Fairchild FSQ0265RN service manual

FSQ0365, FSQ0265, FSQ0165, FSQ321

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

August 2011

Green Mode Fairchild Power Switch (FPS™)

for Valley Switching Converter – Low EMI and High Efficiency

Features

 Optimized for Valley Switching Converter (VSC)

 Low EMI through Variable Frequency Control and

Inherent Frequency Modulation

 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

 Pulse-by-Pulse Current Limit

 Protection Functions: Overload Protection (OLP),

Over-Voltage Protection (OVP), Abnormal OverCurrent Protection (AOCP), Internal Thermal Shutdown (TSD)

 Under-Voltage Lockout (UVLO) with Hysteresis

 Internal Startup Circuit

 Internal High-Voltage SenseFET: 650V

 Built-in Soft-Start: 15ms

Applications

Description

A Valley Switching Converter 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 valley switching operation with minimal external components. The PWM controller includes an integrated fixed-frequency oscillator, under-voltage lockout, Leading-Edge Blanking (LEB), optimized gate driver, internal soft-start, temperature-compensated precise current sources for loop compensation, and self-protection circuitry.

Compared with discrete MOSFET and PWM controller solutions, the FSQ-series reduces total cost, component count, size and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform for cost-effective designs of valley switching fly-back converters.

Related Application Notes

AN-4137 - Design Guidelines for Offline Flyback



Converters Using Fairchild Power Switch (FPS™)

 AN-4141 - Troubleshooting and Design Tips for

Fairchild Power Switch (FPS™) Flyback Applications

 Power Supplies for DVP Player, DVD Recorder,

Set-Top Box

 Adapter

 Auxiliary Power Supply for PC, LCD TV, and PDP TV

 AN-4147 - Design Guidelines for RCD Snubber of

Flyback Converters

 AN-4150 - Design Guidelines for Flyback

Converters Using FSQ-series Fairchild Power Switch (FPS™)

 AN-4134 - Design Guidelines for Off-line Forward

Converters Using Fairchild Power Switch (FPS™)

Ordering Information

(3)

(1)

Open

Frame

(4)

FSDM0265RN

FSDM0265RNB

FSDM0365RN

FSDM0365RNB

Maximum Output Table

Part Number Package

Operating

Temperature

Current

Limit

R

DS(ON)

(Max.)

230VAC ±15%

Adapter

(3)

(2)

85-265VAC

Open

Frame

(4)

Adapter

FSQ321 8-DIP

FSQ321L 8-LSOP

-40 to +85°C 0.6A 19Ω 8W 12W 7W 10W

FSQ321LX

8-LSOP (Tape &

Reel)

FSQ0165RN 8-DIP

FSQ0165RL 8-LSOP

-40 to +85°C 0.9A 10Ω 10W 15W 9W 13W FSDL0165RN

FSQ0165RLX

8-LSOP (Tape &

Reel)

FSQ0265RN 8-DIP

FSQ0265RL 8-LSOP

FSQ0365RN 8-DIP

FSQ0365RL 8-LSOP

-40 to +85°C 1.2A 6Ω 14W 20W 11W 16W

-40 to +85°C 1.5A 4.5Ω 17.5W 25W 13W 19W

Notes:

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

2. 230V

or 100/115VAC with voltage doubler. The maximum power with CCM operation

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 temperature.

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Replaces

Devices

FSDL321

FSDM311

Application Circuit

AC

IN

Sync

V

PWM

fb

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Vo

V

str

V

cc

Drain

GND

Internal Block Diagram

0.35/0.55 V

Burst

V

ref

CC

I

FB

V

SD

Sync

V

ovp

delay

3R

6V

Vfb

3

Figure 1. Typical Flyback Application

Sync

4

+

-

R

0.7V/0.2V

SoftStart

2.5 s Time Delay

+

-

PWM

TSD

VCCGood

OSC

LEB

200ns

SQQ

R

SQQ

R

Vstr

5

V

ref

VCCGood

AOCP

Gate

Driver

Vcc

2 8

+

-

8V/12V

V

OCP

(1.1V)

Drain

76

1

GND

FSQ0365RN Rev.00

Figure 2. Internal Block Diagram

Pin Assignments

Figure 3. Pin Configuration (Top View)

Pin Definitions

Pin# Name Description

1 GND SenseFET source terminal on primary side and internal control ground.

Positive supply voltage input. Although connected to an auxiliary transformer winding,

2 VCC

3 Vfb

4 Sync

5 Vstr

6, 7, 8 Drain

current is supplied from pin 5 (Vstr) via an internal switch during startup (see Figure 2).

