

Dra

in1

GN

D2

Vcc

3

FB

4

Syn

c5

123456789

1

23

4

R318470K0.25W

R306

10R0.25W

L24110uH

5A

FAN7527B

L20110uH

5A

C230470pF1000V

C220470pF1000V

R106600R0.25W

C305470nF630V

C2421000uF50V

+

D201EGP20D

R3011M20.25W

R10868K0.5W

C3091nF25V

R308470K0.25W

C1053.3nF50V

C114630V

R204250K0.25W

R204

D3031N4148

C200470pF1000V

L23110uH

5A

C231100uF200V

+

Q301FQP13N50C

C2121000uF50V

+

R2064K70.25W

T1EF42 VOGT

C101220uF450V

+

C3071uF MLCC50V

C10347uF50V

+

VR20130K

FS1230V/3A

C2011000uF50V

+

L22110uH

5A

BEAD101FERRITE BEAD

BD100

-+

R11868K0.5W

R30522K0.6W

D241FYPF0545

T301VOGT EF25 PFC

D1051N4937

D302EGP30J

C2411000uF50V

+

VR30110K

D211EGP20D

R3070.3R0.6W

R110S10K275

CONN3B2P-VH

C10447nF50V

CONN1B2P3-VH

D231EGP20K

R105470R0.25W

C111630V

C112630V

C2211000uF50V

+

R2011K0.25W

IC1KA5Q1265RFYDTU

F

C400

CONN2B9P-VH

C210470pF1000V

C240470pF1000V

D1031N4937

C2021000uF50V

+

L21110uH

5A

C206

100nF100V

D221FYPF0545

R3111M0.25W

LF100

R3096K0.25W

D3048V20.5W

D101N49376

C110250V

R30220K

0.25W

D1081N4007

R103

10R0.25W

C2221000uF50V

+

R2021K0.25W

C113630V

IC3KA431LZ

NTC1002R

C232100uF200V

+

C2111000uF50V

+

C107680pF1600V

R203

39K0.25W

IC2H11A817A

High/Low

180W-200W KA5Q1265RF Quasi-resonant Flyback with Input Power Factor Correction Using FAN7527B/FQP13N50CTypical Application – Color Televisions

23


FPS™ Design Guide

The circuit shown consists of a PFC stage built around the FAN7527B/FQP13N50C/EGP30J circuit and the quasi-resonant PWMstage built around the KA5Q1265RF/T1 circuit. This circuit is suited for input voltages in the range from around 195V to 265V.

The transition mode PFC stage generates a DC bus voltage of around 400V. The purpose of the stage is to reduce the harmonic con-tent of the input current drawn from the AC supply as required by the EN61000-3-2 standard. An additional benefit is that the inputpower factor is very high.

The KA5Q1265RF circuit generates the required output voltages using a multiple output flyback configuration. The device operates indiscontinuous mode and detects the point where the secondary current has dropped to zero. The device then switches on after adelay set by the circuit around C105. As the delay is chosen to be at the first minimum of the primary side voltage ring as itchanges from Vin + nVo to Vin - nVo the device is switched on at a low voltage, which reduces the switching loss. The switching frequency is therefore asynchronous and varies with the load. This reduces the visible effect of switching noise on the televisionscreen. Fixed frequency switching noise would be seen as diagonal lines on the screen. The turns ratio is chosen to be unusually lowfor a standard flyback because the output voltage on the main winding is exceptionally high. This keeps the reflected voltage nVo low.

If the load on a quasi-resonant flyback circuit is reduced, the switching frequency increases which causes a reduction in efficiency.

The KA5Q series has a burst mode of operation. In normal operation the High/Low signal is High. When this signal which is typicallysupplied by a microcontroller is Low, the current increases through the optocoupler, the feedback voltage goes to ground and thedevice enters burst mode. In this case the output voltages drop until the voltage supplied to the chip through the auxiliary windingdrops to around 12V. The device remains in hysteretic burst mode until the feedback voltage increases. In this low power mode, thePFC chip is deactivated via D304. In normal operation, the auxiliary winding voltage is around 24V, so there is sufficient voltage topower up the PFC chip. In burst mode, the FPS™ voltage is between 11V and 12V, so the FAN7527B chip is deactivated, as its supplyvoltage is around 8V lower than this.

