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LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
DESCRIPTION
KEY FEATURES
WWW .Microsemi .C OM
The LX1695 is a general purpose DC to PWM generator with supervisory functions for switched Royer CCFL inverter modules used in single or multiple lamp desktop monitors and LCD TV sets. It integrates a PWM that generates digital (burst mode) dimming from a DC brightness control input, and a protection circuit that shuts off the Royer oscillator if lamp ignition does not occur in a timely manner, or in the event of one or more open lamps. Strike and initial open lamp timeout is user programmable with an external RC, and PWM frequency is programmable with a single external resistor.
The DIM_FREQ pin can also accept an external clock signal to program and/or synchronize the Royer output frequency. This low cost eight pin IC includes under-voltage lockout and a logical ENABLE input that permits shutting down the Royer inverter(s) remotely without removing their power. A single output pin can be expanded with external transistors to drive any number of Royer circuits, giving a single device the ability to control very large displays for LCD TV applications or single lamp panels in notebooks and web tablets. The device is available in either an 8 pin plastic DIP or SOIC package.
Single Resistor Programs Output Frequency Allows External Synchronized PWM Open Lamp Sense Protection Programmable Fault Delay Enable and UV Lockout Preset 3.125% Minimum Output Duty Cycle
APPLICATIONS/BENEFITS
DC to PWM Generator Single or Multi Lamp Designs Desktop Monitors LCD TV Industrial Displays
IMPORTANT: For the most current data, consult MICROSEMI's website:
PRODUCT HIGHLIGHT
Wide Range Dimming For a Fixed Royer Inverter
External CLK Override allows Syncronization Single Resistor sets Programmable Clock Frequency
30 to 600 Hertz x 512
OPTIONAL
DIM_FREQ OLSNS GND ROYER VDD
Open Lamp Detection Input Gated for Royer High Royer Inverter Royer Bias Drive 30 to 600 Hertz VDD Fixed Input Supply 4.5 to 5.5V
ENABLE
Logic High Enable ENABLE
LX1695
FLT_DLY BRITE_IN
BRITE_IN
Duty Cycle Control 0 to 2V = 3% to 100%
Programmable lamp strike interval at power on or enable
LX1695 LX1695
PACKAGE ORDER INFO
TJ (C) -40 to 85
M
Plastic DIP 8-Pin
RoHS / Pb-free
DM
Plastic SOIC 8-Pin
RoHS / Pb-free
LX1695IM
LX1695IDM
Note: Available in Tape & Reel. Append the letters "TR" to the part number. (i.e. LX1695IDM-TR) RoHS compliant.
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
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Supply Voltage (VDD) ........................................................................................6V Inputs (BRITE_IN, OLSNS, FLT_DLY, ENABLE, DIM_FREQ)................. VDD Output Current (ROYER) ...........................................................................150mA
RoHS / Pb-free Peak Package Solder Reflow Temperature (40 seconds Maximum Exposure) .....................................................................................260C (+0, -5) Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of specified terminal.
DIM_FREQ ENABLE FLT_DLY BRITE_IN
1 2 3 4
8 7 6 5
OLSNS GND ROYER VDD
DM Package (Top View)
THERMAL DATA
DIM_FREQ ENABLE FLT_DLY
1 2 3 4
8 7 6 5
OLSNS GND ROYER VDD
M DM
Plastic 8-Pin DIP 85C/W
THERMAL RESISTANCE-JUNCTION AMBIENT, JA
BRITE_IN
Plastic 8-Pin SOIC 163C/W
M Package (Top View) RoHS / Pb-free 100% Matte Tin Lead Finish
THERMAL RESISTANCE-JUNCTION AMBIENT, JA
Junction Temperature Calculation: TJ = TA + (PD x JA). The JA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow.