It is not until V

reaches the UVLO upper threshold (12V) that the internal startup switch

CC

opens and device power is supplied via the auxiliary transformer winding.

The feedback voltage pin is the non-inverting input to the PWM comparator. It has a

0.9mA current source connected internally while a capacitor and opto-coupler are typically connected externally. There is a time delay while charging external capacitor C to 6V using an internal 5A current source. This delay prevents false triggering under transient conditions, but still allows the protection mechanism to operate under true overload conditions.

This pin is internally connected to the sync-detect comparator for valley switching. Typically the voltage of the auxiliary winding is used as Sync input voltage and external resistors and capacitor are needed to make delay to match valley point. The threshold of the internal sync comparator is 0.7V/0.2V.

This pin is connected to the rectified AC line voltage source. At startup, the internal switch supplies internal bias and charges an external storage capacitor placed between the Vcc pin and ground. Once the V

reaches 12V, the internal switch is opened.

CC

The drain pins are designed to connect directly to the primary lead of the transformer and are capable of switching a maximum of 650V. Minimizing the length of the trace connecting these pins to the transformer decreases leakage inductance.

from 3V

fb

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

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

Vstr Pin Voltage 500 V

STR

V

Drain Pin Voltage 650 V

DS

V

Supply Voltage 20 V

CC

V

Feedback Voltage Range -0.3 9.0 V

FB

V

Sync Pin Voltage -0.3 9.0 V

Sync

IDM Drain Current Pulsed

EAS Single Pulsed Avalanche Energy

P

Total Power Dissipation 1.5 W

D

T

Recommended Operating Junction Temperature -40 Internally Limited

J

TA Operating Ambient Temperature -40 +85

T

Storage Temperature -55 +150

STG

ESD

Human Body Model; JESD22-A114

Machine Model; JESD22-A115

Notes:

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

6. L=51mH, starting T

=25°C.

J

(6)

(7)

=25°C, unless otherwise specified.

A

FSQ0365 12.0

FSQ0265 8.0

FSQ0165 4.0

FSQ321 1.5

FSQ0365 230

FSQ0265 140

FSQ0165 50

FSQ321 10

CLASS 1C

CLASS B

A

mJ

C

Thermal Impedance

Symbol Parameter Value Unit

(7)

8-DIP

Notes:

7. All items are tested with the standards JESD 51-2 and 51-10 (DIP).

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

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

10. Measured on the package top surface.

θJA Junction-to-Ambient Thermal Resistance

θJC Junction-to-Case Thermal Resistance

θJT Junction-to-Top Thermal Resistance

(9)

(10)

(8)

80

20

°C/W

35

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Electrical Characteristics

T A=25C unless otherwise specified.

Symbol Parameter Condition Min. Typ. Max. Unit

SenseFET Section

BV

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

DSS

I

Zero-Gate-Voltage Drain Current VDS=650V 100 µA

DSS

R

C

DS(ON)

C

ISS

OSS

RSS

t

d(on)

Drain-Source OnState Resistance

(11)

Input Capacitance

Output Capacitance

Reverse Transfer Capacitance

Turn-On Delay

tr Rise Time

t

Turn-Off Delay

d(off)

tf Fall Time

Burst-Mode Section

V

BURH

V

BURL

V

BUR(HYS)

