LX1686CPW-TR [MICROSEMI]
Fluorescent Light Controller, 256kHz Switching Freq-Max, PDSO24, LEAD FREE, PLASTIC, TSSOP-24;
| 型号： | LX1686CPW-TR |
| 厂家： | 
Microsemi |
| 描述： | Fluorescent Light Controller, 256kHz Switching Freq-Max, PDSO24, LEAD FREE, PLASTIC, TSSOP-24 控制器 |
| 文件： | 总5页 (文件大小：140K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RangeMAXTM
LX1686
DI G I TA L DI M M I N G CCFL CO N T R O L L E R IC
T H E I N F I N I T E P O W E R O F I N N O V A T I O N
P R E L I M I N A R Y D A T A S H E E T
DESCRIPTION
KEY FEATURES
■ RangeMAXTM Wide Range Dimming (>100:1)
■ Synchronizable To Display Video Frequency
■ High Voltage Feedback Loop Directly
Controls Maximum Open Lamp And
Minimum Strike Voltages
■ Transformer Protected From Over-Heating
During Lamp Striking
■ Micro-Amp Sleep Mode
■ User-Programmable Fixed Frequency
Operation
■ Under-Voltage Lockout Feature With Power-
Up Reset
■ Built-In Soft-Start Feature
■ Operates With 3.3V or 5V Power Supplies
■ 100mA Output Drive Capability
The LX1686 Backlight Controller IC
provides all the control functions needed
to implement Linfinity’s direct drive in-
verters used to operate cold cathode fluo-
rescent lamps (CCFL’s). This IC can be
used to control single or multiple-lamp
configurations. CCFL’s are used for back
or edge lighting of liquid crystal flat panel
displays (LCD’s) and typically find appli-
cation in notebook computers, web
browsers, automotive and industrial in-
strumentation, and entertainment sys-
tems.
The LX1686 includes a PWM con-
trolled lamp current burst circuit that
can provide a >100:1 dimming range from
a simple zero to 2.5V potentiometer in-
put. The PWM dimming burst rate is
easily synchronized to the LCD panel’s
frame rate to prevent interference from
optical beat frequencies.
Safety and reliability features in-
clude a new dual feedback contol loop
that permits regulation of maximum lamp
strike voltage as well as lamp current.
Regulating maximum lamp voltage per-
mits the designer to provide for ample
worst case lamp strike voltage while at
the same time conservatively limit maxi-
mum open circuit voltage.
An innovative new strike voltage
generation techniqueenables the mod-
ule designer to optimize high voltage
transformer design for maximum oper-
ating efficiency with no power dissipat-
ing overhead to guarantee strike capa-
bility.
Direct drive topology is a non-reso-
nant, oscillator-controlled PWM regu-
lation method. The LX1686 allows a
wide choice of fixed operating frequen-
cies to match lamp current frequency to
the lamp’s most efficient operating point,
and to minimize high frequency interfer-
ence.
APPLICATIONS
■ Notebooks
■ Instrumentation Displays
■ Desktop Computer Monitors
■ Low Ambient Light Displays (used in
Aircraft, Automobiles, and Hand-held
Equipment)
BENEFITS
■ Extemely High Efficiency From 3.3V or 5V
Power Supplies
■ Lower Cost Than Conventional Buck / Royer
Inverter Topologies
■ Improved Lamp Strike Capability
■ Improved Over-Voltage Control
NOTE: For current data & package dimensions, visit our web site: http://www.linfinity.com.
PRODUCT HIGHLIGHT
RANGEMAX VS. ANALOG DIMMING
Light emitted by a CCFL is proportional to the current
flowing through it. There are two ways to control the
current: by adjusting the amplitude of a continuous AC
current; or, as with RangeMAX technology, by varying
the amount of time a burst of full current is present.
RangeMAX technology frees the backlight inverter
module designer to operate in a lower brightness and
lower power consumption mode than is possible with
conventional amplitude control methods.
