FLS-XS Series — Half-Bridge LLC Resonant
Control IC for Lighting
Features
Description
Variable Frequency Control with 50% Duty Cycle
The FLS-XS series of general lighting power controllers
includes highly integrated power switches for medium- to
high-power lumens applications. Offering everything
necessary to build a reliable and robust half-bridge
resonant converter, the FLS-XS series simplifies designs
and improves productivity, while improving performance.
The FLS-XS series combines power MOSFETs with fastrecovery 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 common-mode noise
cancellation capability, which guarantees stable
operation with excellent noise immunity. The fastrecovery body diode of the MOSFETs improves reliability
against abnormal operation conditions, while minimizing
the effect of reverse recovery. Using zero voltage
switching (ZVS) dramatically reduces the switching
losses and significantly improves efficiency. ZVS also
reduces switching noise noticeably, which allows a smallsized Electromagnetic Interference (EMI) filter.
for Half-Bridge Resonant Converter Topology
High Efficiency through Zero Voltage Switching (ZVS)
Internal UniFET™ with Fast-Recovery Body Diode
Fixed Dead Time (350ns) Optimized for MOSFETs
Up to 300kHz Operating Frequency
Auto-Restart Operation for All Protections with
External LVCC
Protection Functions: Over-Voltage Protection (OVP),
Over-Current Protection (OCP), Abnormal OverCurrent Protection (AOCP), Internal Thermal
Shutdown (TSD)
Applications
General LED Lighting Power
Industrial, Commercial, and Residential LED
Lighting Fixtures
Outdoor
Lighting: Street, Roadway, Parking,
Construction and Ornamental LED Lighting Fixtures
The FLS-XS series can be applied to resonant converter
topologies such as series resonant, parallel resonant,
and LLC resonant converters.
Ordering Information
Part Number
Package
Operating
Junction
Temperature
FLS2100XS
FLS1800XS
FLS1700XS
9-SIP
FLS1600XS
-40 to +130°C
RDS(ON_MAX)
Maximum Output Power
without Heatsink
(1,2)
(VIN=350~400V)
Maximum Output
Power with Heatsink
(1,2)
(VIN=350~400V)
0.51Ω
180W
400W
0.95Ω
120W
260W
1.25Ω
100W
200W
1.55Ω
80W
160W
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.
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
www.fairchildsemi.com
FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
December 2010
FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
FLS-XS
Series
Application Circuit Diagram
Figure 1. Typical Application Circuit for LLC Resonant Half-Bridge Converter
Block Diagram
Figure 2. Internal Block Diagram
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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2
Figure 3. Package Diagram
Pin Definitions
Pin #
Name
1
VDL
This is the drain of the high-side MOSFET, typically connected to the input DC link voltage.
Description
2
AR
This pin is for discharging the external soft-start capacitor when any protections are
triggered. When the voltage of this pin drops to 0.2V, all protections are reset and the
controller starts to operate again.
3
RT
This pin programs the switching frequency. Typically, an opto-coupler is connected to control
the switching frequency for the output voltage regulation.
4
CS
This pin senses the current flowing through the low-side MOSFET. Typically, negative
voltage is applied on this pin.
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
9
HVCC
No connection
This is the supply voltage of the high-side gate-drive circuit IC.
10
VCTR
This is the drain of the low-side MOSFET. Typically, a transformer is connected to this pin.
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Pin Configuration
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. TA=25°C unless otherwise specified.
Symbol
VDS
LVCC
Parameter
Min.
Maximum Drain-to-Source Voltage (VDL-VCTR and VCTR-PG)
Low-Side Supply Voltage
Max.
