FAN7318B — LCD Backlight Inverter Drive IC
August 2009
FAN7318B
LCD Backlight Inverter Drive IC
Features
High-Efficiency Single-Stage Power Conversion
Wide Input Voltage Range: 6V to 30V
Backlight Lamp Ballast and Soft Dimming
Minimal External Components Required
Precision Voltage Reference Trimmed to 2%
Half-Bridge Topology
Soft-Start
PWM Control at Fixed Frequency
Analog Dimming Function
Burst Dimming Function
Programmable Striking Frequency
Open-Lamp Protection
Open-Lamp Regulation
Over-Voltage Protection
Short-Lamp Protection
CMP-High Protection
Thermal Shutdown
20-Pin SOIC
Description
The FAN7318B is a LCD backlight inverter drive IC that
controls P-N half-bridge topology.
The FAN7318B provides a low-cost solution and reduces
external components by integrating proprietary wave
rectifiers for open-lamp protection and regulation. The
operating voltage range of the FAN7318B is wide, so an
external regulator isn’t necessary to supply the voltage to
the IC.
The FAN7318B provides various protections, such as
open-lamp regulation, over-voltage protection, open-
lamp protection, short-Lamp protection, CMP-high
protection, to increase the system reliability. The
FAN7318B provides burst dimming and analog dimming.
The FAN7318B is available in a 20-SOIC package.
Applications
LCD TV
LCD Monitor
Ordering Information
Part
Number
FAN7318BM
FAN7318BMX
Operating
Temperature
-25 to +85°C
Package
20-Lead, Small Outline Integrated Circuit (SOIC)
Eco
Status
RoHS
Packing
Method
Rail
Tape & Reel
For Fairchild’s definition of Eco Status, please visit:
http://www.fairchildsemi.com/company/green/rohs_green.html.
Protected under U.S. patent no. 5,652,479.
© 2009 Fairchild Semiconductor Corporation
FAN7318B • 1.0.0
www.fairchildsemi.com
FAN7318B — LCD Backlight Inverter Drive IC
Pin Definitions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Name
TIMER
CMP
ADIM
CT
REF
BCT
BDIM
ENA
GND
OUTB
OUTA
VIN
OLR4
OLP4
OLR3
OLP3
OLR2
OLP2
Description
This pin is for protection delay time setting.
Error amplifier output. Typically, a compensation capacitor is connected to this pin from the
ground.
This pin is the input for negative analog dimming.
This pin is for programming the switching frequency. Typically, a capacitor is connected to
this pin from ground and a resistor is connected to this pin from the REF pin.
This pin is 5V reference output. Typically, resistors are connected to this pin from the CT pin
and the BCT pin.
This pin is for programming the frequency of the burst dimming. Typically, a capacitor is
connected to this pin from ground and a resistor is connected to this pin from the REF pin.
This pin is the input for negative burst dimming. The voltage range of 0.5 to 2V at this pin
controls the burst-mode duty cycle from 0% to 100%.
This pin turns the IC on / off.
This pin is the ground.
This pin is NMOS gate-drive output.
This pin is PMOS gate-drive output.
This pin is the supply voltage of the IC.
This pin is for open-lamp regulation. Its functions are the same as the OLR1 pin.
This pin is for open-lamp protection and feedback control of lamp currents. Its functions are
the same as the OLP1 pin.
This pin is for open-lamp regulation. Its functions are the same as the OLR1 pin.
This pin is for open-lamp protection and feedback control of lamp currents. Its functions are
the same as the OLP1 pin.
This pin is for open-lamp regulation. Its functions are the same as the OLR1 pin.
This pin is for open-lamp protection and feedback control of lamp currents. Its functions are
the same as the OLP1 pin.
This pin is for open-lamp regulation and short-lamp protection. It has the same functions as
other OLR pins and is connected to the full-wave rectifier internally. When the maximum of
rectified OLR inputs is between 1.34V and 2V, the error amplifier output current is limited to
3.0µA. When the maximum of rectified OLR inputs reaches 2V, the error amplifier output
current is 0A and its output voltage maintains constant. The maximum of rectified OLR
inputs is inputted to the negative of another error amplifier for feedback control of lamp
voltage. When the maximum of rectified OLR inputs is more than 2.2V, another error
amplifier for OLR is operating and lamp voltage is regulated. In normal mode, if the
maximum of rectified OLR inputs is higher than 1.34V or if the minimum of rectified OLR
inputs is lower than 0.3V for a predetermined time by the TIMER pin capacitor and an
internal current source 50µA; the IC shuts down to protect the system in over-voltage
condition or short-lamp condition, respectively.
This pin is for open-lamp protection and feedback control of lamp currents. It has the same
functions as other OLP pins and is connected to the half-wave rectifier and the full-wave
rectifier internally. In striking mode, if the minimum of rectified OLP inputs is less than 0.7V
for a time predetermined by the TIMER pin capacitor and an internal current source or; in
normal mode, if the minimum of rectified OLP inputs is less than 0.5V for another
predetermined time by the TIMER pin capacitor and another internal current source; the IC
shuts down to protect the system in open-lamp condition. The maximum of rectified OLP
inputs is inputted to the negative of the error amplifier for feedback control of lamp current.
19
OLR1
20
OLP1
© 2009 Fairchild Semiconductor Corporation
FAN7318B • 1.0.0
www.fairchildsemi.com
4
FAN7318B — LCD Backlight Inverter Drive IC
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.
Symbol
V
IN
T
A
T
J
T
STG
θ
JA
P
D
IC Supply Voltage
Parameter
Operating Temperature Range
Operating Junction Temperature
Storage Temperature Range
Thermal Resistance Junction-Air
Power Dissipation
(1,2)
Min.
6
-25
-65
Max.
30
+85
+150
+150
90
1.4
Unit
V
°C
°C
°C
°C/W
W
Notes:
1. Thermal resistance test board; size: 76.2mm x 114.3mm x 1.6mm (1S0P); JEDEC standard: JESD51-2, JESD51-3.
2. Assume no ambient airflow.
Pin Breakdown Voltage
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Name
TIMER
CMP
ADIM
CT
REF
BCT
BDIM
ENA
GND
OUTB
OUTA
VIN
OLR4
OLP4
OLR3
OLP3
OLR2
OLP2
OLR1
OLP1
Value
7
7
7
7
7
7
7
7
30
30
30
±7
±7
±7
±7
±7
±7
±7
±7
Unit
V
© 2009 Fairchild Semiconductor Corporation
FAN7318B • 1.0.0
www.fairchildsemi.com
5
ST - Low Power RF
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