Fairchild FSQ100 service manual

FSQ100 Green Mode Fairchild Power Switch (FPS™)

FSQ100 — Green Mode Fairchild Power Switch (FPS

March 2011

Features

 Internal Avalanche-Rugged SenseFET  Precision Fixed Operating Frequency: 67KHz  Burst-Mode Operation  Internal Startup Circuit  Pulse-by-Pulse Current Limiting  Over-Voltage Protection (OVP)  Overload Protection (OLP)  Internal Thermal Shutdown Function (TSD)  Auto-Restart Mode  Under-Voltage Lockout (UVLO) with Hysteresis  Built-in Soft-Start  Secondary-Side Regulation

Applications

 Charger & Adapter for Mobile Phone, PDA, MP3  Auxiliary Power for White Goods, PC, C-TV, Monitor

Related Application Notes

Description

The FSQ100 consists of an integrated Pulse Width Modulator (PWM) and SenseFET, specifically designed for high-performance, off-line, Switch-Mode Power Supplies (SMPS) with minimal external components. This device is an integrated high-voltage power switching regulator that combines a VDMOS SenseFET with a voltage mode PWM control block. The integrated PWM controller features include a fixed oscillator, Under-Voltage Lockout (UVLO) protection, Leading Edge Blanking (LEB), an optimized gate turn-on/turn-off driver, Thermal Shutdown (TSD) protection, and temperature-compensated precision-current sources for loop compensation and fault protection circuitry.

When compared to a discrete MOSFET and controller or RCC solution, the FSQ100 device reduces total component count and design size and weight, while increasing efficiency, productivity, and system reliability. This device provides a basic platform well suited for cost-effective flyback converters.

TM

)

AN-4137 — Design Guidelines for Off-line Flyback



Converters using FPS™

 AN-4141 — Troubleshooting and Design Tips for

Fairchild Power Switch (FPS™) Flyback Applications

 AN-4147 — Design Guidelines for RCD Snubber of

Flyback

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

Converters using FPS™

 AN-4138 — Design Considerations for Battery

Charger Using Green Mode Fairchild Power Switch (FPS™)

Ordering Information

Product Number Package Marking Code BV

FSQ100 8-DIP Q100 650V 67KHz

FPS™ is a trademark of Fairchild Semiconductor Corporation.

f

DSS

R

OSC

DS(ON)

16Ω

A

f

A

r

Typical Application

FSQ100 — Green Mode Fairchild Power Switch (FPS

C

IN

V

STR

Drain

PWM

DC

OUT

V

FB

GND

CC

Figure 1. Typical Flyback Application

Table 1. Output Power Table

Product

230VAC ±15%

FSQ100 13W 8W

Notes:

1. Maximum practical continuous power in an open-frame design with sufficient drain pattern as a heat sinker, at 50C ambient.

2. 230VAC or 100/115VAC with doubler.

(2)

Open Frame

(1)

85~265V

AC

Internal Block Diagram

V

STR

V

2

CC

OSC

PWM

Internal

Bias

9/7V

Vck

SRQ

UVLO

I

delay

fb

µA

40

5

V

FB

3

0

Voltage

Re

L

H

5

DR IVER

D

6,7,8

ain

SFET

TM

)

S/ S

15ms

V

/

BURL

V

BURH

C

N

4

Reset

V

Min.20V

OV P

BURST

LEB

OLP

SD

TSD

SRQ

/R

I

LIM

R

V

th

sense

1

GND

Figure 2. Functional Block Diagram

r

Pin Assignments

FSQ100 — Green Mode Fairchild Power Switch (FPS

1

2

V

CC

V

3

FB

45

NC

Drain

8GND

ain

D

7

ain

6

D

V

STR

Figure 3. Pin Configuration (Top View)

Pin Definitions

Pin # Name Description

1 GND

2 VCC

3 VFB

4 NC

5 V

STR

6,7,8 Drain

Ground. SenseFET source terminal on primary-side and internal control ground. Positive Supply Voltage Input. Although connected to an auxiliary transformer winding,

current is supplied from pin 5 (V V

reaches the UVLO upper threshold (9V), the internal startup switch opens and device power

CC

) via an internal switch during startup (see Figure 2). When

STR

is supplied via the auxiliary transformer winding.

