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LX1688IPW

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
RangeMAX™ LX1688
PRODUCTION DATA SHEET
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
Copyright © 2001
Rev. 1.2, 2006-03-09
WWW.Microsemi .COM
Multiple Lamp CCFL Controller
TM
®
DESCRIPTION
The LX1688 is a fixed frequency, dual
current/voltage mode, switching regulator
that provides the control function for Cold
Cathode Fluorescent Lighting (CCFL).
This controller can be used to drive a
single lamp, but is specifically designed
for multiple lamp LCD panels. The IC can
be configured as a master or slave and
synchronize up to 12 controllers.
The LX1688 includes highly integrated
universal ‘PWM or DC’ dim input that
allows either a PWM or DC input to adjust
brightness without requiring external
conditioning, since a single external
capacitor CPWM can be used to integrate
a PWM input. Burst mode dimming is
possible if the user supplies a low
frequency PWM signal on the BRITE
input and no CPWM capacitor is used. The
controller utilizes Microsemi’s patented
direct drive fixed frequency topology and
patented resonant lamp strike generation
technique.
Safety and reliability features include a
dual feedback control loop that permits
regulation of maximum lamp strike voltage
as well as lamp current. Regulating
maximum lamp voltage permits the designer
to provide for ample worst-case lamp strike
voltage while conservatively limiting
maximum open circuit voltage. In addition
the controller features include auto
shutdown for an open or broken lamp, and a
lamp fault detection with a status reporting
output.
To improve design flexibility the IC
includes the ability to select the polarity of
both the chip enable and dim (BRITE)
inputs. Also included is a switched VDD
output of up to 10mA that will allow the
user to power other circuitry that can be
switched on and off with the inverters
enable input. This preserves the micro
power sleep mode with no additional
components.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
Protected by U.S. Patents 5,615,093; 5,923,129; 5,930,121; 6,198,234; Patents Pending
KEY FEATURES
Provision to Synchronize Lamp
Current & Frequency With Other
Controllers
Dimming With Analog or Digital
(PWM) Methods (>20:1)
Programmable Fixed Frequency
Adjustable Power-up Reset
ENABLE/BRITE Polarity Selection
Voltage Limiting on Step-up
Transformer Secondary Winding
Open Lamp Timeout Circuitry
Switched VDD Output (10mA)
Micro-Amp Sleep Mode
Operates With 3.3V to 5V Supply
100mA Output Drive Capability
APPLICATIONS / BENEFITS
Desktop LCD Monitors
Multiple Lamp Panels
Low Ambient Light Displays
High Efficiency
Lower Cost than Conventional
Buck/Royer Inverter Topologies
Improved Lamp Strike Capability
Improved Over-Voltage Control
PRODUCT HIGHLIGHT
12
24
13
LX1688
MASTER
FETS
12
24
13
LX1688
SLAVE
FETS
FAULT 1
FAULT 2
RAMP RESET
PHASE SYNC
INPUT
CONNECTOR
LAMPS
DIMMING (BRITE)
ENABLE
BRITE
ENABLE
FAULT 1
FAULT 2
VDD
STRIKE
STATUS
STRIKE
STATUS
Ch2
10.0mV Ω
M
100µs
Ch3
10.0mV Ω
125 Hz 5% Duty cycle Burst
65KHz run frequency
Simplified Quad Lamp Inverter Showing Synchronized Output Waveforms
PACKAGE ORDER INFO
PW
Plastic TSSOP
24-Pin
T
J
(°C)
M
IN V
DD
MAX V
DD
RoHS compliant / Pb-free Transition DC: 0442
0 to 70 3.0V 5.5V
LX1688CPW
-40 to 85 3.0V 5.5V
LX1688IPW
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1688CPW-TR)
L
L
X
X
1
1
6
6
8
8
8
8
RangeMAX™ LX1688
PRODUCTION DATA SHEET
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
Copyright © 2001
Rev. 1.2, 2006-03-09
WWW.Microsemi .COM
Multiple Lamp CCFL Controller
TM
®
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VDD_P, VDD)................................................................................ 6.5V
Digital Inputs ................................................................................... -0.3V to VDD +0.5V
Analog Inputs.................................................................................. –0.1V to VDD +0.5V
Digital Outputs................................................................................. -0.3V to VDD +0.5V
Analog Outputs ................................................................................ -0.1V to VDD +0.5V
Maximum Operating Junction Temperature ............................................................150°C
Storage Temperature................................................................................. -65°C to 150°C
Peak Package Solder Reflow Temp. (40 seconds max. exposure) ................260°C(+0.-5)
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.
