Datasheet FSFR1700US Specification

May 2010

FSFR-US Series — Fairchild Power Switch (FPS™)

for Half-Bridge Resonant Converters

FSFR-US Series — Fairchild Power Switch (FPS

Features

 Variable Frequency Control with 50% Duty Cycle

for Half-Bridge Resonant Converter Topology

 High Efficiency through Zero Voltage Switching (ZVS)  Internal UniFET™s with Fast-Recovery Type

Body Diode

 Fixed Dead Time (350ns) Optimized for MOSFETs  Up to 300kHz Operating Frequency  Auto-Restart Operation for All Protections with An

External LV

CC

 Protection Functions: Over-Voltage Protection

(OVP), Over-Current Protection (OCP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD)

Applications

 PDP and LCD TVs  Desktop PCs and Servers  Adapters  Telecom Power Supplies

Description

The FSFR-US series are a highly integrated power switches designed for high-efficiency half-bridge resonant converters. Offering everything necessary to build a reliable and robust resonant converter, the FSFRUS series simplifies designs and improves productivity, while improving performance. The FSFR-US series combines power MOSFETs with fast-recovery type body diodes, a high-side gate-drive circuit, an accurate current controlled oscillator, frequency limit circuit, soft-start, and built-in protection functions. The high-side gate-drive circuit has a common-mode noise cancellation capability, which guarantees stable operation with excellent noise immunity. The fast-recovery body diode of the MOSFETs improves reliability against abnormal operation conditions, while minimizing the effect of the reverse recovery. Using the zero-voltage-switching (ZVS) technique dramatically reduces the switching losses and efficiency is significantly improved. The ZVS also reduces the switching noise noticeably, which allows a small-sized Electromagnetic Interference (EMI) filter.

The FSFR-US series can be applied to various resonant converter topologies such as series resonant, parallel resonant, and LLC resonant converters.

Related Resources

AN4151 — Half-bridge LLC Resonant Converter Design using FSFR-Series Fairchild Power Switch (FPSTM)

™

) for Half-Bridge Resonant Converter

Ordering Information

Operating

Part Number Package

FSFR2100US

FSFR1800US

FSFR1700US

FSFR2100USL

FSFR1800USL

FSFR1700USL

Notes:

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

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

9-SIP

L-Forming

Junction

Temperature

-40 to +130°C

R

DS(ON_MAX)

0.51Ω

0.95Ω

1.25Ω

0.51Ω

0.95Ω

1.25Ω

Maximum Output Power

without Heatsink

(V

=350~400V)

IN

180W 400W

120W 260W

100W 200W

180W 400W

120W 260W

100W 200W

(1,2)

Maximum Output

Power with Heatsink

(VIN=350~400V)

(1,2)

Application Circuit Diagram

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter)

Block Diagram

Figure 2. Internal Block Diagram

Pin Configuration

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Figure 3. Package Diagram

Pin Definitions

Pin # Name Description

1 VDL This is the drain of the high-side MOSFET, typically connected to the input DC link voltage.

This pin is for discharging the external soft-start capacitor when any protections are

2 AR

3 RT

4 CS

5 SG This pin is the control ground.

6 PG This pin is the power ground. This pin is connected to the source of the low-side MOSFET.

7 LVCC This pin is the supply voltage of the control IC.

8 NC No connection.

9 HVCC This is the supply voltage of the high-side gate-drive circuit IC.

10 V

CTR

triggered. When the voltage of this pin drops to 0.2, all protections are reset and the controller starts to operate again.

This pin programs the switching frequency. Typically, an opto-coupler is connected to control the switching frequency for the output voltage regulation.

This pin senses the current flowing through the low-side MOSFET. Typically, negative voltage is applied on this pin.

This is the drain of the low-side MOSFET. Typically, a transformer is connected to this pin.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant 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

=25°C unless otherwise specified.

