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Dual LCD Back Light Inverter Drive IC
Features
* * * * * * * * * * * * * Backlight Lamp Ballast and Soft Dimming Reduce the Number of Components Wide Range Operating Voltage 9-30V Precision Voltage Reference Trimmed to 3.4% Low Standby Current (Typ. 150uA) Soft Start Function Dual PWM Control Analog & Burst Dimming Function P-Channel MOSFET Drive Open Lamp Regulation(OLR) Open Lamp Protection(OLP) Buck+Royer Topology 20 SSOP
FAN7548
Description
The FAN7548 provides the necessary circuit blocks to implement a highly efficient CCFL backlight power supply in a small footpirnt 20 SSOP package. The device features two control stages for operating independent resonant tanks for multi-lamp designs. External parts count is minimized and system cost is reduced by integration such features as a feedback controlled PWM driver stage, the soft start, the open lamp regulation, the open lamp protection, the UVLO, and the self-synchronization circuitry between the buck and Royer stages. It includes an internal shunt regulator, allowing it to operate with input voltage from 9 to 30V. It supports analog and burst dimming modes of operation. It providees the open lamp regulation, and the open lamp protection.
20-SSOP
1
Rev. 1.0.0
(c)2003 Fairchild Semiconductor Corporation
FAN7548
Internal Block Diagram
ENA 3Vref V3 Vz Vcc + UVLO 5.2V GND Vb BDIM Internal Bias Va ADIM
OUT1 13.5V
Output Drive1
Output Drive2 13.5V
OUT2
Vz 2uA OLP1 3.7V 2.5V S COMP1 Q QS COMP6 + R R +
Vz 2uA OLP2 3.7V 2.5V
SOLR1
SBurst1
SBurst2
SOLR2
2.5V
COMP1
Ramp
Css
Ramp
OSC1 COMP2
Sync. Sync.
1.5V
To SOLR1
SOLR2
Max. 1.75V Min. 0.25V
6V
BCT Vb
+ -
COMP5
To SBurst1
Vcc 10uA Css CSS 6.5V
To SBurst2
(Max.+Min.) of BCt + Max. 1.75V
COMP10
+
Min. 0.25V
2
-
+
-
OLR1
COMP3
COMP8
6V
+
-
+ COMP7
+ +
Css Va
+ + + +
VFB1
Error Amp.1 Buffer
COMP4
COMP9 Buffer
Error Amp.2
+ + +
VFB2 Css Va 2.5V
COMP2 OSC2
1.5V
OLR2
FAN7548
Pin Assignments
20
19
18
17
16
15
14
13
12
11
FAN 7 5 4 8
1 2 3 4 5 6 7 8 9 10
Pin Definitions
No 1 2 3 4 5 6 7 8 9 10 Name BDIM BCT OLP1 VFB1 COMP1 OLR1 OSC1 ENA VCC OUT1 Function Description Burst Dimming Input Timing Capacitor for Burst Dimming Open Lamp Protection 1 Error Amp Input 1 Error Amp Output 1 Open Lamp Regulation 1 Main Oscillator 1 ON/OFF Control Input Power Supply Gate Drive Output 1 No 11 12 13 14 15 16 17 18 19 20 Name OUT2 GND CSS OSC2 OLR2 COMP2 VFB2 OLP2 ADIM V3 Function Description Gate Dirve Output 2 Ground Capacitor for Soft Start Main Oscillator 2 Open Lamp Regulation 2 Error Amp Output 2 Error Amp Input 2 Open Lamp Protection 2 Analog Dimming Input 3V Reference Voltage
3
FAN7548
Absolute Maximum Ratings
Vcc=12V, Ta=25C for typical values and -25C Ta 85C and 9V Vcc 30V for min/max values, 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 VCC Topr Tstg RJA Pd
Value 6~30 -25 ~ 85 -65 ~ 150 112 1.1
Unit V C C C/W W
4
FAN7548
Electrical Characteristics