Unit
500
V
-0.3
25.0
V
-0.3
25.0
V
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
RT Pin Input Voltage
-0.3
5.0
V
50
V/ns
HVCC to VCTR High-Side VCC Pin to Low-Side Drain Voltage
HVCC
dVCTR/dt
PD
TJ
TSTG
Allowable Low-Side MOSFET Drain Voltage Slew Rate
Total Power Dissipation
(3)
Maximum Junction Temperature
FLS2100XS
12.0
FLS1800XS
11.7
FLS1700XS
11.6
FLS1600XS
11.5
(4)
W
+150
(4)
°C
Recommended Operating Junction Temperature
-40
+130
Storage Temperature Range
-55
+150
°C
±30
V
MOSFET Section
VDGR
Drain Gate Voltage (RGS=1MΩ)
VGS
Gate Source (GND) Voltage
IDM
Drain Current Pulsed
(5)
500
FLS2100XS
32
FLS1800XS
23
FLS 1700XS
20
FLS 1600XS
18
FLS2100XS
FLS1800XS
ID
V
Continuous Drain Current
FLS 1700XS
FLS 1600XS
TC=25°C
10.5
TC=100°C
6.5
TC=25°C
7.0
TC=100°C
4.5
TC=25°C
6.0
TC=100°C
3.9
TC=25°C
4.5
TC=100°C
2.7
A
A
Package Section
Torque
Recommended Screw Torque
5~7
kgf·cm
Notes:
3. Per MOSFET when both MOSFETs are conducting.
4. The maximum value of the recommended operating junction temperature is limited by thermal shutdown.
5. Pulse width is limited by maximum junction temperature.
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Absolute Maximum Ratings
TA=25°C unless otherwise specified.
Symbol
θJC
Parameter
Value
Junction-to-Case Center Thermal Impedance
(Both MOSFETs Conducting)
FLS2100XS
10.44
FLS1800XS
10.68
FLS 1700XS
10.79
FLS 1600XS
10.89
Unit
ºC/W
Electrical Characteristics
TA=25°C unless otherwise specified.
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
MOSFET Section
BVDSS
RDS(ON)
trr
Drain-to-Source Breakdown Voltage
On-State Resistance
Body Diode Reverse
(6)
Recovery Time
ID=200μA, TA=25°C
500
V
ID=200μA, TA=125°C
540
FLS2100XS
VGS=10V, ID=6.0A
0.41
0.51
FLS1800XS
VGS=10V, ID=3.0A
0.77
0.95
FLS 1700XS
VGS=10V, ID=2.0A
1.00
1.25
FLS 1600XS
VGS=10V, ID=2.25A
1.25
1.55
FLS2100XS
VGS=0V, IDiode=10.5A,
dIDiode/dt=100A/μs
120
FLS1800XS
VGS=0V, IDiode=7.0A,
dIDiode/dt=100A/μs
160
FLS 1700XS
VGS=0V, IDiode=6.0A,
dIDiode/dt=100A/μs
160
FLS 1600XS
VGS=0V, IDiode=5.0A,
dIDiode/dt=100A/μs
65
Ω
ns
Supply Section
ILK
Offset Supply Leakage Current
HVCC=VCTR=500V
50
μA
IQHVCC
Quiescent HVCC Supply Current
(HVCCUV+) - 0.1V
50
120
μA
IQLVCC
Quiescent LVCC Supply Current
(LVCCUV+) - 0.1V
100
200
μA
IOHVCC
Operating HVCC Supply Current
(RMS Value)
fOSC=100KHz
6
9
mA
No Switching
100
200
μA
IOLVCC
Operating LVCC Supply Current
(RMS Value)
fOSC=100KHz
7
11
mA
No Switching
2
4
mA
Continued on the following page…
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Thermal Impedance
TA=25°C unless otherwise specified.