A

VDS

Maximum Drain-to-Source Voltage (V

DL-VCTR

and V

CTR

-PG)

500 V

LVCC Low-Side Supply Voltage -0.3 25.0 V

HVCC to V

High-Side VCC Pin to Low-Side Drain Voltage -0.3 25.0 V

CTR

HVCC High-Side Floating Supply Voltage -0.3 525.0 V

VAR Auto-Restart Pin Input Voltage -0.3 LVCC V

VCS Current Sense (CS) Pin Input Voltage -5.0 1.0 V

VRT R

dV

/dt Allowable Low-Side MOSFET Drain Voltage Slew Rate 50 V/ns

CTR

Pin Input Voltage -0.3 5.0 V

T

FSFR2100US/L 12.0

PD Total Power Dissipation

(3)

FSFR1700US/L 11.6

TJ

T

STG

Maximum Junction Temperature

Recommended Operating Junction Temperature

Storage Temperature Range -55 +150

(4)

+150

(4)

-40 +130

Notes:

3. Per MOSFET when both MOSFETs are conducting.

4. The maximum value of the recommended operating junction temperature is limited by thermal shutdown.

W FSFR1800US/L 11.7

°C

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Absolute Maximum Ratings (Continued)

Symbol Parameter Min. Max. Unit

MOSFET Section

V

DGR

Drain Gate Voltage (RGS=1MΩ)

VGS Gate Source (GND) Voltage ±30 V

FSFR2100US/L 32

IDM Drain Current Pulsed

(5)

FSFR1700US/L 20

=25°C

T

FSFR2100US/L

C

TC=100°C

=25°C

T

ID Continuous Drain Current

FSFR1800US/L

C

TC=100°C

T

=25°C

FSFR1700US/L

C

TC=100°C

Package Section

Torque Recommended Screw Torque 5~7 kgf·cm

Notes:

5. Pulse width is limited by maximum junction temperature.

500 V

A FSFR1800US/L 23

10.5

6.5

7.0

4.5

A

6.0

3.9

Thermal Impedance

TA=25°C unless otherwise specified.

Symbol Parameter Value Unit

FSFR2100US/L

θJC

Junction-to-Case Center Thermal Impedance (Both MOSFETs Conducting)

FSFR1800US/L

FSFR1700US/L

10.44

10.68

10.79

ºC/W

Electrical Characteristics

TA=25°C unless otherwise specified.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Symbol Parameter Test Conditions

Specifications

Min. Typ. Max.

MOSFET Section

BV

Drain-to-Source Breakdown Voltage

DSS

R

On-State Resistance

DS(ON)

FSFR2100US/L

FSFR1800US/L

=200μA, TA=25°C

I

D

ID=200μA, TA=125°C

V

=10V, ID=6.0A 0.41 0.51

GS

V

=10V, ID=3.0A 0.77 0.95

GS

500

540

FSFR1700US/L VGS=10V, ID=2.0A 1.00 1.25

=0V, I

V

FSFR2100US/L

t

rr

Body Diode Reverse Recovery Time

(6)

FSFR1800US/L

FSFR1700US/L

dI

V dI

GS

Diode

GS

Diode

GS

Diode

=0V, I

/dt=100A/μs

Diode

=12.0A,

=7.0A,

=6.0A,

120

160

Supply Section

ILK Offset Supply Leakage Current H-VCC=V

=500V 50 μA

CTR

IQHVCC Quiescent HVCC Supply Current (HVCCUV+) - 0.1V 50 120 μA

IQLVCC Quiescent LVCC Supply Current (LVCCUV+) - 0.1V 100 200 μA

f

=100KHz 6 9 mA

IOHVCC

IOLVCC

Operating HV (RMS Value)

Operating LV (RMS Value)

Supply Current

CC

Supply Current

CC

OSC

No Switching 100 200 μA

f

=100KHz 7 11 mA

OSC

No Switching 2 4 mA

UVLO Section

Unit

V

Ω

ns

LVCCUV+ LVCC Supply Under-Voltage Positive Going Threshold (LVCC Start) 11.2 12.5 13.8 V

LVCCUV- LVCC Supply Under-Voltage Negative Going Threshold (LVCC Stop) 8.90 10.0 11.1 V