Burst-Mode Voltage T

0.25 0.35 0.45 V

200 mV

Continued on the following page…

FSQ0365

FSQ0265 5.0 6.0

FSQ0165 8.0 10.0

TJ=25C, ID=0.5A

FSQ321

FSQ0365

FSQ0265 550

FSQ0165 250

VGS=0V, VDS=25V, f=1MHz

FSQ321 162

FSQ0365

FSQ0265 38

FSQ0165 25

VGS=0V, VDS=25V, f=1MHz

FSQ321 18

FSQ0365

FSQ0265 17.0

FSQ0165 10.0

VGS=0V, VDS=25V, f=1MHz

FSQ321 3.8

FSQ0365

FSQ0265 20.0

FSQ0165 12.0

VDD=350V, ID=25mA

FSQ321 9.5

FSQ0365

FSQ0265 15

FSQ0165 4

VDD=350V, ID=25mA

FSQ321 19

FSQ0365

FSQ0265 55.0

FSQ0165 30.0

VDD=350V, ID=25mA

FSQ321 33.0

FSQ0365

FSQ0265 25

FSQ0165 10

VDD=350V, ID=25mA

FSQ321 42

=25°C, tPD=200ns

J

(12)

3.5 4.5



14.0 19.0

315

pF

47

pF

9.0

pF

11.2

ns

34

ns

28.2

ns

32

ns

0.45 0.55 0.65 V

Electrical Characteristics (Continued)

T A=25C unless otherwise specified.

Symbol Parameter Conditions Min. Typ. Max. Unit

Control Section

t

Maximum On Time1

ON.MAX1

t

Maximum On Time2 FSQ321 TJ=25°C 6.35 7.06 7.77 µs

ON.MAX2

tB1 Blanking Time1

tB2 Blanking Time2 FSQ321 7.5 8.2 µs

tW Detection Time Window TJ=25°C, V

fS

Switching Frequency Variation

IFB Feedback Source Current VFB=0V 700 900 1100 µA

D

Minimum Duty Cycle VFB=0V 0 %

MIN

V

START

V

STOP

t

S/S1

t

S/S2

UVLO Threshold Voltage After Turn-on

7 8 9 V

Internal Soft-Start Time 1

Internal Soft-Start Time 2 FSQ321

Protection Section

I

Peak Current Limit

LIM

VSD Shutdown Feedback Voltage VCC=15V 5.5 6.0 6.5 V

I

Shutdown Delay Current VFB=5V 4.0 5.0 6.0 µA

DELAY

t

Leading-Edge Blanking Time

LEB

V

Over-Voltage Protection VCC=15V, VFB=2V 5.5 6.0 6.5 V

OVP

t

OVP

Over-Voltage Protection Blanking Time

TSD Thermal Shutdown Temperature

Sync Section

VSH

VSL 0.14 0.20 0.26 V

t

Sync

Sync Threshold Voltage

Sync Delay Time

(13,14)

Total Device Section

IOP

I

START

Operating Supply Current (Control Part Only)

Start Current

ICH Startup Charging Current VCC=0V, V

V

Minimum V

STR

Supply Voltage 26 V

STR

Notes:

11. Pulse test: Pulse-Width=300s, duty=2%.

12. Propagation delay in the control IC.

13. Though guaranteed, it is not 100% tested in production.

14. Includes gate turn-on time.

All but FSQ321

(14)

TJ=25°C 10.5 12.0 13.5 µs

13.2 15.0 16.8 µs

=0V 3.0 µs

sync

-25C < TJ < 85C

±5 ±10 %

11 12 13 V

All but FSQ321

FSQ0365 T

FSQ0265 TJ=25°C, di/dt=200mA/µs 1.06 1.20 1.34

FSQ0165 TJ=25°C, di/dt=175mA/µs 0.8 0.9 1.0

With Free-Running Frequency

=25°C, di/dt=240mA/µs 1.32 1.50 1.68

J

15 ms

10 ms

A

FSQ321 TJ=25°C, di/dt=125mA/µs 0.53 0.60 0.67

(13)

200 ns

2 3 4 µs

(13)

125 140 155 °C

0.55 0.70 0.85 V

300 ns

VCC=15V 1 3 5 mA

V

CC=VSTART

(Before V

- 0.1V Reaches V

CC

=Minimum 40V 0.65 0.85 1.00 mA

STR

START

270 360 450 µA

)

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Comparison Between FSDM0x65RNB and FSQ-Series

Function FSDM0x65RNB FSQ-Series Advantages of FSQ-Series

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Operation Method

EMI Reduction

Burst-Mode

Operation

Protection AOCP

Constant

Frequency PWM

Frequency

Modulation

Fixed Burst Peak

Valley Switching

Operation

Valley Switching &

Inherent Frequency

Modulation

Advanced Burst-

Mode

 Improved efficiency by valley switching  Reduced EMI noise

 Reduce EMI noise in two ways

 Improved standby power by valley switching also in

burst-mode

 Because the current peak during burst operation is

dependent on V noise

, it is easier to solve audible

FB

 Improved reliability through precise abnormal over-

current protection

Typical Performance Characteristics

Characteristic graphs are normalized at T

=25°C.

