2004 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.0.1
Features
Wide Dimming Range
Analog dimming ( 2.5 : 1 )
Burst dimming ( >100 : 1 )
High Efficiency Single Stage Power Conversion
Wide Input Voltage Range 7.4V to 20V
Back Light Lamp Ballast and Soft Dimming
Few External Components
Precision Voltage Reference Trimmed to 2%
ZVS full-bridge topology
Soft Start
PWM Control at fixed frequency
Analog, Burst Dimming Function
Open Lamp Protection
Open Lamp Regulation
Short Lamp Protection
Thermal Protection
20 Pin SSOP
Description
The FAN7315 provides all the control functions for a
series parallel resonant converter and also contains a pulse
width modulation (PWM) controller to develop a supply
voltage. Typical operating frequency range is between
30kHz and 250kHz depending on the CCFL and the
transformer's characteristics.
20-SSOP
FAN7315
LCD Back Light Inverter Drive IC
FAN7315
4
Absolute Maximum Ratings
Vcc=12V, for typical values Ta=25
C, for min/max values Ta is the operating ambient temperature range with
-40
C
Ta
85
C and 7.4V
Vcc
20V, unless otherwise specified.
Note:
1. Thermal resistance test board
Size: 76.2mm * 114.3mm * 1.6mm(1S0P)
JEDEC standard: JESD51-3, JESD51-7
2. Assume no ambient airflow
Characteristics
Symbol
Value
Unit
Supply Voltage
V
CC
7.4 ~ 20
V
Operating Temperature Range
Topr
-40 ~ 85
C
Storage Temperature Range
Tstg
-65 ~ 150
C
Thermal Resistance Junction-Air (Note1,2)
R
JA
112
C/W
Power Dissipation
Pd
1.1
W
FAN7315
5
Electrical Characteristics
Vcc=12V, for typical values Ta=25
C, for min/max values Ta is the operating ambient temperature range with
-40
C
Ta
85
C and 7.4V
Vcc
20V, unless otherwise specified.
Characteristics
Symbol
Test Condition
Min.
Typ.
Max.
Unit
REFERENCE SECTION
Load Regulation
V25load
0
I25
3mA
-
2
25
mV
Line Regulation
V25line 7.4V
V
CC
20V
-
2
25
mV
2.5V Regulation Voltage
V25
-
2.44
2.49
2.54
V
OSCILLATOR SECTION(MAIN)
Oscillation Frequency
fosc
Ta=25
C, Ct = 330pF,
Rt = 45k
93
100
107
kHz
Ct = 330pF, Rt = 45k
89
100
111
kHz
CT High Voltage
Vcth
-
-
1.95
-
V
CT Low Voltage
Vbctl
-
-
0.5
-
V
OSCILLATOR SECTION(BURST)
Oscillation Frequency
foscb
Ctb = 6.8nF, Rt=45k
150
191
232
Hz
BCT High Voltage
Vbcth
-
-
2
-
V
BCT Low Voltage
Vbctl
-
-
0.5
-
V
ERROR AMP SECTION
Error Amp Transconductance(Note1)
Gm
Va = 1~2.5V
100
360
600
umho
Output Sink Current
lsin
EA_OUT = 1V
44
73
100
uA
Output Source Current
lsur
EA_OUT = 1V
33
50
67
uA
Open Lamp Regulation Current
Iolr
OLR=2.5V
160
240
320
uA
EA_OUT High Volgate
Vea_outh
2.2
2.5
2.8
V
SOFT START SECTION
Soft Start Current
I
ss
S_S=0V
3.5
5.2
6.9
uA
Soft Start Clamping Voltage
Vssh
-
2.2
2.55
2.9
V
PROTECTION SECTION
Open Lamp Protection Voltage
Volp
-
245
300
425
mV
Open Lamp Regulation Voltage
Volr
-
1.8
2
2.2
V
Short Circuit Protection Voltage
Vscp
-
1.75
2
2.25
V
Thermal Shutdown On Temp.(Note1)
TSDon
-
130
150
170
C
TSD Hysterisis(Note1)
TSDhy
-
-
30
-
C
UNDER VOLTAGE LOCK OUT SECTION
Start Threshold Voltage On
Vthon
-
5.2
6.3
7.4
V
UVLO Hysteresis
Vhys
-
100
300
500
mV
Start Up Current
Ist
V
CC
= Vth-0.2V
48
85
122
uA
Operating Supply Current
Iop
V
CC
= 12V
-
-
2
mA
Stand-by Current
Isb
V
CC
= 12V, ENA=0V
55
80
105
uA
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