FUNCTIONAL PIN DESCRIPTION Name VDD GND BRITE_IN Ground Lamp Brightness Control. A DC input of 0 to 2V controls the duty cycle of the Royer output. Zero volts corresponds to minimum duty cycle (3.125%), maximum input voltage must yield 100% duty cycle. BRITE_IN has a high input impedance. Open Lamp Sense Input. This input receives rectified and filtered voltages from each Royer transformer secondary winding that are proportional to lamp current amplitude. These signals are diode OR'ed and compared to 3VDC at the OL_SNS input. If an under limit condition is detected, a fault is declared and the output is turned off. This condition is latched and can only be cleared by cycling the main power input or the ENABLE input signal off and on. Royer Bias Drive Output. This output signal drives external transistors that feed bias currents to one or more oscillators to turn them on. Output drive is totem pole and must be capable of 50mA at 0.4 and 4.0V output when the supply voltage is 4.5 to 5.5 volts. Fault Delay. An external resistor and capacitor at this pin program the time that open lamp fault detection is disabled following power on or an ENABLE low to high transition. By choosing the appropriate resistor and capacitor combination, delay time may be as high as 5 seconds A resistor to ground determines the frequency of the dual slope ramp generator for the digital dimming PWM. This pin may be overdriven through a resistor with totem pole output logic gates to force an external clock to over ride the internal clock, allowing the ROYER output to be synchronized to an external frequency without using another package pin. Input voltage levels of the external pulse are as follows: High state is; 2.9 to 5.5V minus 0.4 volts noise margin for minimum of 2.5 volts. Low state is; 0 to 0.36V plus 0.44 volts for noise margin for total of 0.8 volts. A positive logic level enables the ROYER output pin. A low level turns it off, resets the fault latch and discharges the FLT_DLY capacitor. Logic threshold is about 1.6V. Upon ENABLE going high (True), the fault delay capacitor is allowed to charge, initiating the delay. Description Input Voltage. The IC will be functional and in specifications when this pin is between 4.5 and 5.5VDC.
OL_SNS
ROYER
PACKAGE DATA PACKAGE DATA
FLT_DLY
DIM_FREQ
ENABLE
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
RECOMMENDED OPERATING CONDITIONS Parameter
Supply Voltage (VDD ) BRITE Linear DC Voltage Range DIM_FREQ, ENABLE, FLT_DLY Royer Output Frequency Range
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Min
4.5 0 0 30
LX1695 Typ
Max
5.5 1.95 VDD 600
Units
V V V Hz
250
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, specifications apply over the range: TA=-40 to 85OC, VDD = 4.5 to 5.5V, RDIM_FREQ =25.2K ohms, Royer = 1000pF ENABLE = VDD, BRITE_IN = 1.0V, FLT_DLY = 3V
Parameter
