Fairchild FAN6755W service manual

FAN6755W / FAN6755UW mWSaver

™

PWM Controller

FAN6755W / FAN6755UW — mWSaver™ Controller

June 2011

Features

 mWSaver

Class Standby Power

o <100mW at 25mW Load for LCDM Adaptor o Internal High-Voltage JFET Startup o Low Operating Current Maximum: 2mA o Adaptive Decreasing of PWM Frequency to

o Feedback Impedance Switching During

™

Technology Provides Industry’s Best-in-

23KHz at Light-Load Condition, Improved Light-Load Efficiency

Minimum Load or No Load

 Proprietary Asynchronous Frequency Hopping

Reduced EMI

 Fixed PWM Frequency: 65KHz (FAN6755W),

130KHz (FAN6755UW)

 Internal Leading-Edge Blanking  Built-in Synchronized Slope Compensation  Auto-Restart Protection: Feedback Open-Loop

Protection (OLP), V (OVP), Over-Temperature Protection (OTP), and Line Over-Voltage Protection

Over-Voltage Protection

DD

 Soft Gate Drive with Clamped Output Voltage: 18V  V

Under-Voltage Lockout (UVLO)

DD

 Programmable Constant Power Limit (Full AC

Input Range)

 Internal OTP Sensor with Hysteresis  Build-in 5ms Soft-Start Function  Input Voltage Sensing (V

Protection with Hysteresis and Line Over-Voltage Protection

Pin) for Brown-In/Out

IN

Description

This highly integrated PWM controller provides several features to enhance the performance of flyback converters.

To minimize standby power consumption, a proprietary adaptive green-mode function reduces switching frequency at light-load condition. To avoid acousticnoise problems, the minimum PWM frequency is set above 23kHz. This green-mode function enables the power supply to meet international power conservation requirements, such as Energy Star high-voltage startup circuitry, the power loss caused by bleeding resistors is also eliminated. To further reduce power consumption, FAN6755W/UW uses the BiCMOS process, which allows an operating current of only 2mA. The standby power consumption can be under 100mW for most of LCD monitor power supply designs.

FAN6755W/UW integrates a frequency-hopping function that reduces EMI emission of a power supply with minimum line filters. Its built-in synchronized slope compensation achieves a stable peak-current-mode control and improves noise immunity. The proprietary, external line compensation ensures constant output power limit over a wide AC input voltage range from 90V

to 264VAC.

AC

FAN6755W/UW provides many protection functions. The internal feedback open-loop protection circuit protects the power supply from open feedback loop condition or output short condition. It also has line under-voltage protection (brownout protection) and overvoltage protection using an input voltage sensing pin (V

).

IN

FAN6755W/UW is available in a 7-pin SOP package.

®

. With the internal

Applications

General-purpose switched-mode power supplies and flyback power converters, including:

 LCD Monitor Power Supply  Open-Frame SMPS

ENERGY STAR® is a registered trademark of the U.S. Department of Energy and the U.S. Environmental Protection Agency.

Ordering Information

Operating

Part Number

Temperature

Package

Range

FAN6755WMY -40 to +105°C

FAN6755UWMY -40 to +105°C 130kHz Reel & Tape

7-Lead, Small Outline Integrated Circuit (SOIC), Depopulated JEDEC MS-112, .150 Inch Body

PWM

Frequency

65kHz Reel & Tape

Packing

Method

Application Diagram

FAN6755W / FAN6755UW — mWSaver™ Controller

Figure 1. Typical Application

Internal Block Diagram

HV

7

HV

Startup

VDD

6

DD-OFF

/V

DD-ON

V

DD-OVP

V

/ V

IN_ON

IN_OFF

1

VIN

High/Low Line Compensation

5.3V

UVLO

Debounce

Brownout Protection

Debounce

Re-start

OTP

4

GND

OLP

Protection

QS

R

Soft-Start

Comparator

Current Limit

Comparator

PWM

Comparator

OLP

Delay

Comparator

Brownout Protection

Clock

Generator

Internal

BIAS

OVP

V

Limit

V

rotect

IN-P

…

Green

Mode

Figure 2. Internal Block Diagram

OLP

OTP OVP OLP V

IN-P

rotect

Soft-Start

Compensation

Soft

Driver

V

Limit

Slope

R

V

FB-OLP

3R

V

DD

Circuit Blanking

5.3V

5

3

2

FAN6755W / FAN6755UW — mWSaver™ Controller

GATE

SENSE

FB

Marking Information

ZXYTT 6755 WTPM

ZXYTT 6755U WTPM

Figure 3. Top Mark

Z: Plant Code X: 1-Digit Year Code Y: 1-Digit Week Code TT: 2-Digit Die Run Code T: Package Type (M:SOP) P: Y=Green Package M: Manufacture Flow Code