5
4
3
2
1
Standard Analog
Dimming Inverter
LinFinity's
RangeMAX
0
30
45
60
75
90
105
Light Output (Nits)
PACKAGE ORDER INFO
Plastic TSSOP
24-pin
TA (°C)
PW
0 to 85
LX1686CPW
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX1686CPWT)
L I N F I N I T Y M I C R O E L E C T R O N I C S I N C .
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
Copyright © 2000
Rev. 0.4 1/00
1
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LX1686
DI G I TA L DI M M I N G CCFL CO N T R O L L E R IC
P R E L I M I N A R Y D A T A S H E E T
ABSOLUTE MAXIMUM RATINGS (Note 1)
PACKAGE PIN OUTS
Supply Voltage (VDD, VDD_P) .........................................................................6.5V
DigitalInputs .................................................................................. -0.3 to VDD+0.5V
AnalogInputs .................................................................................. -0.3 to VDD+0.5V
DigitalOutputs ................................................................................ -0.3 to VDD+0.5V
AnalogOutputs ............................................................................... -0.3 to VDD+0.5V
OperatingJunctionTemperature
Plastic (DB, PW Packages) .......................................................................... 150°C
Storage Temperature Range ..............................................................-65°C to 150°C
Lead Temperature (Soldering, 10 seconds) .................................................... 300°C
AOUT
VSS_P
1
24
23
22
21
20
19
18
17
16
15
14
13
BOUT
VDD_P
VDD
2
VSS
3
4
AFD_C
RAMP_C
RAMP_R
FVERT
TRI_C
OLSNS
ISNS
5
6
7
ICOMP
VSNS
VCOMP
BRT
8
PD_CR
VCO_C
BRT_POS
BRITE
9
10
11
12
I_R
DIG_DIM
ENABLE
Note 1. Exceeding these ratings could cause damage to the device. All voltages are with
respect to Ground. Currents are positive into, negative out of the specified
terminal.
PW PACKAGE
(Top View)
THERMAL DATA
PW PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
100°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the recommended operating conditions of TA = 0 to 85°C, VDD=VDD_P= 3.0 to 5.5V)
(Ri = 40kΩ, CVCO= 0.01µF, CAFD= 0.22µF, CTRI= 0.83µF, CRAMP= 208pF, RRAMP = 15kΩ, CPD= 0.22µF, CPDC= 0.047µF, RPD= 110kΩ.)
LX1686
Min. Typ.
Parameter
Symbol
Test Conditions
Units
Max.
Power Supply Voltage
Operating Current
VDD
IDD
VDD = VDD_P
VDD = VDD_P = 5V
3
5.5
7
5.5
10
2.9
V
mA
V
mA
V
5
Power Supply Voltage
VDD_P VDD = VDD_P
3
2
Output Buffer Operating Current
UVLO Threshold
IDD_P
Volsns = VDD = VDD_P = 5V, CA = CB = 1000pF
2.7
160
VTH_UVLO
VH_UVLO
mV
UVLO Hysteresis
Direct Drive Ramp Block
Triangular Wave Generator Analog Output Peak Voltage
Triangular Wave Generator Analog Output Valley Voltage
Triangular Wave Generator Oscillation Frequency
Triangular Wave Generator Oscillation Charge Current
VP_TRI
VV_TRI
F_TRI
2.25
0.75
10
-2.55
2.65
2.25
0.75
1.5
1.65
100
200
300
45
V
V
Hz
µA
µA
V
-2.3
2.3
-2.9
2.9
ICHG_TRI
Tri_c = 0V
Triangular Wave Generator Oscillation Discharge Current IDISCHG_TRI Tri_c = 3V
Ramp Generator Analog Output Peak Voltage
Ramp Generator Analog Output Valley Voltage
Ramp Frequency Change Threshold
VP_RAMP
V
VV_RAMP
1.4
1.55
84
1.65
1.8
116
256
360
V
V
VTH_RAMP_R VDD = 3V
VDD = 5.5V
KHz
KHz
mV
mV
µS
Ramp Generator Oscillation Frequency - Nominal
Ramp Generator Oscillation Frequency - Maximum
OLSNS Threshold Voltage
FRAMP
VTRI_C = 1.4V
170
250
FRAMP_HI VTRI_C = 2.25V
VTH_OLSNS VDD = 3V
VH_OLSNS VDD = 3V
TD_OLSNS GBD
OLSNS Hysteresis
1
OLSNS-to-ICOMP Propagation Delay
Copyright © 2000
Rev. 0.4 1/00
2
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LX1686
DI G I TA L DI M M I N G CCFL CO N T R O L L E R IC
P R E L I M I N A R Y D A T A S H E E T
ELECTRICAL CHARACTERISTICS (continued)
LX1686
Min. Typ.
