www.fairchildsemi.com
FAN7315
LCD Back Light Inverter Drive IC
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
Rev. 1.0.1
©2004 Fairchild Semiconductor Corporation
FAN7315
Internal Block Diagram
RT
OSCILLATOR
Output
Driver
OUTB
CT
5.2uA
S_S
-
+
+
Output
Control
Logic
Output
Driver
OUTD
PGND
OUTC
OUTA
EA_OUT
Thermal
protection
+
-
Error Amp.
Q
SET
ADIM
EA_IN
R
UVLO
-
+
+
-
2V
300mV
OLP
S
olr
240uA
S
burst
240uA
Q
CLR
S
SCP
OLR
2V
BCT
BDIM
AGND
2
-
-
+
+
S
olr
Voltage
Reference
&
Internal
Bias
S
burst
UVLO
2.5VREF
REF
+
-
ENA
1.4V
VIN
VIN
+
-
UVLO 7.4V
FAN7315
Pin Assignments
SCP
OUTB
OUTA
VIN
PGND
OUTC OUTD
CT
RT
BCT
20
19
18
17
16
15
14
13
12
11
FAN7315
1
OLP
2
OLR
3
ENA
4
S_S
5
AGND
6
REF
7
ADIM
8
BDIM
9
EA_IN
10
EA_OUT
Pin Definitions
No
1
2
3
4
5
6
7
8
9
10
Name
OLP
OLR
ENA
S/S
AGND
V25
ADIM
BDIM
EA_IN
EA_OUT
Function Description
Open Lamp Protection
Open Lamp Regulation
Enable Input
Soft Start
Analog Ground
2.5V Reference Voltage
Analog Dimming Input
Burst Dimming Input
Error Amplifier Input
Error Amplifier Output
No
11
12
13
14
15
16
17
18
19
20
Name
BCT
RT
CT
OUTD
OUTC
PGND
VIN
OUTA
OUTB
SCP
Function Description
Burst Dimming Timing Capacitor
Timing Resistor
Timing Capacitor
NMOSFET Drive Output D
PMOSFET Drive Output C
Power Ground
Supply Voltage
PMOSFET Drive Output A
NMOSFET Drive Output B
Short Circuit Protection
3
FAN7315
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.
Characteristics
Supply Voltage
Operating Temperature Range
Storage Temperature Range
Thermal Resistance Junction-Air (Note1,2)
Power Dissipation
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
Symbol
V
CC
Topr
Tstg
R
θJA
Pd
Value
7.4 ~ 20
-40 ~ 85
-65 ~ 150
112
1.1
Unit
V
°C
°C
°C/W
W
4
FAN7315
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
REFERENCE SECTION
Load Regulation
Line Regulation
2.5V Regulation Voltage
OSCILLATOR SECTION(MAIN)
Oscillation Frequency
fosc
Ta=25°C, Ct = 330pF,
Rt = 45k
Ct = 330pF, Rt = 45k
CT High Voltage
CT Low Voltage
OSCILLATOR SECTION(BURST)
Oscillation Frequency
BCT High Voltage
BCT Low Voltage
ERROR AMP SECTION
Error Amp Transconductance(Note1)
Output Sink Current
Output Source Current
Open Lamp Regulation Current
EA_OUT High Volgate
SOFT START SECTION
Soft Start Current
Soft Start Clamping Voltage
PROTECTION SECTION
Open Lamp Protection Voltage
Open Lamp Regulation Voltage
Short Circuit Protection Voltage
Thermal Shutdown On Temp.(Note1)
TSD Hysterisis(Note1)
UNDER VOLTAGE LOCK OUT SECTION
Start Threshold Voltage On
UVLO Hysteresis
Start Up Current
Operating Supply Current
Stand-by Current
Vthon
Vhys
Ist
Iop
Isb
-
-
V
CC
= Vth-0.2V
V
CC
= 12V
V
CC
= 12V, ENA=0V
5.2
100
48
-
55
6.3
300
85
-
80
7.4
500
122
2
105
V
mV
uA
mA
uA
Volp
Volr
Vscp
TSDon
TSDhy
-
-
-
-
-
245
1.8
1.75
130
-
300
2
2
150
30
425
2.2
2.25
170
-
mV
V
V
°C
°C
I
ss
Vssh
S_S=0V
-
3.5
2.2
5.2
2.55
6.9
2.9
uA
V
Gm
lsin
lsur
Iolr
Vea_outh
Va = 1~2.5V
EA_OUT = 1V
EA_OUT = 1V
OLR=2.5V
100
44
33
160
2.2
360
73
50
240
2.5
600
100
67
320
2.8
umho
uA
uA
uA
V
foscb
Vbcth
Vbctl
Ctb = 6.8nF, Rt=45k
-
-
150
-
-
191
2
0.5
232
-
-
Hz
V
V
Vcth
Vbctl
-
-
93
89
-
-
100
100
1.95
0.5
107
111
-
-
kHz
kHz
V
V
∆V25load
∆V25line
V25
0
≤
I25
≤
3mA
7.4V
≤
V
CC
≤
20V
-
-
-
2.44
2
2
2.49
25
25
2.54
mV
mV
V
Symbol
Test Condition
Min.
Typ.
Max.
Unit
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