LVCCUVH LVCC Supply Under-Voltage Hysteresis 2.50 V

HVCCUV+ HVCC Supply Under-Voltage Positive Going Threshold (HVCC Start) 8.2 9.2 10.2 V

HV

HVCCUV-

Supply Under-Voltage Negative Going Threshold (HVCC Stop)

CC

7.8 8.7 9.6 V

HVCCUVH HVCC Supply Under-Voltage Hysteresis 0.5 V

Electrical Characteristics (Continued)

TA=25°C unless otherwise specified.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Symbol Parameter Test Conditions

Specifications Unit

Min Typ Max

Oscillator & Feedback Section

VRT V-I Converter Threshold Voltage

f

Output Oscillation Frequency 94 100 106 KHz

OSC

R

=5.2KΩ

T

1.5 2.0 2.5 V

DC Output Duty Cycle 48 50 52 %

fSS Internal Soft-Start Initial Frequency

f R

SS=fOSC

=5.2KΩ

T

+40kHz,

140 KHz

tSS Internal Soft-Start Time 2 3 4 ms

Protection Section

V

Beginning Voltage to Discharge CSS 0.9 1.0 1.1 V

CssH

V

Beginning Voltage to Charge CSS and Restart 0.16 0.20 0.24 V

CssL

V

LVCC Over-Voltage Protection L-VCC > 21V 21 23 25 V

OVP

V

AOCP Threshold Voltage

AOCP

t

AOCP Blanking Time

BAO

V

OCP Threshold Voltage

OCP

tBO OCP Blanking Time

tDA

Delay Time (Low Side) Detecting from V to Switch Off

(6)

TSD Thermal Shutdown Temperature

ΔV/Δt=-0.1V/µs

< V

V

CS

AOCP

;

ΔV/Δt=-0.1V/µs

V/Δt=-1V/µs

< V

V

CS

OCP

;

ΔV/Δt=-1V/µs

AOCP

ΔV/Δt=-1V/µs

(6)

120 135 150

-1.0 -0.9 -0.8 V

50 ns

-0.64 -0.58 -0.52 V

1.0 1.5 2.0 μs

250 400 ns

Dead-Time Control Section

DT Dead Time

(7)

350 ns

Notes:

6. This parameter, although guaranteed, is not tested in production.

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

°C

Typical Performance Characteristics

V

These characteristic graphs are normalized at TA=25ºC.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

1.1

1.05

C

O

1

Normalized at 25

0.95

0.9

-50 -25 0 25 50 75 100

Temp (OC)

Figure 4. Low-Side MOSFET Duty Cycle

vs. Temperature

1.1

1.05

C

O

1

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 50 75 100

Temp (OC)

Figure 5. Switching Frequency vs. Temperature

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 50 75 100

Figure 6. High-Side VCC (H

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 50 75 100

Figure 8. Low-Side VCC (L

0.95

Normalized at 25

0.9

-50 - 25 0 25 50 75 100

Temp (OC)

) Start vs. Temperature Figure 7. High-Side V

CC

Temp (OC)

) Start vs. Temperature Figure 9. Low-Side VCC(L

CC

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 5 0 75 100

Temp (OC)

(H

CC

Temp (OC)

) Stop vs. Temperature

CC

) Stop vs. Temperature

CC

V

Typical Performance Characteristics (Continued)

These characteristic graphs are normalized at TA=25ºC.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 5 0 75 100

Temp (OC)

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 50 75 100

Figure 10. LVCC OVP Voltage vs. Temperature Figure 11. R

1.10

1.05

at 25Ԩ

1.00

at 25Ԩ

1.10

1.05

1.00

Temp (OC)

oltage vs. Temperature

T

0.95

Normalized

0.90

-50-25 0 255075100

Figure 12.

1.1

1.05

C

O

1

0.95

Normalized at 25

0.9

-50 -25 0 25 50 75 100

Temp( Ԩ )

vs. Temperature Figure 13.