Feedback. Inverting input to the PWM comparator with its normal input level lies between 0.5V

and 2.5V. It has a 0.4mA current source connected internally, while a capacitor and optocoupler are typically connected externally. A feedback voltage of 4.5V triggers overload protection (OLP). There is a time delay while charging external capacitor C using an internal 5µA current source. This time delay prevents false triggering under transient conditions, but still allows the protection mechanism to operate in true overload conditions.

No Connection. Startup. This pin connects directly 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 9V, the internal switch stops charging the capacitor.

CC

SenseFET Drain. 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.

TM

)

from 3V to 4.5V

fb

FSQ100 — Green Mode Fairchild Power Switch (FPS

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 Value Unit

V

Drain Pin Voltage 650 V

DRAIN

V

VSTR Pin Voltage 650 V

STR

VDG Drain-Gate Voltage 650 V

VGS Gate-Source Voltage

VCC Supply Voltage 20 V

VFB Feedback Voltage Range -0.3 to V

PD Total Power Dissipation 1.40 W

TJ Operating Junction Temperature Internally limited °C

TA Operating Ambient Temperature -25 to +85 °C

T

Storage Temperature -55 to +150 °C

STG

Notes:

1. Repetitive rating: Pulse width is limited by maximum junction temperature.

2. L = 24mH, starting T

= 25C.

J

= 25°C, unless otherwise specified.

A

±20

STOP

V

TM

)

Thermal Impedance

TA = 25°C, unless otherwise specified. All items are tested with the JEDEC standards JESD 51-2 and 51-10 (DIP).

Symbol Parameter Value Unit

θJA Junction-to-Ambient Thermal Impedance

θJC Junction-to-Case Thermal Impedance

Notes:

3. Free-standing with no heatsink; without copper clad. Measurement condition; just before junction temperature TJ enters into OTP.

4. Measured on the DRAIN pin close to plastic interface.

(3)

88.84 °C/W

(4)

13.94 °C/W

FSQ100 — Green Mode Fairchild Power Switch (FPS

Electrical Characteristics

TA = 25°C, unless otherwise specified.

Symbol Parameter Conditions Min. Typ. Max. Unit

SenseFET Section

I

Zero-Gate-Voltage Drain Current

DSS

R

Drain-Source On-State Resistance

DS(ON)

gfs Forward Trans-Conductance VDS=50V, ID=0.5A 1.0 1.3 S

C

Input Capacitance

ISS

Output Capacitance 18

OSS

C

Reverse Transfer Capacitance 3.8

RSS

Control Section

f

Switching Frequency 61 67 73 kHz

OSC

Δf

Switching Frequency Variation

OSC

D

Maximum Duty Cycle 60 67 74 %

MAX

V

START

V

STOP

UVLO Threshold Voltage

V

(6)

-25°C ≤ TA ≤ 85°C ±5 ±10 %

IFB Feedback Source Current 0V ≤ VFB ≤ 3V 0.35 0.40 0.45 mA

t

Internal Soft Start Time 10 15 20 ms

S/S

Burst Mode Section

V

BURH

V

0.45 0.55 0.65 V

BURL

V

BUR(HYS)

Burst Mode Voltage

Hysteresis 150 mV

Protection Section

I

Peak Current Limit 0.475 0.550 0.650 A

LIM

TSD Thermal Shutdown Temperature

(7)

VSD Shutdown Feedback Voltage 4.0 4.5 5.0 V

V

Over-Voltage Protection 20 V

OVP

I

Shutdown Delay Current 3V ≤ VFB ≤ VSD 4 5 6 µA

DELAY

Total Device Section

IOP Operating Supply Current

(8)

V

ICH Startup Charging Current VCC=0V , V

Notes:

5. Pulse test: Pulse width ≤ 300µs, duty ≤ 2%.

6. These parameters, although guaranteed, are tested in EDS (wafer test) process.

7. These parameters, although guaranteed, are not 100% tested in production.

8. Control part only.

VDS=650V, VGS=0V 25

VDS=520V, VGS=0V, TC=125C

(5)

VGS=10V, ID=0.5A 16 22 Ω

200

µA

162

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

V

GS

pF C

VFB=GND 8 9 10 V

=GND 6 7 8 V

FB

TJ=25°C

0.6 0.7 0.8 V

125 145 °C

≤ 16V 1.5 3.0 mA

CC

=50V 450 550 650 µA

STR

TM

)

Typical Performance Characteristics

These characteristic graphs are normalized at T

= 25°C.