THERMAL DATA
PW
Plastic TSSOP 24-Pin
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ
JA
100°C/W
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x θ
JA
).
The θ
JA
numbers are guidelines for the thermal performance of the device/pc-board system. All of the
above assume no ambient airflow.
PACKAGE PIN OUT
BEPOL
VDD
A
OUT
2
3
4
5
6
7
8
9
10
11
12
1
23
22
21
20
19
18
17
16
15
14
13
24
VSS_P
BRITE
CPOR
ENABLE
I_R
CPWM1
CPWM2
RMP_RST
PHA_SYNC
VDD_P
VDDSW
TRI_C
OLSNS
ISNS
ICOMP
VCOMP
VSNS
SLAVE
FAULT
B
OUT
VSS
PW PACKAGE
(Top View)
RoHS / Pb-free 100% matte Tin Lead Finish
FUNCTIONAL PIN DESCRIPTION
Pin Name Description Pin Name Description
A
OUT
Output Driver A B
OUT
Output Driver B
VSS_P
Connects to dedicated GND for Aout and Bout
Drivers
VDD_P
Connects to dedicated VDD for Aout and Bout
Drivers
VSS Connects to analog GND VDD Connects to analog VDD
BEPOL
Tri-mode input pin to control the polarity of the
ENABLE and BRITE signal
VDDSW Switchable VDD output controlled by ENABLE
BRITE Analog/PWM input for brightness control TRI_C Connects to external capacitor C
TRI
CPOR
Connects an external capacitor C
POR
to VDD and
is used for setting power-up reset pulse width.
OLSNS Analog input to detect open-lamp condition
ENABLE Used to enable or disable the chip ISNS
Analog input from lamp current, has built-in 300mv
offset
I_R
Connects to external resistor R
I
; for bias current
setting for internal oscillator
ICOMP
Current error Amp’s output; connects to external
capacitor C
ICOMP
CPWM1
Connects to external capacitor C
PWM
, used for
integrating an external digital PWM signal for
analog dimming
VCOMP
Voltage error Amp’s output; connects to external
capacitor C
VCOMP
, can be used for soft-start
CPWM2
Connects to external capacitor C
PWM
, used for
integrating an external digital PWM signal for
analog dimming.
VSNS Analog input from transformer output voltage
RMP_RST
If SLAVE = “0”, RMP_RST is a CMOS output; if
SLAVE = “1”, it is a CMOS input that locks the
ramp oscillation frequency to the master clock
SLAVE
Input control pin for setting the IC either in Master
or Slave mode; “1” for slave mode and “0” for
master mode.
PHA_SYNC
If SLAVE= “0”, PHA_SYNC is a CMOS output; if
SLAVE = “1”, it is a CMOS input that make the
A
OUT
/B
OUT
phase synchronous with the master
FAULT
Digital output to indicate maximum number of lamp
striking attempts has occurred without lamp
ignition.