A

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 4. Operating Supply Current (IOP) vs. TA Figure 5. UVLO Start Threshold Voltage (V

vs. TA

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

START

)

Figure 6. UVLO Stop Threshold Voltage (V

STOP

)

Figure 7. Startup Charging Current (ICH) vs. TA

vs. TA

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 8. Initial Switching Frequency (fS) vs. TA Figure 9. Maximum On Time (t

) vs. TA

ON.MAX

Typical Performance Characteristics (Continued)

Characteristic graphs are normalized at TA=25°C.

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 10. Blanking Time (tB) vs. TA Figure 11. Feedback Source Current (IFB) vs. TA

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 12. Shutdown Delay Current (I

DELAY

) vs. TA

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 14. Burst Mode Low Threshold Voltage (V

vs. TA

Figure 13. Burst Mode High Threshold Voltage (V

vs. TA

1.2

1.0

0.8

burl

)

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 15. Peak Cu rrent Limit (I

LIM

) vs. TA

burh

)

Typical Performance Characteristics (Continued)

Characteristic graphs are normalized at TA=25°C.

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 16. Sync High Threshold (VSH) vs. TA Figure 17. Sync Low Threshold Voltage (VSL) vs. TA

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

1.2

1.0

0.8

0.6

Normalized

0.4

0.2

0.0

-25 0 25 50 75 100 125

Temperature [°C]

Figure 18. Shutdown Feedback Voltage (VSD) vs. TA Figure 19. Over-Voltage Protection (VOP) vs. TA

Functional Description

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

1. Startup: At startup, an internal high-voltage current

source supplies the internal bias and charges the external capacitor (C illustrated in Figure 20. When V

) connected to the VCC pin, as

a

reaches 12V, the

CC

FPS™ begins switching and the internal high-voltage current source is disabled. The FPS continues its normal switching operation and the power is supplied from the auxiliary transformer winding unless V

goes

CC

below the stop voltage of 8V.

V

DC

C

a

8V/12V

V

CC

2 5

I

CH

VCC good

V

str

V

ref

Internal

FSQ0365RN Rev.00

Bias

Figure 20. Startup Circuit

2. Feedback Control: FPS employs Current Mode

control, as shown in Figure 21. An opto-coupler (such as FOD817A) and shunt regulator (such as KA431) are

FOD817A

KA431

V

FB

C

B

V

O

FSQ0365RN Rev. 00

Figure 21. Pulse-Width-Modulation (PWM) Circuit

3. Synchronization: The FSQ-series employs a valley

switching technique to minimize the switching noise and loss. The basic waveforms of the valley switching converter are shown in Figure 22. To minimize the MOSFET's switching loss, the MOSFET should be turned on when the drain voltage reaches its minimum value, as shown in Figure 22. The minimum drain voltage is indirectly detected by monitoring the V winding voltage, as shown in Figure 22.

V

ds

V

DC

V

ref

CC

I

delay

3

V

SD

I

D1 D2

V

FB

Gate

driver

SenseFET

R

sense

OSC

3R

+

*

FB

R

-

OLP

CC

V

RO

V

RO

often used to implement the feedback network. Comparing the feedback voltage with the voltage across the R

resistor makes it possible to control the

SENSE

switching duty cycle. When the reference pin voltage of

V

sync

t

F

V

(6V)

ovp

the shunt regulator exceeds the internal reference voltage of 2.5V, the opto-coupler LED current increases, pulling down the feedback voltage and reducing the duty cycle. This event typically occurs when input voltage is increased or output load is decreased.