A

FSQ100 — Green Mode Fairchild Power Switch (FPS

1.15

1.10

1.05

1.00

OVP

V

0.95

0.90

0.85

-50 0 50 100 150

Temperature [°C]

Figure 4. Over-Voltage Protection (V

1.15

1.10

1.05

1.00

OP

) vs. TA Figure 5. Operating Supply Current (IOP) vs. TA

OVP

I

0.95

0.90

0.85

-50 0 50 100 150

Temperature [°C]

1.15

1.10

1.05

1.00

STAART

V

0.95

0.90

0.85

-50 0 50 100 150

1.15

1.10

1.05

1.00

STOP

V

0.95

0.90

0.85

-50 0 50 100 150

TM

)

Temperature [°C]

Figure 6. Start Threshold Voltage (V

) vs. TA Figure 7. Stop Threshold Voltage (V

START

Temperature [°C]

STOP

) vs. TA

1.15

1.10

1.05

1.00

OSC

f

0.95

0.90

0.85

-50 0 50 100 150

Temperature [°C]

Figure 8. Operating Frequency (f

1.15

1.10

1.05

1.00

MAX

D

0.95

0.90

0.85

-50 0 50 100 150

Temperature [°C]

) vs. TA Figure 9. Maximum Duty Cycle (D

OSC

) vs. TA

MAX

Typical Performance Characteristics (Continued)

These characteristic graphs are normalized at T

= 25°C.

A

FSQ100 — Green Mode Fairchild Power Switch (FPS

1.15

1.10

1.05

1.00

LIM

I

0.95

0.90

0.85

-50 0 50 100 150

Temperature [°C]

Figure 10. Peak Current Limit (I

1.15

1.10

1.05

1.00

FB

) vs. TA Figure 11. Feedback Source Current (IFB) vs. TA

LIM

I

0.95

0.90

0.85

-50 0 50 100 150

Temperature [°C]

1.15

1.10

1.05

1.00

DELAY

I

0.95

0.90

0.85

-50 0 50 100 150

1.15

1.10

1.05

SD

1.00

V

0.95

0.90

0.85

-50 0 50 100 150

TM

)

Temperature [°C]

Figure 12. Shutdown Delay Current (I

) vs. TA Figure 13. Shutdown Feedback Voltage (VSD) vs. TA

DELAY

Temperature [°C]

R

f

A

r

w

Functional Description

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

source supplies the internal bias and charges the external V V

reaches 9V, the device starts switching and the

CC

internal high-voltage current source stops charging the capacitor. The device is in normal operation provided V

does not drop below 7V. After startup, the bias is

CC

supplied from the auxiliary transformer winding.

Calculating the V design with the FSQ100. At initial startup, the maximum value of start operating current I which supplies current to UVLO and V charging current I – 100µA. After V the bias winding supplies V When the bias winding voltage is not sufficient, the V level decreases to the UVLO stop voltage and the internal current source is activated again to charge the V

capacitor. To prevent this VCC fluctuation

CC

(charging/discharging), the V chosen to have a value between 10µF and 47µF.

V

capacitor, as shown in Figure 14. When

CC

VIN,dc

I

STR

Vstr

V

CC

L

H

9V/ 7V

Figure 14. Internal Startup Circuit

capacitor is an important step to

CC

is about 100µA,

START

of the V

VCC

reaches the UVLO start voltage, only

CC

VIN,dc

I

=I

- I

Vc c

STR

ST

R T

I

= I

-I

Vcc

STR

START

V

CC

capacitor is equal to I

CC

current to the device.

CC

I

ST

R T

U VLO

V

REF

capacitor should be

I

STR

V

ST

J-F ET

re

blocks. The

STR

CC

When the shunt regulator reference pin voltage exceeds the internal reference voltage of 2.5V, the opto-coupler LED current increases, the feedback voltage V pulled down, and it reduces the duty cycle. This happens when the input voltage increases or the output load decreases.

V

CC

5µA

KA431

V

fb

4

+

C

fb

V

fb

V

SD

V

O

OSC

V

ref

400µA

R

OLP

Gate

driver

Figure 16. PWM and Feedback Circuit

3. Leading Edge Blanking (LEB): At the instant the

internal SenseFET is turned on, the primary-side capacitance and secondary-side rectifier diode reverse recovery typically causes a high-current spike through the SenseFET. Excessive voltage across the R resistor lead to incorrect pulse-by-pulse current limit protection. To avoid this, a leading edge blanking (LEB) circuit disables pulse-by-pulse current-limit protection block for a fixed time (t

) after the SenseFET turns on.

