FAN7318 — LCD Backlight Inverter Drive IC
June 2011
FAN7318
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
Short-Lamp Protection
CMP-High Protection
FB-High Protection
Thermal Shutdown
20-Pin SOIC
Description
The FAN7318 is a LCD backlight inverter drive IC that
controls P-N half-bridge topology.
The FAN7318 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 FAN7318 is wide, so an
external regulator isn’t necessary to supply the voltage to
the IC.
The FAN7318 provides various protections, such as
open-lamp regulation, open-lamp protection, short-Lamp
protection, CMP-high protection, and FB-high protection,
to increase the system reliability. The FAN7318 provides
burst dimming and analog dimming.
The FAN7318 is available in a 20-SOIC package.
Applications
LCD TV
LCD Monitor
Ordering Information
Part Number
FAN7318M
FAN7318MX
Operating
Temperature
-25 to +85°C
Package
20-Lead, Small Outline Integrated Circuit (SOIC)
Packing Method
Rail
Tape & Reel
© 2009 Fairchild Semiconductor Corporation
FAN7318 • 1.0.2
www.fairchildsemi.com
FAN7318 — 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 burst mode duty cycle from 0% to 100%.
This pin is for turning on/off the IC.
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
3.2 A; and 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 1.35V or if the minimum of rectified OLR
inputs is lower than 0.3V for a predetermined time by the TIMER pin capacitor and a internal
current source 50 A, the IC shuts down to protect the system in over-voltage condition,
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 predetermined time 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
FAN7318 • 1.0.2
www.fairchildsemi.com
4
FAN7318 — 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
Max.
30
+85
+150
Unit
V
°C
°C
°C
°C/W
W
-65
+150
90
1.4
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
10
30
30
±7
±7
±7
±7
±7
±7
±7
±7
Unit
V
© 2009 Fairchild Semiconductor Corporation
FAN7318 • 1.0.2
www.fairchildsemi.com
5
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