lx1688 Microsemi Corporation, lx1688 Datasheet

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lx1688

Manufacturer Part Number
lx1688
Description
Multiple Lamp Ccfl Controller
Manufacturer
Microsemi Corporation
Datasheet
Copyright © 2001
Rev. 1.2, 2006-03-09
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
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.
IMPORTANT: For the most current data, consult MICROSEMI’s website:
Protected by U.S. Patents 5,615,093; 5,923,129; 5,930,121; 6,198,234; Patents Pending
The LX1688 is a fixed frequency, dual
CONNECTOR
INPUT
TM
FAULT 1
FAULT 2
without
DIMMING (BRITE)
ENABLE
requiring
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
ENABLE
MASTER
LX1688
LX1688
SLAVE
VDD
FAULT 2
Simplified Quad Lamp Inverter Showing Synchronized Output Waveforms
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1688CPW-TR)
-40 to 85
FAULT 1
0 to 70
T
BRITE
J
D E S C R I P T I O N
(°C)
external
dual feedback control loop that permits
regulation of maximum lamp strike voltage
as well as lamp current.
maximum lamp voltage permits the designer
to provide for ample worst-case lamp strike
voltage
maximum open circuit voltage. In addition
the
shutdown for an open or broken lamp, and a
lamp fault detection with a status reporting
output.
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.
power sleep mode with no additional
components.
STATUS
STRIKE
STATUS
STRIKE
M
3.0V
3.0V
Safety and reliability features include a
To improve design flexibility the IC
IN
P R O D U C T H I G H L I G H T
P A C K A G E O R D E R I N F O
V
controller
DD
Integrated Products Division
while
®
Microsemi
http://www.microsemi.com
M
This preserves the micro
5.5V
5.5V
AX
features
conservatively
RangeMAX™
V
DD
LAMPS
PW
RoHS compliant / Pb-free Transition DC: 0442
include
Multiple Lamp CCFL Controller
Regulating
limiting
Plastic TSSOP
24-Pin
P
auto
LX1688CPW
RODUCTION
LX1688IPW
125 Hz 5% Duty cycle Burst
65KHz run frequency
Ch3
10.0mV Ω
A P P L I C A T I O N S / B E N E F I T S
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
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
D
ATA
K E Y F E A T U R E S
Ch2
S
HEET
10.0mV Ω
M
100µs
LX1688
Page 1

Related parts for lx1688

lx1688 Summary of contents

Page 1

... Simplified Quad Lamp Inverter Showing Synchronized Output Waveforms T (° - Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1688CPW-TR) Copyright © 2001 Rev. 1.2, 2006-03-09 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 RangeMAX™ ® ...

Page 2

... VDD and POR OLSNS ISNS ; for bias current I ICOMP , used for PWM VCOMP , used for PWM VSNS SLAVE FAULT Microsemi Integrated Products Division LX1688 RODUCTION ATA HEET OUT VSS_P 2 23 VSS 3 22 ...

Page 3

... Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 RangeMAX™ ® Multiple Lamp CCFL Controller Parameter =- (For LX1688IWP) & 0.083µF TRI Symbol Test Conditions V V ...

Page 4

... V ) BEPOL 2.5V ENABLE I DD_SLEEP ( BEPOL SS V Rising turn-on threshold TH_UVLO V Falling turn-off hysteresis H_UVLO Microsemi Integrated Products Division LX1688 D S ATA HEET LX1688 Units Min Typ. Max 10 ‘ 100 ‘mA 100 ‘mA 50 ‘mA 50 ‘mA 100 ‘ ...

Page 5

... Power-on-Reset Pulse Width Vs Temperature VDD= - Microsemi Integrated Products Division LX1688 RODUCTION ATA HEET VDD=5.5V VDD=3V - Temperature (°C) Turn On Turn Off - Temperature (° ...