CssL

Temp (OC)

0.95

Normalized

0.90

-50-25 0 255075100

Figure 14. OCP Voltage vs. Temperature

Temp( Ԩ )

vs. Temperature

CssH

Functional Description

f

Ω

1. Basic Operation: FSFR-US series is designed to

drive high-side and low-side MOSFETs complementarily with 50% duty cycle. A fixed dead time of 350ns is introduced between consecutive transitions, as shown in Figure 15.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Figure 15. MOSFETs Gate Drive Signal

2. Internal Oscillator: FSFR-US series employs a

current-controlled oscillator, as shown in Figure 16. Internally, the voltage of R charging / discharging current for the oscillator capacitor,

, is obtained by copying the current flowing out of the

C

T

R

T

pin (I

) using a current mirror. Therefore, the

CTC

switching frequency increases as I

Figure 16. Current Controlled Oscillator

3. Frequency Setting: Figure 17 shows the typical

voltage gain curve of a resonant converter, where the gain is inversely proportional to the switching frequency in the ZVS region. The output voltage can be regulated by modulating the switching frequency. Figure 18 shows the typical circuit configuration for the R opto-coupler transistor is connected to the R modulate the switching frequency.

The minimum switching frequency is determined as:

5.2

k

min

Ω

R

100( )

min

=×

Assuming the saturation voltage of opto-coupler transistor is 0.2V, the maximum switching frequency is determined as:

5.2 4.68

kk

max

fkHz

ΩΩ

( ) 100( )

=+ ×

RR

min max

pin is regulated at 2V and the

T

increases.

CTC

T

kHz

pin, where the

pin to

T

(1)

(2)

To prevent excessive inrush current and overshoot of output voltage during startup, increase the voltage gain of the resonant converter progressively. Since the voltage gain of the resonant converter is inversely proportional to the switching frequency, the soft-start is implemented by sweeping down the switching frequency

from an initial high frequency (f

voltage is established. The soft-start circuit is made by connecting R-C series network on the R in Figure 18. FSFR-US series also has an internal softstart for 3ms to reduce the current overshoot during the initial cycles, which adds 40kHz to the initial frequency of the external soft-start circuit, as shown in Figure 19. The initial frequency of the soft-start is given as:

Figure 17. Resonant Converter Typical Gain Curve

FSFR-US

Figure 18. Frequency Control Circuit

ISS

) until the output

pin, as shown

T

5.2 5.2

ISS

fkHz

kk

()10040()

=+×+

RR

min

Ω

SS

(3)

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

It is typical to set the initial frequency of soft-start two to

three times the resonant frequency (f

) of the resonant

O

network.

The soft-start time is three to four times of the RC time constant. The RC time constant is as follows:

CR •=τ

SSSS

(4)

Figure 19. Frequency Sweeping of Soft-Start

4. Self Auto-Restart: The FSFR-US series can restart

automatically even though any built-in protections are triggered with external supply voltage. As can be seen in Figure 20 and Figure 21, once any protections are triggered, M1 switch turns on and V-I converter is disabled. C

drops to V

C

SS

starts to be discharged until V

SS

. Then, all protections are reset, M1

CssL

across

Css

turns off, and V-I converter resumes at the same time. The FSFR-US starts switching again with soft-start. If the protections occur while V

is under V

Css

level, the switching is terminated immediately, V continues to increase until reaching V

and V

CssL

, then CSS is

CssH

Css

discharged by M1.

For the soft-start time, t

(a) (a)(a)(b) (b)

LV

CC

V

AR

I

Cr

t

stoptS/S

(a)Protections are triggere d, (b) F SFR-US restarts

it can be set as Equation (4).

s/s

(b)

Figure 21. Self Auto-Restart Operation

5. Protection Circuits: The FSFR-US series has several

self-protective functions, such as Over-Current Protection (OCP), Abnormal Over-Current Protection (AOCP), OverVoltage Protection (OVP), and Thermal Shutdown (TSD). These protections are auto-restart mode protections as shown in Figure 22.