LEB

4. Protection Circuit: The FSQ100 has protective

functions, such as overload protection (OLP), over voltage protection (OVP), under-voltage lockout (UVLO), and thermal shutdown (TSD). Because these protection circuits are fully integrated inside the IC without external components, reliability is improved without increasing costs. Once a fault condition occurs, switching is terminated and the SenseFET remains off. This causes V

to fall. When VCC reaches the UVLO stop voltage

CC

V

(7V), the protection is reset and the internal high-

STOP

voltage current source charges the V V

pin. When VCC reaches the UVLO start voltage

STR

V

(9V), the device resumes normal operation. In

START

capacitor via the

CC

this manner, the auto-restart can alternately enable and disable the switching of the power SenseFET until the fault condition is eliminated.

FB

SENSE

FSQ100 — Green Mode Fairchild Power Switch (FPS

is

TM

)

V

START

V

STOP

Figure 15. Charging V

UV LO

V

must not d

CC

belo

Biaswinding

voltage

Capacitor through Vstr

CC

op

V

STOP

t

2. Feedback Control: The FSQ100 is a voltage mode

controlled device, as shown in Figure 16. Usually, an

5 µA 4 00 µ A

V

fb

4

C

fb

RESET

Figure 17. Protection Block

OSC

+

-

R

OLP

4.5 V TSD

SRQ

A/R

GATE

DRIVER

OLP, TSD

Protection Block

opto-coupler and shunt regulator, like KA431 are used to implement the feedback network. The feedback voltage is compared with an internally generated sawtooth waveform. This directly controls the duty cycle.

4.1 Overload Protection (OLP): Overload is defined as

the load current exceeding a pre-set level due to an unexpected event. In this situation, the protection circuit should be activated to protect the SMPS. However, even when the SMPS is operating normally, the over load protection (OLP) circuit can be activated during the load transition. To avoid this undesired operation, the OLP circuit is designed to be activated after a specified time to determine whether it is a transient situation or a true overload situation. If the output consumes more than the maximum power determined by I voltage (V

) decreases below its rating voltage. This

O

, the output

LIM

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 3V, the feedback input diode is blocked and the 5µA current source (I up to V

. In this condition, VFB increases until it reaches

CC

) starts to charge CFB slowly

DELAY

4.5V, when the switching operation is terminated, as shown in Figure 18. The shutdown delay time is the time required to charge C

from 3V to 4.5V with a 5µA

FB

current source.

V

FB

Overload Protection

4.5V

Drain current

0.55A

2.14ms

0.31A

7steps

t

Figure 19. Internal Soft-Start

6. Burst Operation: To minimize the power dissipation

in standby mode, the FSQ100 enters burst-mode operation. As the load decreases, the feedback voltage decreases. The device automatically enters burst mode when the feedback voltage drops below V

BURL

(0.55V). At this point, switching stops and the output voltages start to drop. This causes the feedback voltage to rise. Once is passes V

(0.70V), switching starts again.

BURH

The feedback voltage falls and the process repeats. Burst-mode operation alternately enables and disables switching of the power MOSFET to reduce the switching loss in standby mode.

OSC

FSQ100 — Green Mode Fairchild Power Switch (FPS

TM

)

3V

DELAY

t

)-V( t

)) /

2

I

1

DELAY

t

2

VtVVtVAI

5.4)(,3)(,5;

===

21

=Cfb×(V(

t

12

t

1

tVtV

)()(

−

I

DELAY

12

Cfbt

=µ

12

Figure 18. Overload Protection (OLP)

4.2 Thermal Shutdown (TSD): The SenseFET and the

control IC are integrated, making it easier for the control IC to detect the temperature of the SenseFET. When the temperature exceeds approximately 145C, thermal shutdown is activated.

5. Soft-Start: The FPS has an internal soft-start circuit

that slowly increases the feedback voltage, together with the SenseFET current, right after it starts. The typical soft-start time is 15ms, as shown in Figure 19, where progressive increment of the SenseFET current is allowed during the startup phase. Soft-start circuit progressively increases current limits to establish proper working conditions for transformers, inductors, capacitors, and switching devices. It also helps to prevent transformer saturation and reduces the stress on the secondary diode.