POWER VVDD Dynamic Current Output Off Mode Current Enable Threshold ENABLE Input High Current ENABLE Input Low Current UV Threshold UV Hysteresis ROYER ROYER Output Sink Current ROYER Output Source Current ROYER Output Rise Time ROYER Output Fall Time DIM FREQ DIM_FREQ Voltage DIM_FREQ ISC LOW ROYER Output Frequency NOMINAL ROYER Output Frequency HIGH ROYER Output Frequency DIM_FREQ IIH DIM_FREQ IIL
Symbol
IDD I_OUT OFF VIH VIL_ IIH_ENABLE IIL_ENABLE UV TH
Test Conditions
VDD=5.5V VDD=5.5V; Enable 0.4V
Min
LX1695 Typ
4.0 3.5
Max
Units
mA mA V V A A V mV mA mA nS nS V A Hz Hz Hz A A Hz
2 VDD=5V; ENABLE = 5V VDD=5V; ENABLE = 0V VDD Rising -1 -1 3.7 0.01 -0.01 4 350 75 100 20 20 1 -600 30 250 600 120 -475
DIM_FREQ 512
0.8 1 1 4.3
ISK_ROYER ISRC_ROYER TR TF VDIM_FREQ ISCDIM_FREQ FROYER LOW FROYER NOM FROYER HIGH IIHDIM_FREQ IILDIM_FREQ
BRITE_IN = 2V ROYER = 0.4V BRITE_IN = 2V ROYER = VDD-0.5V COUT = 1000pF COUT = 1000pF
40
100 100
DIM_FREQ = 0V; self limiting RDIM_FREQ = 215K RDIM_FREQ = 25.2K RDIM_FREQ = 10K DIM_FREQ = 3V; No RDIM_FREQ DIM_FREQ = 0.4V; No RDIM_FREQ DIM_FREQ = 15KHz to 300KHz Square Wave
27 237 555
33 263 645
EXT CLK ROYER Output Frequency FROYER EXT_CLK
BRITE_IN / DUTY CYCLE CONTROL BRITE_IN Input High Current IIH_BRITE_IN VDD=5V; BRITE_IN = 2V BRITE_IN Input Low Current IIL_BRITE_IN VDD=5V; BRITE_IN = 0V Duty Cycle 0 DC0 BRITE_IN = 0V; Duty Cycle 1 DC1 BRITE_IN = 1V Duty Cycle 2 DC1 BRITE_IN = 1.95 VDAC Ramp Valley Voltage VDACRP For reference only VDAC Ramp Peak Voltage VDACRV For reference only OLSNS / FAULT DELAY THRESHOLD OLSNS Threshold Voltage VTH_OLSNS OLSNS Clock Cycle Delay OLSNSDY Note 1 FLT_DLY Threshold FLT_DLYTH Note 1 : If duty cycle is set to less than 10% open lamp sensing is internally disabled
-1 -1 2.5 95
0.01 -0.01 3.125 52 100 40 1.9 3 48 2.1
1 1 5
A A % % % mV V `V cycles V
ELECTRICALS ELECTRICALS
2.92
3.05
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
SIMPLIFIED BLOCK DIAGRAM
WWW .Microsemi .C OM
ENABLE
Enable
UVLO
PwrBad
Bias Generator
3V 1V 2.1V
Enable PwrBad Fault Latch
R Q S
NoFault
Ignore_OLSNS PWM
OLSNS
3V
48 Count Ignore fault Logic 9 Bit Dual Ramp DAC 2V 0V
Clock PwrBad
Clock
BRITE_IN
PWM
3.125% Min Duty Cycle
VDD PwrBad
FAULT_ DLY
Ignore_OLSNS 2.1V
NoFault
Power Buffer
ROYER
Enable PwrBad Enable
Internal Clock Generator
BLOCK DIAGRAM BLOCK DIAGRAM
1V
A B
MUX OUT SEL
Clock
DIM_FREQ
External Clock Detector
Figure 1 - Simplified Block Diagram
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
APPLICATION CIRCUIT
L1 F1 CN1 T1 ROYER TX CN2
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VIN GND +5V ENABLE BRITE_IN
C1
C2
C3
Q1
Q2
LX1695 Circuit
+5V
VINS
Enable
Approximate
R1 510
DIM FREQ =
6300 R2
[Hz], R [K]
R2 24.9K 1% 1
D1 BAV70
DIM_FREQ ENA FLT_DLY BRITE_IN
OLSNS GND ROYER VDD
8
N.C.
Enable
2
7 R3 56K
+5V
C4 0.22F
R5 2.2M C5 1F
3
6
R4 470
VIN Royer Input Voltage (Buck Output) +5V 5VDC for LX1695 5V 5% 100mA ENABLE CIRCUIT On / Off Signal 5V Logic Level > 2.4V : On | <0.8V : Off
4
5
+5V
C6 1F
LX1695
VINS
Q4 BC847A
Q3 DTA114
R6 10K
BRITE_IN Burst Duty Control Voltage 0V ~ 2V = 3.125% ~ 100%
Q5 DTC144
D2 5.6V
Option: If system can not provide 5V, use this circuit.