Page 6

... EXT EXT Ramping up / Input: F Input EXT EXT down Input: F Input EXT EXT V DD_P Q A OUT Q B OUT VSS_P 800mV 600mV IGNITE OLSNS TRI WAVE 6 BIT GEN TRI_C COUNTER TTL FAULT BUF FAULT LX1688 Lamp / 2 INT Off / 2 EXT Off Page 6 ...

Page 7

... O F 3.3V / 5.0V I PERATION ROM AND OR The LX1688 is designed to operate and meet all specifications at 3.3V ±10% to 5.0V ±10%. The under voltage lockout is set at nominally 2.8V with a 190mV hysteresis ASTER LAVE LOCK YNCHRONIZATION ...

Page 8

... LEEP ODE IGNAL (VDDSW) Since the LX1688 can be used in portable battery operated systems, a very low power sleep mode is included. The IC will consume less than 10µA quiescent current from both the VDD and VDD_P pins combined, when the ENABLE pin is deactivated. The polarity of the ENABLE pin is programmable by the BEPOL input (see table 1) ...

Page 9

... CPWM2 11 RMP_RST RMP_RST 12 PHA_SYNC PHA_SYNC Figure 1 – Schematic for LX1688 Inverter Module Configured as Master Copyright © 2001 Rev. 1.2, 2006-03-09 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 RangeMAX™ ® Multiple Lamp CCFL Controller ...

Page 10

... I V NPUT OLTAGE The LX1688 controller can operate at 3.3 to 5.0V ±10%, in this application all modules were driven by the same power voltage (a constant 5.0V), which provides VDD for controllers, and input voltage for the power section. Notice that VDD feeds all analog signals and VDD_P feeds only the output driver stage, these two signals should be filtered separately (Figure 1) ...

Page 11

... PHA-SYNC R3a VDDSW 220 Slave 2 R13a LED1a 100K C5b: 220nF 16V 10% C6b: 82nF 16V 10% C7b: 100nF 16V 10% C8b: 2.2nF 50V 5% C9b: 4.7nF 16V 10% C10-11b: 10nF 16V 10% Microsemi Integrated Products Division LX1688 RODUCTION ATA HEET VDD C4 220nF C5 16v 10% Power C7 Output C8 Section ...

Page 12

... Figure 5- OUT Figure 4- Output drivers of both Master and Slaves. CH2=A CH3=A CH4=A Microsemi Integrated Products Division LX1688 D S ATA HEET Master is in striking mode while slaves are in running mode CH2= A (Master), CH3=A (Slave1), OUT OUT ...

Page 13

... Multiple Lamp CCFL Controller P RODUCTION Figure 7- (Master), OUT (Slave2) OUT Microsemi Integrated Products Division LX1688 D S ATA HEET Gate signals during digital dimming with 5% duty cycle CH2= A (Master), OUT CH3=A (Slave1), CH4=A (Slave2 ...

Page 14

... NOVACAP AVX AVX AVX NOVACAP 2.2pF PCB AVX NOVACAP Microsemi turns ratio 1:75 Molex Connector, 2 pin Molex Table 2 - List of material for LX1688 inverter module Microsemi Integrated Products Division LX1688 RODUCTION ATA HEET Part Number LX1688 Si9945AEY BC847ALT1 BAW56 BAV99 ...

Page 15

... C 0.09 0.20 0.0035 D 7.70 7.90 0.303 E 4.30 4.50 0.169 F 0.65 BSC 0.025 BSC G 0.05 0.15 0.002 H – 1.10 – L 0.50 0.75 0.020 M 0° 8° 0° P 6.25 6.55 0.246 *LC – 0.10 – Microsemi Integrated Products Division LX1688 D S RODUCTION ATA HEET C M MAX 0.037 0.012 0.008 0.311 0.177 0.005 .0433 0.030 8° 0.258 0.004 Page 15 ...

Page 16

... Copyright © 2001 Rev. 1.2, 2006-03-09 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 RangeMAX™ ® Multiple Lamp CCFL Controller P RODUCTION Microsemi Integrated Products Division LX1688 D S ATA HEET Page 16 ...

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