Once a fault condition is detected, switching is terminated and the MOSFETs remain off. When LV

falls to the LVCC

CC

stop voltage of 10V or AR signal is HIGH, the protection is reset. The FSFR-US resumes normal operation when

reaches the start voltage of 12.5V.

LV

CC

V

CssH

V

CssL

Figure 22. Protection Blocks

5.1 Over-Current Protection (OCP): When the

sensing pin voltage drops below -0.58V, OCP is triggered and the MOSFETs remain off. This protection has a shutdown time delay of 1.5µs to prevent

Figure 20. Internal Block of AR Pin

After protections trigger, FSFR-US is disabled during the stop-time, t

. The stop-time of FSFR-US can be estimated as:

V

CssL

, where V

stop

(){}

decreases and reaches to

Css

Ω=•= k5||RRCt

MINSSSSSTOP

(5)

premature shutdown during startup.

5.2 Abnormal Over-Current Protection (AOCP): If

the secondary rectifier diodes are shorted, large current with extremely high di/dt can flow through the MOSFET before OCP is triggered. AOCP is triggered without shutdown delay when the sensing pin voltage drops below -0.9V.

5.3 Over-Voltage Protection (OVP): When the LV

CC

reaches 23V, OVP is triggered. This protection is used when auxiliary winding of the transformer to supply V

CC

to FPS is utilized.

5.4 Thermal Shutdown (TSD): The MOSFETs and

the control IC in one package makes it easy for the control IC to detect the abnormal over-temperature of the MOSFETs. If the temperature exceeds approximately 130

°C, the thermal shutdown triggers.

6. Current Sensing Using Resistor: FSFR-US series

senses drain current as a negative voltage, as shown in Figure 23 and Figure 24. Half-wave sensing allows low power dissipation in the sensing resistor, while full-wave sensing has less switching noise in the sensing signal.

Cr

Np

Ns

Control

V

IC

CS

SG PG

R

sense

Ids

I

ds

V

CS

Figure 23. Half-Wave Sensing

I

ds

7. PCB Layout Guidelines: Duty unbalance problems

may occur due to the radiated noise from main transformer, the inequality of the secondary side leakage inductances of main transformer, and so on. Among them, it is one of the dominant reasons that the control components in the vicinity of R primary current flows pattern on PCB layout. The direction of the magnetic field on the components caused by the primary current flow is changed when the high-and low-side MOSFET turn on by turns. The magnetic fields with opposite directions induce a current through, into, or out of the R

pin, which makes the turn-on duration of

T

each MOSFET different. It is strongly recommended to separate the control components in the vicinity of R from the primary current flow pattern on PCB layout. Figure 25 shows an example for the duty-balanced case.

Figure 25. Example for Duty Balancing

pin are enclosed by the

T

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

V

CS

Control

V

IC

CS

SG

Ids

Cr

Np

Ns

PG

R

sense

Ns

Figure 24. Full-Wave Sensing

Physical Dimensions

5.35

5.15

10.70

10.30

26.20

25.80

23.10

22.90

(0.70)

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

3.40

3.00

(1.70)

(R0.50)

14.50

13.50 R0.55

(1.20)

(11 .0 0)

(0.50)

18.50

17.50

8.00

7.00

(R0.50)

MAX 1.30

(5.08)

1.27

15.24

0.70

0.50

MAX 0.80

R0.55

(7.00)

1.30

1.10

0.60

0.40

3.48

2.88

3.40

3.00

NOTES: UNLESS O THERWISE S PECIFIED

A) THIS PACKAGE DOES N OTCOMPLY

TO ANY CURRENT PACKAGIN G STANDARD. B) ALL DIMENSIONS ARE IN MILLIMETERS. C) DIMENSIONS ARE EXCLUSIVE OF BU R RS,

MOLD FLASH,AND TIE BAR EXTRUSIONS.

SIPMODAA09revA

Figure 26. 9-SIP Package

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/

.

Physical Dimensions

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Figure 27. 9-SIP L-Forming Package

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/

.

FSFR-US Series — Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter