Fairchild FSQ0765RQ service manual

FSQ0765RQ Green-Mode Fairchild Power Switch (FPS™) for

FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation

April 2009

Quasi-Resonant Operation -

Features

! Optimized for Quasi-Resonant Converter (QRC) ! Low EMI through Variable Frequency Control and AVS

(Alternating Valley Switching)

! High-Efficiency through Minimum Voltage Switching ! Narrow Frequency Variation Range over Wide Load

and Input Voltage Variation

! Advanced Burst-Mode Operation for Low Standby

Power Consumption

! Simple Scheme for Sync Voltage Detection ! Pulse-by-Pulse Current Limit ! Various Protection functions: Overload Protection

(OLP), Over-Voltage Protection (OVP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) with Hysteresis, Output Short Protection (OSP)

! Under-Voltage Lockout (UVLO) with Hysteresis ! Internal Startup Circuit ! Internal High-Voltage Sense FET (650V) ! Built-in Soft-Start (17.5ms)

Applications

! Power Supply for LCD TV and Monitor, VCR, SVR,

STB, and DVD & DVD Recorder

! Adapter

Low EMI and High Efficiency

Description

A Quasi-Resonant Converter (QRC) generally shows lower EMI and higher power conversion efficiency than a conventional hard-switched converter with a fixed switching frequency. The FSQ-series is an integrated Pulse-Width Modulation (PWM) controller and SenseFET specifically designed for quasi-resonant operation and Alternating Valley Switching (AVS). The PWM controller includes an integrated fixed-frequency oscillator, Under-Voltage Lockout (UVLO), LeadingEdge Blanking (LEB), optimized gate driver, internal softstart, temperature-compensated precise current sources for a loop compensation, and self-protection circuitry. Compared with a discrete MOSFET and PWM controller solution, the FSQ-series can reduce total cost, component count, size, and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform that is well suited for cost-effective designs of quasi-resonant switching flyback converters.

Related Resources

Visit http://www.fairchildsemi.com/apnotes/ for:

! AN-4134: Design Guidelines for Offline Forward

Converters Using Fairchild Power Switch (FPS

! AN-4137: Design Guidelines for Offline Flyback

Converters Using Fairchild Power Switch (FPS

! AN-4140: Transformer Design Consideration for

Offline Flyback Converters Using Fairchild Power Switch (FPS

! AN-4141: Troubleshooting and Design Tips for

Fairchild Power Switch (FPS

! AN-4145: Electromagnetic Compatibility for Power

Converters

! AN-4147: Design Guidelines for RCD Snubber of

Flyback

! AN-4148: Audible Noise Reduction Techniques for

Fairchild Power Switch Fairchild Power Switch(FPS Applications

! AN-4150: Design Guidelines for Flyback Converters

Using FSQ-Series Fairchild Power Switch (FPS

FSQ0765RQ Rev. 1.0.1

™

)

™

) Flyback Applications

™

)

™

)

™)

™

)

Ordering Information

Maximum Output Power

Product

Number

FSQ0765RQWDTU TO-220F-6L -25 to +85°C 3.5A 1.6Ω 80W 90W 48W 70W

PKG.

(5)

Operating

Tem p.

Current

Limit

R

DS(ON)

Max.

230VAC±15%

Adapter

(3)

(2)

Open

Frame

(4)

Adapter

Notes:

1. The junction temperature can limit the maximum output power.

2. 230V

or 100/115VAC with doubler.

AC

3. Typical continuous power in a non-ventilated enclosed adapter measured at 50°C ambient temperature.

4. Maximum practical continuous power in an open-frame design at 50°C ambient.

For Fairchild’s definition of “green” Eco Status, please visit:

5.

http://www.fairchildsemi.com/company/green/rohs_green.html. Eco Status: RoHS.

(1)

85-265V

(3)

AC

Open

Frame

(4)

FSCM0765R FSDM0765RB

FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation

Replaces

Devices

FSQ0765RQ Rev. 1.0.1 2

Application Diagram

AC

IN

FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation

V

O

V

str

Drain

Internal Block Diagram

0.35/0.55 V

Burst

ref

OSP

FB

VCCV

I

delayIFB

4

tON < t

after SS

PWM

Sync

FB

V

CC

GND

Figure 1. Typical Flyback Application

Sync

5

AVS

SoftStart

PWM

3R

R

OSC

LEB

250ns

FSQ0765R Rev.00

V

str

V

CC

Drain

3 16

V

ref

good

V

CC

Q

S

R

Q

Gate

driver

8V/12V

V

OSP

V

SD

V

OVP

LPF

TSD

VCC good

SQQ

R

AOCP

V

OCP

(1.1V)

FSQ0765R Rev.00

2

GND

Figure 2. Internal Block Diagram

FSQ0765RQ Rev. 1.0.1 3

Pin Configuration

6. V

5. Sync

4. FB

3. V

2. GND

1. Drain

FSQ0765R Rev.00

Figure 3. Pin Configuration (Top View)

Pin Definitions

Pin # Name Description

1DrainSenseFET drain. High-voltage power SenseFET drain connection.