Pin Configuration

VIN

FB

SENSE

GND

Figure 4. Pin Configuration (Top View)

SOP-7

17

HV

2

3

6

54

VDD

GATE

Pin Definitions

Pin # Name Description

Line-voltage detection. The line-voltage detection is used for brownout protection with hysteresis.

1 VIN

2 FB

3 SENSE

4 GND Ground

5 GATE The totem-pole output driver. Soft-driving waveform is implemented for improved EMI.

6 VDD

7 HV For startup, this pin is pulled HIGH to the line input or bulk capacitor via resistors.

Constant output power limit over universal AC input range is also achieved using this VIN pin. It is suggested to add a low-pass filter to filter out line ripple on the bulk capacitor. Pulling VIN HIGH also triggers auto-restart protection.

The signal from the external compensation circuit is fed into this pin. The PWM duty cycle is determined in response to the signal on this pin and the current-sense signal on the SENSE pin.

Current sense. The sensed voltage is used for peak-current-mode control and cycle-by-cycle

current limiting.

Power supply. The internal protection circuit disables PWM output as long as V OVP trigger point.

exceeds the

DD

FAN6755W / FAN6755UW — mWSaver™ Controller

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only.

Symbol Parameter Min. Max. Unit

V

DC Supply Voltage

VDD

VFB FB Pin Input Voltage -0.3 7.0 V

V

SENSE Pin Input Voltage -0.3 7.0 V

SENSE

V

VIN Pin Input Voltage -0.3 7.0 V

VIN

VHV HV Pin Input Voltage 700 V

PD

JA

Power Dissipation (T

Thermal Resistance (Junction-to-Air) 150

TJ Operating Junction Temperature -40 +125

T

Storage Temperature Range -55 +150

STG

TL Lead Temperature (Wave Soldering or IR, 10 Seconds) +260

Human Body Model,

ESD

JEDEC: JESD22-A114

Charged Device Model, JEDEC: JESD22-C101

Notes:

1. All voltage values, except differential voltages, are given with respect to the network ground terminal.

2. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.

3. ESD with HV pin: CDM=2000V (FAN6755W) or 1500V (FAN6755UW), and HBM=3500V.

(1, 2)

30 V

＜50°C)

A

400 mW

C/W

C

All Pins Except HV Pin 5.5

kV

All Pins Except HV Pin 2.0

FAN6755W / FAN6755UW — mWSaver™ Controller

Electrical Characteristics

VDD=15V, TA=25C, unless otherwise noted.

Symbol Parameter Conditions Min. Typ. Max. Units

VDD Section

VOP Continuously Operating Voltage Full Load 22 V

V

Start Threshold Voltage 15 16 17 V

DD-ON

V

Protection Mode 9 10 11 V

DD-OFF

UVLO Normal Mode 6.8 7.8 8.8 V

I

Startup Current V

DD-ST

I

Operating Supply Current VDD=15V, GATE Open 2 mA

DD-OP

I

Internal Sink Current

DD-OLP

V

DD-OLP

V

DD-OVP

t

D-VDDOVP

Threshold Voltage on V JFET Turn-On

VDD Over-Voltage Protection 25 26 27 V

VDD Over-Voltage Protection Debounce Time

for HV

DD

HV Section

IHV Supply Current Drawn from HV Pin

I

Leakage Current after Startup

HV-LC

– 0.16V 30 µA

DD-ON

V

TH-OLP

+0.1V

30 60 90 µA

6.5 7.5 8.0 V

75 125 200 µs

VDC=120V, VDD=10µF, V

=0V

DD

HV=700V, VDD=V

+1V

OFF

DD-

2.0 3.5 5.0

1 20

mA

µA

Figure 5. V

Behavior

DD

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