Parameter
Symbol
Test Conditions
Units
Max.
Digital Dimmer Block
FVERT Input Frequency Capture Range
FVERT Logic Threshold
FR_FVERT
40
200
Hz
V
kΩ
V
VTH_FVERT Design Reference Only
VDD/2
50
2.5
FVERT Input Resistance
RFVERT
VP_VCO
VV_VCO
Design Reference Only
VCO Analog Output Peak Voltage
VCO Analog Output Valley Voltage
VCO Forced Source Current
Forced VCO Oscillation Frequency
Auto-Frequency Detection Response
BRITE Voltage Range
0.65
-5.8
250
V
-6.4
-5.2
µA
Hz
ms
V
FR_VCO_I_SRC VPD_CR = 3V, VDD = 3V
FX_VCO
TD_AFD
VR_BRITE
AFC_C = 0V, CVCO = 0.01µF
1000
FVERT Frequency is 200Hz, VDD = 3V
0
VDD
2.65
2.65
0.65
0.65
2.35
2.35
0.35
0.35
2.5
2.5
0.5
V
Full-Brightness Brite Input Voltage
VBRITE_FULL VBRT_POS = VDD or float; BRITE = 2.5V
VBRT_POS = 0V, BRITE = 0.5V
V
V
V
Full-Darkness Brite Input Voltage
VBRITE_DARK VBRT_POS = VDD or float BRITE = 0.5V
VBRT_POS = 0V, BRITE = 2.5V
0.5
300
VDD/2
VDD/2
ns
V
V
BRITE-to-ICOMP Propagation Delay
BRITE_POS Logic Threshold
DIG_DIM Logic Threshold
Direct Drive PWM Block
ISNS Threshold Voltage Range
VAMP Transconductance
TD_BRITE
VR_ISNS
GM_VAMP VCOMP = 1.25V
IS_VAMP VCOMP = 1.5V
DIG_DIM = VDD
0
2.5
V
µmho
µA
µA
V
400
50
70
VAMP Output Source Current
VAMP Output Sink Current
VAMP Output Voltage Range
VSNS Threshold Voltage
10
20
0
110
120
VDD
1.38
10
700
-80
100
VDD
ISK_VAMP VCOMP = 1.5V
VR_VAMP
1.12
0.8
70
-15
20
0
1.25
1.5
200
-40
60
V
VTH_VSNS VCOMP = VSNS
ID_VCOMP VCOMP = 0.5V, VDD = 3V
GM_IAMP BRITE = 0.5 - 2.6V
mA
µmho
µA
µA
V
VCOMP Discharge Current
IAMP Transconductance
IAMP Output Source Current
IAMP Output Sink Current
IAMP Output Voltage Range
IAMP Input Offset Voltage
VCMP Input Offset Voltage
VCOMP-to-Output Propagation Delay
ICMP Input Offset Voltage
ICOMP-to-Output Propagation Delay
Output Buffer Block
IS_IAMP
ISK_IAMP
VR_IAMP
TSS
ICOMP = 1.5V, VDD = 3V
ICOMP = 1.5V, VDD = 3V
40
3
250
3
ms
mV
ns
CVCOMP = 1µF
-10
-10
10
500
10
VOS_VCMP VCOMP = 1.25V, VDD = 3V
TD_VCOMP VDD = 3V
mV
ns
VOS_ICMP ICOMP = 0.5 to 2.25V, VDD = 3V
TD_ICOMP BRITE = 1.25V, RAMP_C = 2V, VDD = 3V
1100
Output Sink Current
ISK_OUTBUF AOUT, BOUT = VDD = 3V
AOUT, BOUT = 1V, VDD = 3V
25
20
-35
-20
45
35
-50
-40
80
55
-80
-55
mA
mA
mA
mA
Output Source Current
IS_OUTBUF AOUT, BOUT = 0V, VDD = 3V
AOUT, BOUT = 2V, VDD = 3V
Bias Control Block
Voltage at Pin I_R
VIR
0.98
1.02
V
µA
kΩ
V
Pin I_R Maximum Source Current
VBG Output Resistance
IMAX_IR
RO_VBG
VEN3V
Design Reference Only
Design Reference Only
VDD = 3V
50
10
1.9
3.2
0.45
350
1.5
2.7
2.4
3.6
ENABLE Logic Threshold - 3V
ENABLE Logic Threshold - 5.5V
ENABLE Threshold Hysteresis - 3V
ENABLE Threshold Hysteresis - 5.5V
V
VEN5.5
VDD = 5.5V
V
mV
VH_EN3
VH_EN5.5
Copyright © 2000
Rev. 0.4 1/00
3
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LX1686
DI G I TA L DI M M I N G CCFL CO N T R O L L E R IC