P
P
A
A
C
C
K
K
A
A
G
G
E
E
D
D
A
A
T
T
A
A
RangeMAX™ LX1688
PRODUCTION DATA SHEET
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
Copyright © 2001
Rev. 1.2, 2006-03-09
WWW.Microsemi .COM
Multiple Lamp CCFL Controller
TM
®
RECOMMENDED OPERATING CONDITIONS
LX1688
Parameter
Min Typ Max
Units
Supply Voltage (V
DD
,V
DDP
) 3 5.5 V
BRITE Linear DC Voltage Range 1 2.5 V
BRITE PWM Logic Signal Voltage Range 0 V
DD
V
Digital Inputs (SLAVE, PHA_SYNC, RMP_RST, BEPOL, ENABLE ) 0 V
DD
V
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, specifications apply over the range: T
A
=-40 to 85
O
C, V
DD
(For LX1688IWP) & T
A
= 0 to 70
O
C, V
DD
(For
LX1688CWP), V
DD_P
= 3.0 to 5.5V. R
I
= 80Kohms, C
TRI
= 0.083µF
LX1688
Parameter Symbol Test Conditions
Min Typ. Max
Units
DIMMER
V
BRITE_MAX
V
BEPOL
= V
DD
2.6 2.5
Conventional¹ Dimming
BRITE Input Voltage
V
BRITE_MIN
V
BEPOL
= V
DD
0.4 0.5
V
V
BRITE_MAX
V
BEPOL
= V
SS
or float 0.4 0.5
Reverse Dimming
BRITE Input Voltage
V
BRITE_MIN
V
BEPOL
= V
SS
or float 2.6 2.5
V
Max Brightness V
BRT
Voltage V
BRT_FULL
V
BEPOL
= V
SS
, V
BRITE
= 0.4V 1.90 2.0 2.05 V
Full-darkness V
BRT
voltage V
BRT_DARK
V
BEPOL
= V
SS
, V
BRITE
= 2.6V 0 0.05 V
ISNS input threshold voltage V
TH_IAMP
T
A
= 0 to 70
O
C 150 300 450 mV
ISNS input threshold voltage V
TH_IAMP
T
A
= -40 to 85
O
C 150 300 550 mV
BRITE-to-ICOMP propagation delay T
D_BRITE
2 µS
STRIKE AND RAMP GENERATOR
Max. number of strike before fault N
FAULT
63
Triangular Wave Generator Analog Output
Peak Voltage
V
P_TRI
2.3 2.5 2.6 V
Triangular Wave Generator Analog Output
Valley Voltage
V
V_TRI
0.15 0.3 0.40 V
Triangular Wave Generator Oscillation
Frequency
F
_TRI
7 10 13 Hz
Max. Lamp Strike Frequency F
MAX_STK
F
MAX_STK
= F
LAMP
X ~2.5 150 195 KHz
Lamp Run Frequency F
LAMP
V
OLSNS
> 0.65V; VDD=5V
T
A
= 0 to 70
O
C
60 65 70 KHz
Lamp Run Frequency F
LAMP
V
OLSNS
> 0.65V; VDD=5V
T
A
=-40 to 85
O
C
57 65 70 KHz
Lamp Run Frequency regulation over V
DD
F
LAMP_REG
V
OLSNS
> 0.65V 4 6 % /V
OLSNS threshold voltage V
TH_OLSNS
740 790 840 ‘mV
OLSNS hysteresis V
H_OLSNS
540 590 640 ‘mV
OLSNS-to-ICOMP propagation delay T
D_OLSNS
GBNT ² 1 us
Fault, PHA_SYNC, RMP_RST, logic high
threshold
V
H
V
DD
– 0.5 V
Fault, PHA_SYNC, RMP_RST, logic low
threshold
V
L
0.7 1 V
Minimum Fault-pin output current I_FAULT 10 15 ‘mA
¹Conventional polarity means that the lamp brightness increases with increasing voltage on the BRITE pin. Reverse polarity means that brightness decreases with increasing
voltage
² Guaranteed but not production tested
E
E
L
L
E
E
C
C
T
T
R
R
I
I
C
C
A
A
L
L
S
S
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

LX1688IPW

Mfr. #:
Buy LX1688IPW
Manufacturer:
Microchip / Microsemi
Description:
Display Drivers & Controllers
Lifecycle:
New from this manufacturer.
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