2.1 Pulse-by-Pulse Current Limit: Because Current

MOSFET Gate

0.7V

0.2V

300ns Delay

Mode control is employed, the peak current through the SenseFET is limited by the inverting input of PWM comparator (V

*), as shown in Figure 21. Assuming

FB

ONON

that the 0.9mA current source flows only through the internal resistor (3R + R = 2.8kΩ), the cathode voltage of diode D2 is about 2.5V. Since D1 is blocked when the feedback voltage (V

) exceeds 2.5V, the maximum

FB

voltage of the cathode of D2 is clamped at this voltage, clamping V

*. Therefore, the peak value of the current

FB

through the SenseFET is limited.

2.2 Leading-Edge Blanking (LEB): At the instant the internal SenseFET is turned on, a high-current spike usually occurs through the SenseFET, caused by primary-side capacitance and secondary-side rectifier reverse recovery. Excessive voltage across the R

sense

resistor would lead to incorrect feedback operation in the Current Mode PWM control. To counter this effect, the FPS employs a leading-edge blanking (LEB) circuit. This circuit inhibits the PWM comparator for a short time (t

) after the SenseFET is turned on.

LEB

Figure 22. Valley Resonant Switching Waveforms

4. Protection Circuits: The FSQ-series has several

self-protective functions, such as Overload Protection (OLP), Abnormal Over-Current protection (AOCP), Over-Voltage Protection (OVP), and Thermal Shutdown (TSD). All the protections are implemented as AutoRestart Mode. Once the fault condition is detected, switching is terminated and the SenseFET remains off. This causes V Under-Voltage Lockout (UVLO) stop voltage of 8V, the

to fall. When VCC falls down to the

CC

protection is reset and the startup circuit charges the V

capacitor. When the VCC reaches the start voltage

CC

of 12V, the FSQ-series resumes normal operation. If the fault condition is not removed, the SenseFET remains off and V

drops to stop voltage again. In this manner,

CC

FSQ0365RN Rev.00

the auto-restart can alternately enable and disable the switching of the power SenseFET until the fault condition is eliminated. Because these protection circuits are fully integrated into the IC without external components, the reliability is improved without increasing cost.

V

FB

6.0V

FSQ0365RN Rev.00

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Overload protection

Fault

V

12V

8V

Power

DS

on

CC

occurs

Fault

removed

t

FSQ0365RN Rev. 00

Normal

operation

Fault

situation

Normal

operation

Figure 23. Auto-Restart Protection Waveforms

4.1 Overload Protection (OLP): Overload is defined as

the load current exceeding its normal level due to an unexpected abnormal event. In this situation, the protection circuit should trigger to protect the SMPS. However, even when the SMPS is in the normal operation, the overload protection circuit can be triggered during load transition. To avoid this undesired operation, the overload protection circuit is designed to trigger only after a specified time to determine whether it is a transient situation or a true overload situation. Because of the pulse-by-pulse current limit capability, the maximum peak current through the SenseFET is limited, and therefore the maximum input power is restricted with a given input voltage. If the output consumes more than this maximum power, the output voltage (V

) decreases below the set voltage. This

O

reduces the current through the opto-coupler LED, which also reduces the opto-coupler transistor current, thus increasing the feedback voltage (V

). If VFB

FB

exceeds 2.8V, D1 is blocked and the 5µA current source starts to charge CB slowly up to V V

continues increasing until it reaches 6V, when the

FB

. In this condition,

CC

switching operation is terminated, as shown in Figure

24. The delay for shutdown is the time required to charge CB from 2.8V to 6V with 5µA. A 20 ~ 50ms delay is typical for most applications.

2.8V

t12= CFB*(6.0-2.8)/I

t

1

delay

t

2

Figure 24. Overload Protection

4.2 Abnormal Over-Current Protection (AOCP)

: When the secondary rectifier diodes or the transformer pins are shorted, a steep current with extremely high-di/dt can flow through the SenseFET during the LEB time. Even though the FSQ-series has Overload Protection (OLP), it is not enough to protect the FSQ-series in that abnormal case, since severe current stress is imposed on the SenseFET until OLP triggers. The FSQ-series has an internal Abnormal Over-Current Protection (AOCP) circuit as shown in Figure 25. When the gate turn-on signal is applied to the power SenseFET, the AOCP block is enabled and monitors the current through the sensing resistor. The voltage across the resistor is compared with a preset AOCP level. If the sensing resistor voltage is greater than the AOCP level, the set signal is applied to the latch, resulting in the shutdown of the SMPS.

3R

R

FSQ0365RN Rev.00

AOCP

PWM

OSC

LEB

200ns

SQQ

R

Gate

driver

R

+

-

sense

V

OCP

1

GND

Figure 25. Abnormal Over-Current Protection

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

4.3 Over-Voltage Protection (OVP): If the secondary-

side feedback circuit malfunctions or a solder defect causes an opening in the feedback path, the current through the opto-coupler transistor becomes almost zero. Then V

climbs up in a similar manner to the

FB

overload situation, forcing the preset maximum current to be supplied to the SMPS until the overload protection triggers. Because more energy than required is provided to the output, the output voltage may exceed the rated voltage before the overload protection triggers, resulting in the breakdown of the devices in the secondary side. To prevent this situation, an OVP circuit is employed. In general, the peak voltage of the sync signal is proportional to the output voltage and the FSQ-series uses a sync signal instead of directly monitoring the output voltage. If the sync signal exceeds 6V, an OVP is triggered, shutting down the SMPS. To avoid undesired triggering of OVP during normal operation, the peak voltage of the sync signal should be designed below 6V.

4.4 Thermal Shutdown (TSD): The SenseFET and the

control IC are built in one package. This makes it easy for the control IC to detect the abnormal over temperature of the SenseFET. If the temperature exceeds ~150°C, the thermal shutdown triggers.

5. Soft-Start: An internal soft-start circuit increases

PWM comparator inverting input voltage with the SenseFET current slowly after it starts up. The typical soft-start time is 15ms. The pulsewidth to the power switching device is progressively increased to establish the correct working conditions for transformers, inductors, and capacitors. The voltage on the output capacitors is progressively increased with the intention of smoothly establishing the required output voltage. This helps prevent transformer saturation and reduces stress on the secondary diode during startup.

6. Burst Operation: To minimize power dissipation in

Standby Mode, the FPS enters Burst-Mode operation. As the load decreases, the feedback voltage decreases. As shown in Figure 26, the device automatically enters Burst Mode when the feedback voltage drops below V

(350mV). At this point, switching stops and the

BURL

output voltages start to drop at a rate dependent on standby current load. This causes the feedback voltage to rise. Once it passes V

(550mV), switching

BURH

resumes. The feedback voltage then falls and the process repeats. Burst Mode alternately enables and disables switching of the power SenseFET, reducing switching loss in Standby Mode.

V

O

set

V

O

V

FB

0.55V

0.35V

I

DS

V

DS

time

t4

FSQ0365RN Rev.00

Switching

disabled

t1

t2 t3

Switching

disabled

Figure 26. Waveforms of Burst Operation

7. Switching Frequency Limit

: To minimize switching loss and Electromagnetic Interference (EMI), the MOSFET turns on when the drain voltage reaches its minimum value in valley switching operation. However, this causes switching frequency to increases at light load conditions. As the load decreases, the peak drain current diminishes and the switching frequency increases. This results in severe switching losses at light-load condition, as well as intermittent switching and audible noise. Because of these problems, the valley switching converter topology has limitations in a wide range of applications.

To overcome this problem, FSQ-series employs a frequency-limit function, as shown in Figure 27 and Figure 28. Once the SenseFET is turned on, the next turn-on is prohibited during the blanking time (t

). After

B

the blanking time, the controller finds the valley within the detection time window (t

) and turns on the

W

MOSFET, as shown in Figure 27 and Figure 28 (cases A, B, and C). If no valley is found during t SenseFET is forced to turn on at the end of t

, the internal

W

(case D).

W

Therefore, FSQ devices have a minimum switching frequency of 55kHz and a maximum switching frequency of 67kHz, as shown in Figure 28.

