FAN7547A LCD Backlight Inverter Drive IC
February 2007
FAN7547A
LCD Backlight Inverter Drive IC
Features
Backlight Lamp Ballast and Soft Dimming
Reduced Number of Components
Wide Range of Operating Voltage (6 to 30V)
Precision Voltage Reference Reduced to 3.4%
Low Standby Current (Typically 50µA)
Soft-Start Function
PWM Control
Analog, Mixed, and PWM Dimming Function
P-Channel MOSFET Drive
Open-Lamp Protections (OLP)
Shutdown Protections (SDP)
14-Pin SOP
Description
The FAN7547A provides all control functions for a
current-fed, push-pull, self-oscillation type converter and
also contains a pulse-width-modulated (PWM) controller
to develop a supply voltage. Typical operating frequency
range is from 30kHz to 100kHz, depending on the cold
cathode fluorescent lamp (CCFL) and the transformer's
characteristics.
14-SOP
Ordering Information
Part Number
FAN7547AM
FAN7547AMX
Package
14-SOP
Pb-Free
Yes
Operating Temperature Range Packing Method
-25°C ~ +85°C
Tube
Tape & Reel
© 2005 Fairchild Semiconductor Corporation
FAN7547A Rev. 1.0.3
www.fairchildsemi.com
FAN7547A LCD Backlight Inverter Drive IC
Internal Block Diagram
OUT
V
Z
SW
V
ref
3V
V
Z
V
CC
Comparator1
UVLO
5V
S/S
1.3V
RCT
Oscillator
120μA
V
b
7V
Comparator4
V
a
Comparator5
V
ref
V
ref
0.1V
Comparator3
40μA
Comparator2
Buffer
Amplifier
V
CC
Internal
Bias
V
CC
1
V
ref
Output
Driver
Q
R
S
2μA
SDP
3.7V
OSC
COMP
FB
OLP
Dimming Control and Mode Selection Block
V
DS
Analog
PWM
Mixed
2V
Comparator6
50kΩ
V
ms
50kΩ
1V
Full Lighting when V
DS
= 3V
FAN7547A Rev. 1.01
GND
Figure 1. Functional Block Diagram of FAN7547A
© 2005 Fairchild Semiconductor Corporation
FAN7547A Rev. 1.0.3
2
www.fairchildsemi.com
FAN7547A LCD Backlight Inverter Drive IC
Pin Configuration
OUT
14
V
CC
1
13
V
CC
12
OSC
11
S/S
10
COMP
9
FB
8
FAN7545A
1
GND
2
V
DS
3
V
ref
4
V
ms
5
RCT
6
OLP
7
SDP
FAN7547A Rev. 1.00
Figure 2. Pin Configuration (Top View)
Pin Definitions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Name
GND
V
DS
V
ref
V
ms
RCT
OLP
SDP
FB
COMP
S/S
OSC
V
CC
V
CC
1
OUT
I/O
Ground
I
O
I
I
I
I
Dimming Voltage Input
Reference Voltage
Dimming Mode Selection
Description
Burst Dimming Frequency Set
Open-Lamp Protection
Shutdown Protection
Feedback Input
Error Amplifier Output
Soft-Start
I
I
I
O
Main Ct
Supply Voltage
Output Drive Source Voltage
Output Drive
© 2005 Fairchild Semiconductor Corporation
FAN7547A Rev. 1.0.3
3
www.fairchildsemi.com
FAN7547A 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. -25°C
≤
T
A
≤
85°C and V
CC
=10V unless otherwise specified.
Symbol
V
CC
T
J
T
A
T
STG
P
D
Supply Voltage
Parameter
Operating Junction Temperature
Operating Temperature Range
Storage Temperature Range
Power Dissipation
Value
6 to 30
150
-25 to 85
-65 to 150
0.5
Unit
V
°C
°C
°C
W
© 2005 Fairchild Semiconductor Corporation
FAN7547A Rev. 1.0.3
4
www.fairchildsemi.com
FAN7547A LCD Backlight Inverter Drive IC
Electrical Characteristics
Unless otherwise noted, these specifications apply to the operating ambient temperatures for the FAN7547A with
-25°C
≤
T
A
≤
85°C and V
CC
= 10V.
Symbol
UVLO SECTION
V
ST
I
ST
I
CC
V
ref
I
SS
I
pwm
f
pwm
V
pwmh
V
pwmI
V
a
V
b
V
a
V
b
V
a
V
b
V
sa
V
sp
V
sc
V
open
I
sd
V
sd
V
OH
V
OL
t
r
t
f
V
UV
Parameter
Start Voltage
Start Current
Operating Current
Reference Voltage
Soft -Start Charge Current
PWM Discharge Current
Operating Frequency
Osc High Voltage
Osc Low Voltage
V
CC
= 4.5V
Conditions
Min. Typ. Max. Unit
4.9
5.4
50
5.5
2.95
33
48
170
3.05
40
70
200
1.3
0.1
0
3
2.1
0
1.2
0
1.5
0.7
1.2
2.0
1.0
1.5
3.0
2
3.0
9
120
60
2
2.5
2.9
2.5
3.0
3
2.5
1.3
1.8
3.5
3
3.5
10
1
200
120
4
3
5.9
200
8.0
3.15
47
85
230
V
μA
mA
V
μA
μA
Hz
V
V
V
V
V
V
V
V
V
V
V
V
μA
V
V
V
ns
ns
V
7V < V
CC
< 30V
T
J
= 25°C, I
ref
= 0mA, 7V < V
CC
< 30V
C
SS
= 4V
C
SS
= 4V
7V < V
CC
< 30V
REFERENCE SECTION
SOFT-START SECTION
OSCILLATOR SECTION
DIMMING SECTION
Analog Dimming Range
PWM Dimming Range
Mixed Dimming Range
V
ms
> 2V
V
ms
< 1V
V
ms
=1.5V or open
MODE SELECTION
Analog Dimming Select Voltage
PWM Dimming Select Voltage
Mixed Dimming Select Voltage
Open-Lamp Detect Voltage
Shutdown Current
Shutdown Voltage
Output High Voltage
Output Low Voltage
Rising Time
Falling Time
Output Voltage with UVLO
Activated
V
CC
= 10V
V
CC
= 10V
V
CC
= 10V
V
CC
= 10V
V
CC
= 4V
7V < V
CC
< 30V
7V < V
CC
< 30V
OPEN-LAMP PROTECTION
2.5
1
2.5
8
SHUTDOWN PROTECTION
OUTPUT SECTION
© 2005 Fairchild Semiconductor Corporation
FAN7547A Rev. 1.0.3
5
www.fairchildsemi.com
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