UVLO Section
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)
8.9
10.0
11.1
V
LVCCUVH
LVCC Supply Under-Voltage Hysteresis
HVCCUV+
HVCC Supply Under-Voltage Positive-Going Threshold (HVCC Start)
8.2
9.2
10.2
V
HVCCUV-
HVCC Supply Under-Voltage Negative-Going Threshold (HVCC Stop)
7.8
8.7
9.6
V
HVCCUVH
HVCC Supply Under-Voltage Hysteresis
2.50
V
0.5
V
Oscillator & Feedback Section
VRT
V-I Converter Threshold Voltage
fOSC
Output Oscillation Frequency
DC
Output Duty Cycle
fSS
Internal Soft-Start Initial Frequency
tSS
Internal Soft-Start Time
RT=5.2KΩ
1.5
2.0
2.5
V
94
100
106
KHz
48
50
52
%
140
fSS=fOSC+40kHz, RT=5.2KΩ
KHz
2
3
4
ms
Protection Section
VCssH
Beginning Voltage to Discharge CSS
0.9
1.0
1.1
V
VCssL
Beginning Voltage to Charge CSS and
Restart
0.16
0.20
0.24
V
VOVP
LVCC Over-Voltage Protection
21
23
25
V
VAOCP
AOCP Threshold Voltage
-1.0
-0.9
-0.8
V
LVCC > 21V
(6)
tBAO
AOCP Blanking Time
VOCP
OCP Threshold Voltage
VCS < VAOCP
(6)
tBO
OCP Blanking Time
VCS < VOCP
tDA
Delay Time (Low Side) Detecting from
(6)
VAOCP to Switch Off
TSD
Thermal Shutdown Temperature
(6)
50
ns
-0.64
-0.58
-0.52
V
1.0
1.5
2.0
μs
250
400
ns
+135
+150
°C
+120
Dead-Time Control Section
DT
(7)
Dead Time
350
ns
Notes:
6. This parameter, although guaranteed by design, is not tested in production.
7. These parameters, although guaranteed, are tested only in EDS (wafer test) process.
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
www.fairchildsemi.com
6
FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Electrical Characteristics
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
These characteristic graphs are normalized at TA=25ºC.
1
0.95
1
0.95
0.9
0.9
-50
-25
0
25
50
75
-50
100
-25
0
Temp (OC)
50
75
100
Figure 5. Switching Frequency vs. Temperature
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
Figure 4. Low-Side MOSFET Duty Cycle
vs. Temperature
1
0.95
0.9
1
0.95
0.9
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temp (OC)
Temp (OC)
Figure 6. High-Side VCC (HVCC) Start vs. Temperature
Figure 7. High-Side VCC (HVCC) Stop vs. Temperature
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
25
Temp (OC)
1
0.95
1
0.95
0.9
0.9
-50
-25
0
25
50
75
-50
100
Figure 8. Low-Side VCC (LVCC) Start vs. Temperature
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
-25
0
25
50
75
100
Temp (OC)
Temp (OC)
Figure 9. Low-Side VCC (LVCC) Stop vs. Temperature
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Typical Performance Characteristics
1.1
1.1
1.05
1.05
Normalized at 25OC
Normalized at 25OC
These characteristic graphs are normalized at TA=25ºC.
1
0.95
0.9
1
0.95
0.9
-50
-25
0
25
50
75
100
-50
-25
0
Temp (OC)
Figure 10. LVCC OVP Voltage vs. Temperature
50
75
100
Figure 11. RT Voltage vs. Temperature
1.1
1.1
1.05
1.05
Normalized at 25℃
Normalized at 25℃
25
Temp (OC)
1
0.95
0.9
1
0.95
0.9
-50
-25
0
25
50
75
100
-50
Temp(℃)
-25
0
25
50
75
100
Temp(℃)
Figure 12. VCssL vs. Temperature
Figure 13. VCssH vs. Temperature
1.1
Normalized at 25OC
1.05
1
0.95
0.9
-50
-25
0
25
50
75
100
Temp (OC)
Figure 14. OCP Voltage vs. Temperature
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Typical Performance Characteristics (Continued)
1. Basic Operation. FLS-XS 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.
Figure 15. MOSFETs Gate Drive Signal
2. Internal Oscillator: FLS-XS series employs a currentcontrolled oscillator, as shown in Figure 16. Internally,
the voltage of the RT pin is regulated at 2V and the
charging / discharging current for the oscillator capacitor,
CT, is obtained by copying the current flowing out of the
RT pin (ICTC) using a current mirror. Therefore, the
switching frequency increases as ICTC increases.
Figure 17. Resonant Converter Typical Gain Curve
Figure 16. Current-Controlled Oscillator
Figure 18. Frequency Control Circuit
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 RT pin, where the
opto-coupler transistor is connected to the RT pin to
modulate the switching frequency.