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

I

DS

I

DS

t

=15s

B

I

DS

max

t

s

tB=15s

t

tB=15s

t

=18s

s

When the resonant period is 2s

I

DS

A

I

DS

B

67kHz

59kHz 55kHz

Burst mode

FSQ0365RN Rev. 00

A

C

B

Constant frequency

D

P

O

Figure 28. Switching Frequency Range

I

DS

C

t

s

I

=15s

t

B

DS

tW=3s

max

=18s

t

s

I

DS

D

FSQ0365RN Rev. 00

Figure 27. Valley Switching with Limited Frequency

Typical Application Circuit of FSQ0365RN

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Application FPS Device

Input Voltage

Range

Rated Output Power

Output Voltage

(Maximum Current)

5.1V (1.0A)

DVD Player

Power Supply

FSQ0365RN 85-265V

19W

AC

3.4V (1.0A)

12V (0.4A)

16V (0.3A)

Features

 High efficiency ( >77% at universal input)  Low standby mode power consumption (<1W at 230V

input and 0.5W load)

AC

 Reduce EMI noise through Valley Switching operation  Enhanced system reliability through various protection functions  Internal soft-start: 15ms

Key Design Notes

 The delay time for overload protection is designed to be about 30ms with C107 of 47nF. If faster/slower triggering

of OLP is required, C107 can be changed to a smaller/larger value (eg. 100nF for 60ms).

 The input voltage of V

voltage can be adjusted.

 The SMD-type 100nF capacitor must be placed as close as possible to V

pulsating noises and to improved surge immunity

must be higher than -0.3V. By proper voltage sharing by R106 & R107 resistors, the input

sync

pin to avoid malfunction by abrupt

CC

.

Schematic

RT101

5D-9

2

BD101

1

Bridge

Diode

4

C102

100nF,275V

AC

LF101

40mH

C101 100nF 275V

AC

TNR

10D471K

AC IN

3

C103 33F 400V

F101

FUSE

R105

100kΩ

FSQ0365RN

5

V

str

4

Sync

3

FB

C104 10nF 630V

R108

62Ω

IC101

GND

Drain Drain Drain

V

1

1N4746A

8 7 6

2

cc

ZD101

D101

1N 4007

C106

100nF

SMD

C107 22F

50V

1N 4004

C110 33pF

50V

D102

R103

5Ω

R104 12kΩ

6.2kΩ

R106

R107

C105 47nF

50V

R102 56kΩ

Figure 29. Demo Circuit of FSQ0365RN

EER2828

1

2

3

4

5

1N4148

D103

C302

3.3nF

IC202

FOD817A

T101

11

10

12

6

9

8

UF4003

IC201 KA431

D201

UF4003

C210 47pF

D202

D203

SB360

D204

SB360

R201 510Ω

C209 47pF

R202

1kΩ

C201

470F

35V

470F

R204

20kΩ

C203

35V

L201

L202

L203

C205

1000F

10V

L204

C207

1000F

10V

C209

100nF

R205

6kΩ

C202

470F

35V

C204

470F

35V

R203

6.2kΩ

16V, 0.3A

12V, 0.4A

5.1V, 1A

C206

1000F

10V

C208

1000F

10V

FSQ0365RN Rev:00

3.4V, 1A

Transformer

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Np/2

N

EER2828

1

2

3

4

a

5

12

11

10

9

8

7

6

Figure 30. Transformer Schematic Diagram of FSQ0365RN

Table 1. Winding Specification

No.

Np/2

Pin (sf)

2 0.25

3

Insulation: Polyester Tape t = 0.050mm, 2-Layer

N

3.4V

8 0.33

9

Insulation: Polyester Tape t = 0.050mm, 2-Layer

N5V

9 0.33

6

Insulation: Polyester Tape t = 0.050mm, 2-Layer

Na

5 0.25

4

Insulation: Polyester Tape t = 0.050mm, 2-Layer

N

12V

12 0.33

10

Insulation: Polyester Tape t = 0.050mm, 3-Layer

N

16V

12 0.33

11

Insulation: Polyester Tape t = 0.050mm, 2-Layer

Np/2

1 0.25

2

Insulation: Polyester Tape t = 0.050mm, 2-Layer

Wire Turns Winding Method

N



16V

12V

3.4V

5.1V

x 1

x 2

x 1

x 3

x 1

Np/2 N

16V

N

12V

N

a

N

6mm 3mm

N

Np/2

5.1V

3.4V

FSQ0365RN Rev: 00

50 Center Solenoid Winding

4 Center Solenoid Winding

2 Center Solenoid Winding

16 Center Solenoid Winding

14 Center Solenoid Winding

18 Center Solenoid Winding

50 Center Solenoid Winding

Table 2. Electrical Characteristics

Pin Specification Remarks

Inductance 1 - 3 1.4mH ± 10% 100kHz, 1V

Leakage 1 - 3 25µH Maximum Short All Other Pins

Core & Bobbin

 Core: EER2828 (Ae=86.66mm

2

)