2GNDGround. This pin is the control ground and the SenseFET source.

3V

4FB

5 Sync

6V

Power Supply. This pin is the positive supply input. This pin provides internal operating current for

CC

both startup and steady-state operation.

Feedback. This pin is internally connected to the inverting input of the PWM comparator. The collector of an opto-coupler is typically tied to this pin. For stable operation, a capacitor should be placed between this pin and GND. If the voltage of this pin reaches 6V, the overload protection triggers, which shuts down the FPS.

Sync.

This pin is internally connected to the sync-detect comparator for quasi-resonant switching.

In normal quasi-resonant operation, the threshold of the sync comparator is 1.2V/1.0V.

Startup. This pin is connected directly, or through a resistor, to the high-voltage DC link. At start-up, the internal high-voltage current source supplies internal bias and charges the external

str

capacitor connected to the VCC pin. Once VCC reaches 12V, the internal current source is disabled. It is not recommended to connect V

and Drain together.

str

FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation

str

CC

FSQ0765RQ Rev. 1.0.1 4

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. T

Symbol Parameter Min. Max. Unit

V

str

V

DS

V

CC

V

FB

V

Sync

I

DM

I

D

E

AS

P

D

T

J

T

A

T

STG

ESD Electrostatic Discharge Capability

V

Pin Voltage 500 V

str

Drain Pin Voltage 650 V

Supply Voltage 20 V

Feedback Voltage Range -0.3 13.0 V

Sync Pin Voltage -0.3 13.0 V

Drain Current Pulsed 14.4 A

Continuous Drain Current

(6)

Single Pulsed Avalanche Energy

Total Power Dissipation(Tc=25°C) 45 W

Operating Junction Temperature Internally limited °C

Operating Ambient Temperature -25 +85 °C

Storage Temperature -55 +150 °C

= 25°C, unless otherwise specified.

A

TC = 25°C 3.6

T

= 100°C 2.28

(7)

C

Human Body Model 2

Charged Device Model 2

A

570 mJ

kV

FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation

Notes:

6. Repetitive rating: Pulse width limited by maximum junction temperature.

7. L=81mH, starting TJ=25°C.

Thermal Impedance

TA = 25°C unless otherwise specified.

Symbol Parameter Value Unit

(9)

(8)

50

2.8

θ

JA

θ

JC

Junction-to-Ambient Thermal Resistance

Junction-to-Case Thermal Resistance

Notes:

8. Free standing with no heat-sink under natural convection.

9. Infinite cooling condition - refer to the SEMI G30-88.

°

C/W

°

C/W

FSQ0765RQ Rev. 1.0.1 5

FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation

Electrical Characteristics

TA = 25°C unless otherwise specified.

Symbol Parameter Condition Min. Typ. Max. Unit

SENSEFET SECTION

BV

DSS

I

DSS

R

DS(ON)

C

OSS

t

d(on)

t

r

t

d(off)

t

f

CONTROL SECTION

t

ON.MAX

t

B

t

W

f

S

Δf

t

AVS

V

AVS

t

SW

I

FB

D

MIN

V

START

V

STOP

t

S/S

BURST-MODE SECTION

V

BURH

V

BURL

Hysteresis 200 mV

Drain Source Breakdown Voltage VCC = 0V, ID = 100µA 650 V

Zero-Gate-Voltage Drain Current VDS = 520V, VGS = 0V 300 µA

Drain-Source On-State Resistance TJ = 25°C, ID = 1.8A 1.3 1.6 Ω

Output Capacitance VGS = 0V, VDS = 25V, f = 1MHz 125 pF

Turn-On Delay Time

Rise Time 102 ns

Turn-Off Delay Time 63 ns

VDD = 325V, ID = 6.5A

27 ns

Fall Time 65 ns

Maximum On Time TJ = 25°C 8.8 10.0 11.2 µs

Blanking Time TJ = 25°C, V

Detection Time Window TJ = 25°C, V

= 5V 13.5 15.0 16.5 µs

sync

= 0V 6.0 µs

sync

Initial Switching Frequency 59.6 66.7 75.8 kHz

Switching Frequency Variation

S

AVS Triggering Threshold

(11)

Switching Time Variance by AVS

(11)

On Time

Feedback Voltage

(11)

-25°C < TJ < 85°C ±5 ±10 %

at V

= 240VDC, Lm = 360μH

IN

(AVS triggered when V

<spec.)

& t

AVS

Sync = 500kHz sine input V

= 1.2V, t

FB

ON

= 4.0µs

>spec

13.5 20.5 µs

4.0 µs

1.2 V

Feedback Source Current VFB = 0V 700 900 1100 µA

Minimum Duty Cycle VFB = 0V 0 %

UVLO Threshold Voltage

After turn-on 7 8 9 V

11 12 13 V

Internal Soft-Start Time With free-running frequency 17.5 ms

0.45 0.55 0.65 V

Burst-Mode Voltages TJ = 25°C, tPD = 200ns

(10)

0.25 0.35 0.45 V

Note:

10. Propagation delay in the control IC.

Continued on the following page...

FSQ0765RQ Rev. 1.0.1 6