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
ISS
from an initial high frequency (f ) until the output
voltage is established. The soft-start circuit is made by
connecting R-C series network on the RT pin, as shown
in Figure 18. FLS-XS series also has a 3ms internal softstart 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:
The minimum switching frequency is determined as:
f min =
5.2kΩ
× 100(kHz )
Rmin
(1)
Assuming the saturation voltage of opto-coupler
transistor is 0.2V, the maximum switching frequency is
determined as:
f
max
5.2 k Ω 4.68k Ω
=(
+
) × 100(kHz )
Rmin
Rmax
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
f ISS = (
(2)
5.2k Ω 5.2k Ω
+
) × 100 + 40 (kHz )
Rmin
RSS
(3)
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Functional Description
τ = RSS • CSS
(a)
(b)
(a)
(b) (a)
(b)
LVcc
VAR
VCssH
VCssL
(4)
ICr
tstop
tS/S
(a) Protections are triggered, (b) FLS-XS restarts
Figure 21. Self Auto-Restart Operation
5. Protection Circuits: The FLS-XS 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.
Figure 19. Frequency Sweeping of Soft-Start
4. Self Auto-Restart: The FLS-XS series can restart
automatically even when any built-in protections are
triggered with external supply voltage. As can be seen in
Figure 20 and Figure 21, once a protection is triggered,
the M1 switch turns on and the V-I converter is disabled.
CSS starts to discharge until VCss across CSS drops to
VCssL. Then, all protections are reset, M1 turns off, and
the V-I converter resumes. The FLS-XS starts switching
again with soft-start. If the protections occur while VCss is
under VCssL and VCssH level, the switching is terminated
immediately, VCss continues to increase until reaching
VCssH, then CSS is discharged by M1.
Once a fault condition is detected, switching is terminated
and the MOSFETs remain off. When LVCC falls to the LVCC
stop voltage of 10V or AR signal is HIGH, the protection is
reset. The FLS-XS resumes normal operation when LVCC
reaches the start voltage of 12.5V.
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
premature shutdown during startup.
Figure 20. Internal Block of AR Pin
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 if the sensing pin voltage
drops below -0.9V.
After protections trigger, FLS-XS is disabled during the
stop-time, tstop, where VCss decreases and reaches to
VCssL. The stop-time of FLS-XS can be estimated as:
t STOP = CSS • {(RSS + RMIN ) || 5kΩ}
(5)
The soft-start time ts/s can be set from Equation (4).
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
It is typical to set the initial frequency of soft-start two to
three times the resonant frequency (fO) of the resonant
network. The soft-start time is three to four times the RC
time constant. The RC time constant is:
5.4 Thermal Shutdown (TSD): Having the MOSFETs
and the control IC in one package makes it easier for
the control IC to detect the abnormal over-temperature
of the MOSFETs. If the temperature exceeds
approximately 130°C, thermal shutdown triggers.
6. Current Sensing Using a Resistor: FLS-XS 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
Ns
Control
IC
VCS
Ids
CS
SG
PG
Rsense
VCS
Ids
Figure 25. Example for Duty Balancing
Figure 23. Half-Wave Sensing
Ids
VCS
Cr
Control
IC
VCS
Np
CS
PG
SG
Rsense
Ns
Ns
Ids
Figure 24. Full-Wave Sensing
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
7. PCB Layout Guidelines: Duty imbalance problems
may occur due to the radiated noise from the main
transformer, the inequality of the secondary side-leakage
inductances of main transformer, and so on. This is one
of the reasons that the control components in the vicinity
of RT pin are enclosed by the primary current flow 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 RT pin, which
changes the turn-on duration of each MOSFET. It is
strongly recommended to separate the control
components in the vicinity of RT pin from the primary
current flow pattern on PCB layout. Figure 25 shows an
example for the duty-balanced case.
5.3 Over-Voltage Protection (OVP): When the LVCC
reaches 23V, OVP is triggered. This protection is used
when auxiliary winding of the transformer to supply VCC
to the FPS™ is utilized.
FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
Physical Dimensions
Figure 26. 9-Lead Single Inline Package (SIP)
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/.
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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FLS-XS Series — Half-Bridge LLC Resonant Control IC for Lighting
© 2010 Fairchild Semiconductor Corporation
FLS-XS Series • Rev.1.0.0
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