• Complete PFC and PWM solution for a color television power supply– High efficiency (typically 90% at full load)– High power factor and low input current harmonics

• Quasi-resonant mode ideal for TV applications– High efficiency due to lower voltage switching– Asynchronous switching is not at constant frequency– Slower dV/dt causes lower internal radiated interference

• Supports low power standby– Hysteretic burst mode for KA5Q1265RF device– FAN7527B PFC controller deactivated at low power

Fairchild Devices DescriptionKA5Q1265RF Fairchild Power Switch (8A/quasi resonant)FAN7527B Transition mode PFC controllerFQP13N50C High Voltage MOSFET (13A/500V)EGP30J Fast Recovery Diode (3A/600V)1N4937 Fast Recovery Diode (1A/600V)GBU4M Bridge Rectifier (4A/1000V)BZX85C8V2 Zener Diode (8.2V)


180W-200W KA5Q1265RF Quasi-resonant Flyback with Input Power Factor Correction Using FAN7527B/FQP13N50CTypical Application – Color Televisions

Fairchild Devices DescriptionKA431 2.5V Reference (2.5V)H11A817A Transistor OptocouplerEGP20D Fast Recovery Diode (1A/200V)EGP20K Fast Recovery Diode (1A/600V)FYPF0545 Fast Recovery Diode (5A/45V)1N4007 Fast Recovery Diode (1A/1000V)1N4148 General Purpose Diode (10mA/100V)

24


FPS™ Design Guide

5V

12V

85V-265VAC Input

Primary 36 turns

Vcc 8 turns

5V 3 turns

12V 7 turns

40W output

Lp = 520uH EER3016

Vfb4

Vcc3

GND2

Drain1

NC5

Vstr6

12

7

8

10

3

2

2

1

4

5 6

1 3

42DB101

2KBP06 C103100uF400V

+

C205

47nF50V

C2011000uF

25V

+

R1045R

L201

C102

220nF275VAC

R101

560K/1W

D101UF4007

LF101:23mH

C10522uF50V

+

D1021N4148

ZD10122V

C101

220nF275VAC

C2041000uF

10V

+

R2011K

R10540K1W

R10240K1W

C104100uF400V

R20656K2W

R2021.2K

IC301H11A817A

R2045.6K

R2055.6K

IC101FSDM07652R

C2031000uF

10V

+

L202

RT101

IC201KA431

C2021000uF25V

+

CONN1B2P3-VH

T1:EER 3016

C301

4.7nFYCAP

-+

F101FUSE

C10647nF50V

D201MBRF10100

D202MBRF1045

R20310K

This shows a higher power isolated flyback application, sharing the same features as many of the lower power applications. Alower inductance value is used to ensure that the associated leakage inductance is also kept low in this application, rememberingthat snubber losses are proportional to the leakage inductance and to the square of the current.

• FPS containing PWM IC with co-packaged MOSFET solution is very robust and improves system reliability– Fully avalanche rated switch– Over current protection for secondary diode short circuit– Over voltage protection

• Current mode control gives excellent line and load regulation– Better regulation

• Overload protection distinguishes between temporary and permanent overload• Internal soft start reduces inrush current and output overshoot on turn on

Fairchild Devices DescriptionFSDM07652R Fairchild Power Switch (2.5A/70kHz)H11A817A OptocouplerKA431 2.5V Reference (2.5V)1N4007 General Purpose Diode (1A/1000V)1N4148 General Purpose Diode (10mA/100V)KBP06M Bridge Rectifier Diode (1.5A/600V)

40W Isolated Flyback Power SupplyTypical Application – AC Input Industrial Control, LCD Monitor


25


FPS™ Design Guide

Vfb4

Vcc3

GND2

Drain1

L&S5

3

2

2

1

4

5

1

2

1

2

1

2

6

10

R1045K10.25W

CONN1

B2P-VHR101200k

C20310nF50V

R2011K

R2021K

R20415K

R2053.9K

IC101FS6X1220RT

C201220uF25V

C202220uF25V

+

R10518R

R10218R

D201MBRF10100

D102

1N4148

IC201KA431

CONN2

B2P-VHC10312nF50V

+

R20333k

R103300K0.5W

C10547nF50V

C10447nF50V

C1021nF50V

C10147uF100V

++

CONN3

B2P-VH

D101UF4004

PCH11A817A

36V - 72VDC input 12V/2A output

Sleep ModeOn/Off Control

Primary 40 turnsVcc 18 turns12V 12 turns

Lp = 22uH EPC19T1: EPC19

The Fairchild Power Switch family is also useful in DC input applications. Here the FS6X1220 has a 200V MOSFET with RDS(on) ofless than 0.3W. The topology is very similar to the AC input flyback topology. One important difference is the additional L&S pin-which serves two functions. First, if the voltage drops below 2.55V, the device stops switching. If the voltage drops below 1.8V, thedevice goes into a shutdown mode which consumes only 300µA in the Vcc line.