P R E L I M I N A R Y D A T A S H E E T
FUNCTIONAL PIN DESCRIPTION
Pin
Number
Pin
Designator
Description
1
2
3
4
AOUT
VSS_P
VSS
Output driver A.
Power ground for output drivers only.
Signal ground.
AFD_C
Connects to an external cap, CAFD. Forcing to ground or VDD will make the VCO oscillate at approximately
50% of the maximum VCO frequency. Forcing to VDD/2 will make the VCO oscillate at 2x the FVERT
frequency.
5
6
RAMP_C
RAMP_R
FVERT
Connects to external capacitor CRAMP for setting Direct Drive PWM operating frequency.
Connects to external resistor RRAMP for setting Direct Drive PWM operating frequency.
Vertical frequency reference digital input. Has internal pull down.
7
8
PD_CR
Phase Detector Filter. Part of phase lock loop. Connects to external capacitor and resistor network.
9
VCO_C
BRT_POS
Connects to external capacitor CVCO.
10
Brightness control polarity. Has internal pullup. Leave open or pull up to VDD for dimming brightness
proportional to BRITE voltage, connec to ground for brightness inversely proportional to BRITE voltage.
11
12
BRITE
Analog voltage input for brightness control.
DIG_DIM
Digital Dimming Enable internal pullup. Leave open or pull up to VDD for operating in digital dimming
mode. Connect to ground for analog dimming mode.
13
14
15
16
ENABLE
I_R
Chip Enable internal pullup. High enables the chip. Low disables.
Current Reference Resistor. External resistor to ground (Ri) determines internal capacitor CICOMP
Current Error Amplifier non-inverting input.
.
BRT
VCOMP
Voltage Error Amplifier output. Connects to external frequency compensation capacitor CVCOMP. Controls
soft-start timing.
17
18
19
20
21
22
23
24
VSNS
ICOMP
ISNS
Voltage Error Amplifier inverting input.
Current Error Amplifier output. Connects to external frequency compensation capacitor CICOMP
.
Current Error Amplifier inverting input.
OLSNS
TRI_C
VDD
Open Lamp Sense Input.
Connects to external capacitor CTRI for setting strike frequency ramp slope.
VDD
VDD_P
BOUT
Dedicated VDD for output buffers only.
Output driver B.
Copyright © 2000
Rev. 0.4 1/00
4
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
RangeMAXTM
LX1686
DI G I TA L DI M M I N G CCFL CO N T R O L L E R IC
P R E L I M I N A R Y D A T A S H E E T
BLOCK DIAGRAM
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FIGURE 1 — LX1686 Block Diagram
RangeMAX and is a trademark of Linfinity Microelectronics Inc.
PRELIMINARY DATA - Information contained in this document is pre-production data, and is proprietary to LinFinity. It may
not modified in any way without the express written consent of LinFinity. Product referred to herein is offered in sample form
only, and Linfinity reserves the right to change or discontinue this proposed product at any time.
Copyright © 2000
Rev. 0.4 1/00
5
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