Fairchild FAN7315G Lcd back light inverter drive ic Datasheet

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FAN7315
LCD Back Light Inverter Drive IC
Features
Description
• 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
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
OUTA
OSCILLATOR
Output
Driver
OUTB
Output
Control
Logic
CT
-
5.2uA
S_S
PGND
OUTC
+
+
Output
Driver
OUTD
EA_OUT
Thermal
protection
ADIM
+
EA_IN
-
Error Amp.
Q
Solr
240uA
Sburst
Q
SET
CLR
UVLO
R
S
-
OLP
300mV
+
240uA
+
SCP
+
2V
BCT
Solr
-
OLR
Voltage
Reference
&
Internal
Bias
+
-
+
2
ENA
1.4V
VIN
VIN
+
UVLO
-
AGND
REF
Sburst
BDIM
2V
2.5VREF
UVLO 7.4V
FAN7315
Pin Assignments
SCP
OUTB
20
19
OUTA
VIN
PGND
18
17
16
OUTC OUTD
15
14
CT
RT
13
12
11
10
BCT
FAN7315
1
OLP
2
3
OLR
ENA
4
S_S
6
7
8
9
REF
ADIM
BDIM
EA_IN
5
AGND
EA_OUT
Pin Definitions
No
Name
1
OLP
2
3
Function Description
No
Name
Function Description
Open Lamp Protection
11
BCT
OLR
Open Lamp Regulation
12
RT
Timing Resistor
ENA
Enable Input
13
CT
Timing Capacitor
4
S/S
Soft Start
14
OUTD
NMOSFET Drive Output D
5
AGND
Analog Ground
15
OUTC
PMOSFET Drive Output C
6
V25
2.5V Reference Voltage
16
PGND
Power Ground
Supply Voltage
Burst Dimming Timing Capacitor
7
ADIM
Analog Dimming Input
17
VIN
8
BDIM
Burst Dimming Input
18
OUTA
PMOSFET Drive Output A
9
EA_IN
Error Amplifier Input
19
OUTB
NMOSFET Drive Output B
10
EA_OUT
Error Amplifier Output
20
SCP
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
Symbol
Value
Unit
Supply Voltage
VCC
7.4 ~ 20
V
Operating Temperature Range
Topr
-40 ~ 85
°C
Storage Temperature Range
Tstg
-65 ~ 150
°C
Thermal Resistance Junction-Air (Note1,2)
RθJA
112
°C/W
Pd
1.1
W
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
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
Symbol
Test Condition
Min.
Typ.
Max.
Unit
Load Regulation
∆V25load
0 ≤ I25 ≤ 3mA
-
2
25
mV
Line Regulation
∆V25line
7.4V ≤ VCC ≤ 20V
REFERENCE SECTION
-
2
25
mV
V25
-
2.44
2.49
2.54
V
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
150
191
232
Hz
2.5V Regulation Voltage
OSCILLATOR SECTION(MAIN)
OSCILLATOR SECTION(BURST)
Oscillation Frequency
foscb
Ctb = 6.8nF, Rt=45k
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
2.2
2.5
2.8
V
3.5
5.2
6.9
uA
EA_OUT High Volgate
Vea_outh
SOFT START SECTION
Soft Start Current
Soft Start Clamping Voltage
Iss
S_S=0V
Vssh
-
2.2
2.55
2.9
V
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
Start Threshold Voltage On
Vthon
-
5.2
6.3
7.4
V
UVLO Hysteresis
Vhys
-
100
300
500
mV
48
85
122
uA
-
-
2
mA
55
80
105
uA
PROTECTION SECTION
UNDER VOLTAGE LOCK OUT SECTION
Start Up Current
Ist
VCC = Vth-0.2V
Operating Supply Current
Iop
VCC = 12V
Stand-by Current
Isb
VCC = 12V, ENA=0V
5
FAN7315
Electrical Characteristics (Continued)
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
Off State Input Voltage
Voff
-
-
-
0.7
V
On State Input Voltage
Von
-
2.1
-
-
V
V
ON/OFF SECTION
OUTPUT SECTION
PMOS Gate High Voltage
Vpdhv
VCC =12V
-
Vcc
-
PMOS Gate Low Voltage
Vpdlv
VCC =12V
Vcc7.25
Vcc-6.5
Vcc5.55
NMOS Gate High Voltage
Vndhv
VCC = 12V
5.55
6.5
7.25
NMOS Gate Low Voltage
Vndlv
VCC =12V
PMOS Gate Voltage With UVLO
Activated
Vpuv
VCC = Vth-0.5V
Vcc-0.2
-
-
NMOS Gate Voltage With UVLO
Activated
Vnuv
VCC = Vth-0.5V
-
-
0.2
V
0.2
V
Rising Time(Note1)
Tr
VCC = 12V, Cload=1700pF
-
100
300
ns
Falling Time(Note1)
Tf
VCC = 12V, Cload=1700pF
-
100
300
ns
Min. Overlap between diagonal
switches(Note1)
fosc=100KHz
-
0
-
%
Max. Overlap betwwen diagonal
switches(Note1)
fosc=100KHz
-
100
-
%
PDR_A/NDR_B(Note1)
fosc=100KHz, Rt=45k
-
325
-
ns
PDR_C/NDR_D(Note1)
fosc=100KHz, Rt=45k
-
325
-
ns
Max./Min Overlap
Delay Time
Note:
1. These parameters, although guaranteed, are not 100% tested in production.
6
FAN7315
Mechanical Dimensions
Package
Dimensions in millimeters
20-SSOP
7
FAN7315
Ordering Information
Product number
Package
Operating Temperature
FAN7315G
20-SSOP
-40°C ~ 85°C
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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