5µA 400µA

4

V

fb

Figure 20. Burst Operation Block

V

O

set

V

O

V

FB

0. 70V

0.55V

I

ds

V

ds

Figure 21. Burst Operation Function

SRQ

0.7 0 V

/0.55V

Burst Operati on Bloc k

GATE

DRIVER

on /off

t

Application Tips

1. Methods of Reducing Audible Noise

Switching mode power converters have electronic and magnetic components that generate audible noise when the operating frequency is in the range of 20~20,000Hz. Even though they operate above 20kHz, they can make noise, depending on the load condition. Designers can employ several methods to reduce noise.

Glue or Varnish

The most common method involves using glue or varnish to tighten magnetic components. The motion of core, bobbin and coil, and the chattering or magnetostriction of core can cause the transformer to produce audible noise. The use of rigid glue and varnish helps reduce the transformer noise, but can crack the core. This is because sudden changes in the ambient temperature cause the core and the glue to expand or shrink in a different ratio.

Ceramic Capacitor

Using a film capacitor instead of a ceramic capacitor as a snubber capacitor is another noise-reduction solution. Some dielectric materials show a piezoelectric effect, depending on the electric field intensity. Hence, a snubber capacitor becomes one of the most significant sources of audible noise. It is possible to use a Zener clamp circuit instead of an RCD snubber for higher efficiency as and lower audible noise.

Adjusting Sound Frequency

Moving the fundamental frequency of noise out of 2~4kHz range is the third method. Generally, humans are more sensitive to noise in the range of 2~4kHz. When the fundamental frequency of noise is located in this range, the noise is perceived as louder, although the noise intensity level is identical (refer to Figure 22

Equal Loudness Curves).

When FPS acts in burst mode and the burst operation is suspected to be a source of noise, this method may be helpful. If the frequency of burst-mode operation lies in the range of 2~4 kHz, adjusting the feedback loop can shift the burst operation frequency. To reduce the burst operation frequency, increase a feedback gain capacitor (C

), opto-coupler supply resistor (RD), and feedback

F

capacitor (C (R

), as shown in Figure 23.

F

); and decrease a feedback gain resistor

B

Figure 22. Equal Loudness Curves

Figure 23. Typical Feedback Network of FPS™

2. Reference Materials

AN-4134 — Design Guidelines for Off-line Forward Converters using FPS™

AN-4137 — Design Guidelines for Off-line Flyback Converters using FPS™

AN-4138 — Design Considerations for Battery Charger Using Green Mode 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™) Flyback Applications

AN-4147 — Design Guidelines for RCD Snubber of Flyback

AN-4148 — Audible Noise Reduction Techniques for FPS™Applications

FSQ100 — Green Mode Fairchild Power Switch (FPS

TM

)

Physical Dimensions

0.400

0.355

10.160

9.017

[

FSQ100 Green Mode Fairchild Power Switch (FPS

]

PIN 1 INDICATOR

HALF LEAD 4X

0.005 [0.126]

SEATING PLANE

MIN 0.015 [0.381]

0.100 [2.540]

0.022

0.014

[

0.562

0.358

85

0.280

7.112

0.240

6.096

[

41

FULL LEAD 4X

0.005 [0.126] MIN

MAX 0.210 [5.334]

0.150

0.115

C

0.045

0.030

[

]

0.10 C

Figure 24. 8-Pin Dual Inline Package (DIP)

0.070

1.778

0.045

1.143

[

NOTES:

A) THIS PACKAGE CONFORMS TO

JEDEC MS-001 VARIATION BA

B) CONTROLING DIMS ARE IN INCHES

C) DIMENSIONS ARE EXCLUSIVE OF BURRS,

MOLD FLASH, AND TIE BAR EXTRUSIONS.

D) DIMENSIONS AND TOLERANCES PER ASME

Y14.5M -1982

E) DRAWING FILENAME AND REVSION: MKT-N08MREV1.

]

0.195

0.115

[

1.144

0.763

4X

]

3.811

2.922

]

[

4X

4.965

2.933

]

0.325

8.263

0.300

7.628

[

]

0.015 [0.389] GAGE PLANE

TM

)

0.300 [7.618]

0.430 [10.922] MAX

FSQ100 Green Mode Fairchild Power Switch (FPS

TM

)

Fairchild FSQ100 service manual

Specifications and Main Features

Frequently Asked Questions

User Manual