 Bobbin: EER2828

Table 3. Demo Board Part List

Part Value Note Part Value Note

Resistor Inductor

R102 56k 1W L201 10µH

R103 5 1/2W L202 10µH

R104 12k 1/4W L203 4.9µH

R105 100k 1/4W L204 4.9µH

R106 6.2k 1/4W

R107 6.2k 1/4W D101 IN4007

R108 62 1W D102 IN4004

R201 510 1/4W ZD101 1N4746A

R202 1k 1/4W D103 1N4148

R203 6.2k 1/4W D201 UF4003

R204 20k 1/4W D202 UF4003

R205 6k 1/4W D203 SB360

Capacitor

D204 SB360

C101 100nF/275VAC Box Capacitor

C102 100nF/275VAC Box Capacitor

C103 33µF/400V Electrolytic Capacitor IC101 FSQ0365RN FPS™

C104 10nF/630V Film Capacitor IC201 KA431 (TL431) Voltage reference

C105 47nF/50V Mono Capacitor IC202 FOD817A Opto-coupler

C106 100nF/50V SMD (1206)

C107 22µF/50V Electrolytic Capacitor Fuse 2A/250V

C110 33pF/50V Ceramic Capacitor

C201 470µF/35V Electrolytic Capacitor RT101 5D-9

C202 470µF/35V Electrolytic Capacitor

C203 470µF/35V Electrolytic Capacitor BD101 2KBP06M2N257 Bridge Diode

C204 470µF/35V Electrolytic Capacitor

C205 1000µF/10V Electrolytic Capacitor LF101 40mH

C206 1000µF/10V Electrolytic Capacitor

C207 1000µF/10V Electrolytic Capacitor T101

C208 1000µF/10V Electrolytic Capacitor

C209 100nF /50V Ceramic Capacitor TNR 10D471K

Diode

IC

Fuse

NTC

Bridge Diode

Line Filter

Transformer

Varistor

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Package Dimensions

A

(.092) [Ø2.337]

.400

10.15

.373

9.46

[

.036 [0.9 TYP]

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

]

PIN #1

.021

0.53

.015

0.37

[

.001[.025]

NOTES:

A. CONFORMS TO JEDEC REGISTRATION MS-001, VARIATIONS BA B. CONTROLING DIMENSIONS ARE IN INCHES REFERENCE DIMENSIONS ARE IN MILLIMETERS C. DOES NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCHES OR 0.25MM. D. DOES NOT INCLUDE DAMBAR PROTRUSIONS. DAMBAR PROTRUSIONS SHALL NOT EXCEED .010 INCHES OR 0.25MM. E. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994.

[5.33]

(.032) [R0.813]

PIN #1

.310±.010 [7.87±0.25]

7° TYP

TOP VIEW OPTION 2

.060 MAX

[1.52]

+.005

.010

-.000

.300

[7.62]

.430 MAX

[10.92]

0.254

[

+0.127

-0.000

]

.250±.005 [6.35±0.13]

TOP VIEW

OPTION 1

.070 .045

7° TYP

C

]

C

.100

[2.54]

B

1.78

1.14

[

]

.130±.005 [3.3±0.13]

.015 MIN

[0.38]

.140

3.55

[

.125

3.17

.210 MAX

]

N08EREVG

Figure 31. 8-Lead , Dual Inline Package (DIP)

Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products.

Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:

http://www.fairchildsemi.com/packaging/

.

Package Dimensions (Continued)

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

MKT-MLSOP08ArevA

Figure 32. 8-Lead , MLSOP

Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products.

Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:

http://www.fairchildsemi.com/packaging/

.

FSQ0365/0265/0165/321 — Green Mode Fairchild Power Switch (FPS™) for Valley Switching Converter

Fairchild FSQ0265RN service manual

Specifications and Main Features

Frequently Asked Questions

User Manual