Vcc=12V, Ta=25C for typical values and -25C Ta 85C and 9V Vcc 30V for min/max values, unless otherwise specified. Characteristics ON/OFF SECTION On Stage Input Voltage SOFT START SECTION Soft Start Charging Current Soft Start Clamping High Voltage UVLO SECTION Start Up Current Start Threshold Voltage Operating Supply Current REFERENCE SECTION 3V Reference Voltage Refrence Voltage ERROR AMP SECTION Output Sink Current Output Source Current BURST OSCILLATOR SECTION Operating Frequency Osc High Voltage Osc Low Voltage PROTECTION SECTION Open Lamp Regulation Voltage Open Lamp Protection Voltage Open Lamp Protection Current OUTPUT SECTION Output High Voltage Output Low Voltage Output Clamping High Voltage Output Voltage with UVLO Activated Rising Time Falling Time Voh Vol Voch Vuv Tr Tf Vcc=12V Vcc=12V VCC = 15V VCC = 4V VCC = 12V VCC = 12V 10 11.5 2 13.5 150 100 0.2 15.5 4 200 150 V V V V ns ns Vor Vpr Ipr 5.5 2 6 2.5 2.5 6.5 3 V V uA Fbosc Vbh Vbl Ct=150n 93 110 1.75 0.25 127 Hz V V lsin lsur COMP=3V COMP=3V 2 -2 mA mA V3 Vref 2.88 2.425 2.98 2.5 3.08 2.575 V V Ist Vst Iop Vcc=12V Vcc=4.5V 4.7 7 100 5.2 10 300 5.7 13 uA V mA Iss Vssh Css=4V 8.5 5.5 10 6.5 11.5 7.5 uA V Von 0.7 1.7 V Symbol Test Condition Min. Typ. Max. Unit
5
FAN7548
Typical Characteristics
1.8
On Stage Input Supply Voltage
11.2
Soft Start Charging Current
1.6
10.5
1.4
Iss[uA]
-60 -40 -20 0 20 40 60 80 100 120 140
Von[V]
1.2
9.8
1.0
9.1
0.8
-60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 1. On Stage Input Supply Voltage
Soft Start Clamping High Voltage
Figure 2. Soft Start Changing Current
Start Up Current
200
7.14
160
6.72
120
Vssch[V]
6.30
Ist[uA]
-60 -40 -20 0 20 40 60 80 100 120 140
80
5.88
40
0 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 3. Soft Start Clamping High Voltage
Startup Thresh hold Voltage
5.6 11.7 5.4 10.4
Figure 4. Start Up Current
Operating Supply Current
13.0
5.2
Iop[mA]
Vst[V]
9.1 5.0
4.8
7.8
-60
-40
-20
0
20
40
60
80
100
120
140
-60
-40
-20
0
20
40
60
80
100
120
140
Temparature['C]
Temparature['C]
Figure 5. Startup Thresh Hold Voltage
Figure 6. Operating Supply Current
6
FAN7548
Typical Characteristics (Continued)
3V Reference Voltage Output Sink Current 1
3.08
3.04
8.5
2.96
Isin1[mA]
3.00
6.8
V3[V]
5.1
2.92
3.4
2.88 -60 -40 -20 0 20 40 60 80 100 120 140 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 7. 3V Reference Voltage
Output Source Current 1
Figure 8. Output Sink Current 1
Output Sink Current 2
-8.5
8.5
Isur1[mA]
Isin2[mA]
-6.8
6.8
-5.1
5.1
-3.4
3.4
-60
-40
-20
0
20
40
60
80
100
120
140
-60
-40
-20
0
20
40
60
80
100
120
140
Temparature['C]
Temparature['C]
Figure 9. Output Source Current 1
Figure 10. Output Sink Current 2
Output Source Current 2
126
Operating Frequency
-8.5 119
Fbosc[Hz]
-60 -40 -20 0 20 40 60 80 100 120 140
Isur2[mA]
-6.8
112
-5.1
105
-3.4
98
-60
-40
-20
0
20
40
60
80
100
120
140
Temparature['C]
Temparature['C]
Figure 11. Output Source Current 2