• Flyback solution for this power level has good efficiency at a reasonable cost architecture can easily be expandedto support multiple outputs

• Dual function shut down pin– Undervoltage lockout below 2.55V– 300µA shutdown below 1.8V

• Full protection features of FPS family integrated on chip– Short circuit, overvoltage, temporary overload are no problem fully avalanche rated part

Fairchild Devices DescriptionFS6X1220RT Fairchild Power Switch (3.2A/300kHz)UF4004 Fast Recovery Diode (1A/400V)1N/FDLL4148 General Purpose Diode (10mA/100V)H11A817A Optocoupler (CTR = 80% – 160%)KA431 Shunt Regulator

24W Single Output 48V DC/DC Flyback ConverterTypical Application – 48V DC Input Industrial Equipment, Central Office, Basestations, Routers


26


FPS™ Design Guide

12

Drain1

GND2

Vcc3

Vfb4

L&S5

7

4

1

10

6

5

8

3

12

NC1

C2

E3

NC4 GND 5COMP 6

FB 7LED 8

R22 (NS)

390R0.6W

C2100nF250V

R130K

Q10

FDS7088N7 orFDZ5047N

D1SB380

T1

C11330uF16V

+

R211K

C31nF25V

U1FS6X1220RT

R15K61W

R17K61W

R2120K

R1010K 1%

C7

4.7nF25V

R8330R

C13 (NS)

330pF

C1247uF100V

+

C9330uF16V

+

D2MMBD914

C422uF50V

+

D3ES2B

R5

22R0.6W

C6

4.7nF25V

C8330uF16V

+

J1

Vout 3.3V/4AR14K61W

R93k 31%

C8100nF250V

U5FOD2741A

C547nF50V

30V-57VDC Input

3.3V/4AOutput

This solution is a interesting development of the 24W power supply concept. Here, synchronous rectification maximizes theefficiency of the power supply by using a MOSFET instead of a diode. Instead of having a loss of around 0.5V to 1.0V across a diode, the drop is now around 0.1V to 0.15V. This lead is to a 4% point increase in efficiency. An auxiliary winding drives the MOSFET.

Also shown in Fairchild’s FOD2741A which combines the optocoupler and reference functionality into one chip. All relevant nodesare accessible: LED drive, reference drive and the reference voltage itself.

• Implementation of Power over Ethernet with low component count– Cost effective solution

• High efficiency further improved by synchronous rectification– Four percentage points more efficiency lowers overall system power load

• FOD2741A combines optocoupler and reference in one chip– Lower component count and manufacturing costs

Fairchild Devices DescriptionFS6X1220RT Fairchild Power Switch (3.2A/300kHz)FOD2741A Optocoupler + ReferenceFDZ5047N BGA MOSFET (30V/2.9mΩ)SB380 Schottky Diode (3A/80V)ES2B General Purpose Diode (2A/100V)MMBD914 General Purpose Diode (200mA/100V)

Secondary Side Synchronous Rectification in a Power Over Ethernet ApplicationTypical Application – Power Over Ethernet, 48V DC Input Industrial Equipment


27


FPS™ Design Guide

Design Tools

AC to DC Designer• Download from website at

www.fairchildsemi.com/designcenter/acdc

• Allows quick and easy fly-back design process.

• Provides a lookup into a database of available devices.

• Gives a first-stab design for practical optimization.

• Can be used with controllers other than FPS.

Application Notes and Demo Boards• To download Application Notes and articles,

visit: www.fairchildsemi.com/fps

• Demoboards – available for a wide range ofapplications. Contact your local sales representative.

28


FPS™ Design Guide

Ordering Guide

29


FPS™ Design Guide

Notes

Americas Fairchild SemiconductorCustomer Response Center7701 Las Colinas Ridge,Suite 400 Irving, Texas 75063United States

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UKFairchild Semiconductor Ltd.Interface HouseInterface Business ParkWootton BassettSwindon SN4 8QEUnited KingdomTel: 44-1793-856856Fax: 44-1793-856857

The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to useand is not intended to be an exhaustive list of all such trademarks: ACEx™, Across the board. Around theworld.™, ActiveArray™, Bottomless™, CoolFET™, CROSSVOLT™, DOME™, EcoSPARK™, E2CMOS™,EnSigna™, FACT™, FACT Quiet Series™, FAST®, FASTr™, FPS™, FRFET™, GlobalOptoisolator™, GTO™,HiSeC™, I2C™, ImpliedDisconnect™, ISOPLANAR™, LittleFET™, MICROCOUPLER™, MicroFET™, MicroPak™,MICROWIRE™, MSX™, MSXPro™, OCX™, OCXPro™, OPTOLOGIC®, OPTOPLANAR™, PACMAN™, POP™,Power247™, PowerTrench®, Programmable Active Droop™, QFET®, QS™, QT Optoelectronics™, QuietSeries™, RapidConfigure™, RapidConnect™, SILENT SWITCHER®, SMART START™, SPM™, Stealth™,SuperFET™ SuperSOT™-3, SuperSOT™-6, SuperSOT™-8, SyncFET™, The Power Franchise™, TinyLogic®, TINYOPTO™ TruTranslation™, UHC™, UltraFET®, VCX™

Lit. No. 600301-003

For a complete listing of sales representatives and sales offices,visit www.fairchildsemi.com/cf/sales_contacts/

© 2004 Fairchild Semiconductor, All Rights Reserved

fps design guide - mouser electronics · 5 fps™ design guide when you plug into a power...

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