Figure 12. Operating Frequency
7
FAN7548
Typical Characteristics (Continued)
2.0
OSC High Voltage
0.30
OSC Low Voltage
1.9
0.28
1.8
0.26
Vbh[V]
Vbl[V]
1.7
0.24
1.6
0.22
1.5 -60 -40 -20 0 20 40 60 80 100 120 140
0.20 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 13. OSC High Voltage
Open Lamp Regulation Voltage 1
6.46
Figure 14. OSC Low Voltage
Open Lamp Protection Voltage 1
3.0
6.27
2.8
6.08
2.6
Vor1[V]
Vpr1[V]
5.89
2.4
5.70
2.2
5.51 -60 -40 -20 0 20 40 60 80 100 120 140
2.0 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 15. Open Lamp Regulation Voltage 1
Open Lamp Protection Current 1
6.46
Figure 16. Open Lamp Protection Voltage 1
3.0
Open Lamp Regulation Voltage 2
2.8
6.27
2.6
Ipr1[uA]
6.08
2.4
Vor2[V]
5.89
2.2
5.70
2.0 -60 -40 -20 0 20 40 60 80 100 120 140
5.51 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 17. Open Lamp Protection Current 1
Figure 18. Open Lamp Regulation Voltage 2
8
FAN7548
Typical Characteristics (Continued)
3.0
Open Lamp Protection Voltage 2
3.0
Open Lamp Protection Current 2
2.8
2.8
2.6
2.6
2.4
Ipr2[uA]
-60 -40 -20 0 20 40 60 80 100 120 140
Vpr2[V]
2.4
2.2
2.2
2.0
2.0 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 19. Open Lamp Protection Voltage 2
Output High Voltage 1
Figure 20. Open Lamp Protection Current 2
Output Low Voltage 1
0.8
12.40
0.4
11.78
Voh1[V]
Vol1[V]
0.0
11.16
-0.4
10.54
-0.8
-60
-40
-20
0
20
40
60
80
100
120
140
-60
-40
-20
0
20
40
60
80
100
120
140
Temparature['C]
Temparature['C]
Figure 21. Output High Voltage 1
Output Clamping High Voltage 1
15.00
Figure 22. Output Low Voltage 1
Output Voltage with UVLO Activated 1
4.0
3.8
14.25
3.6
Voch1[V]
13.50
Vuv1[V]
-60 -40 -20 0 20 40 60 80 100 120 140
3.4
12.75
3.2
12.00
3.0 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 23. Output Clamping High Voltage 1
Figure 24. Output Voltage with UVLO Activated 1
9
FAN7548
Typical Characteristics (Continued)
Output High Voltage 2
0.8 12.40 0.4 11.78
Output Low Voltage 2
Voh2[V]
Vol2[V]
-60 -40 -20 0 20 40 60 80 100 120 140
0.0
11.16
-0.4 10.54 -0.8
-60
-40
-20
0
20
40
60
80
100
120
140
Temparature['C]
Temparature['C]
Figure 25. Output High Voltage 2
Figure 26. Output Low Voltage 2
Output Clamping High Voltage 2
15.00
4.0
Output Voltaeg with UVLO Activated 2
3.8
14.25
3.6
Voch2[V]
13.50
Vuv2[V]
-60 -40 -20 0 20 40 60 80 100 120 140
3.4
12.75
3.2
12.00
3.0 -60 -40 -20 0 20 40 60 80 100 120 140
Temparature['C]
Temparature['C]
Figure 27. Output Clamping High Voltage 2
Figure 28. Output Voltage with UVLO Activated 1
10
FAN7548
Mechanical Dimensions
Package Dimensions in millimeters
20-SSOP
11
FAN7548
Ordering Information
Product number FAN7548G Package 20-SSOP Operating Temperature -25C ~ 85C
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.
www.fairchildsemi.com 11/4/03 0.0m 001 Stock#DSxxxxxxxx 2003 Fairchild Semiconductor Corporation
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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