Figure 2 - Typical Application
APPLICATIONS APPLICATIONS
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
THEORY OF OPERATION
WWW .Microsemi .C OM
DIGITAL DIMMING PWM A DC voltage to PWM converter provides an accurate digital dimming brightness control by varying Royer on time from 100% to as low as 3.125%. Minimum duty cycle is implemented by causing the Royer output signal to be high any time the DAC clock count is less than 8. Since the DAC is dual slope, this insures duty will be at least 16 out of the full 512 counts per cycle (See figure 3). The PWM includes an on chip oscillator that provides dimming burst rates between 30 and 600Hz. The oscillator frequency is trimmed to 3% accuracy (+20 to +65C) to prevent unwanted display artifacts that can be caused by the lamp dimming frequency beating with the displays video. Burst frequency can be controlled in two ways: An external resistor from DIM_FREQ to ground sets the frequency of the on chip oscillator. The formula for calculating a given ROYER output frequency based on the DIM_FREQ resistor to ground is as follows:
151.23E-9 As an example, if a ROYER output frequency of 120Hz is desired then: 151.23E-9 The closed nominal 1% resistor value would be 53.6K, nominally yielding a just slightly higher than 120Hz output. Dimming frequency becomes the oscillator frequency divided by 512 or a logic level pulse supplied through a 10K resistor to the DIM_FREQ pin overrides the internal timing circuits causing the dimming frequency to be input frequency divided by 512. The 10K external series resistor limits current into the ESD structure at the DIM_FREQ pin. The duty cycle at the Royer output is directly and linearly proportional to the DC level of signal BRITE_IN. Two (2.0) volts corresponds to 100% duty and zero volts corresponds to minimum duty. Minimum duty is internally limited to 3.125% even if BRITE_IN is zero volts High input impedance (>10 M) at the BRITE_IN pin makes it easy to set up minimum and maximum duty cycle outputs using only a few external resistors. The input pin is also directly compatible with Microsemi's LX1970 and 1971 ambient light sensors that provide automatic brightness control. R DIM_FREQ = R DIM_FREQ =
START-UP FAULT DELAY Open lamp detection is disabled for a programmable period after power turn-on, giving the Royer oscillators sufficient time to ignite all lamps. An external resistor and capacitor at pin FLT_DLY controls this time. The capacitor begins to charge at power on, and its exponential voltage rise is compared to a 2.1 volt reference to signal the end of fault delay interval. This condition is latched and then the external capacitor is discharged by an on chip NMOS transistor. Discharge time is about 10% of charge time, and the capacitor value can be up to 10uF. The resistor will typically be less than 1 megohm. OPEN LAMP DETECTION The open lamp detection circuit can sense if any lamp in the entire array is not conducting and shut the system off to prevent possible catastrophic system failure. Lamp current sensing is gated only during Royer on time and is delayed from its leading edge so that reliable detection is provided, even while dimming with very low duty cycles. Delay is 48 counts of the DAC clock beginning when Royer goes high. This gives the actual Royer oscillators time to come up to full power before testing for a broken lamp. At low dimming levels when the output duty cycle less than 12.5% open lamp sensing is internally disabled. This corresponds to about 0.25V on the BRITE_IN pin. An external R/C time out at pin FLT_DLY programs a delay after power-on to mask fault detection while the lamps are igniting. Typically this time-out is in the one to two second range, but can be as long as 5 seconds. Maximum recommended value of the resistor is 1 megohm to prevent error due to leakage current on the PCB, and low leakage ceramic capacitors are recommended. Typically this time-out is in the one to two second range, but can be as long as 5 seconds.
(1 ROYER Output Frequency -184.32E-6 )
(1 120 - 184.32E-6) = 53885
APPLICATIONS APPLICATIONS
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
OUTPUT FREQ VS RDIM FREQ
1000 Output Frequency (Hz) ROYER Duty Cycle (%) 100 90 80 70 60 50 40 30 20 10 0 1 10 100 RDIM_FREQ (k Ohms) 1000 0
ROYER DUTY CYCLE
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100
10
1
0 .2 0 .4 0 .6 0 .8
1
1 .2 1 .4 1 .6 1 .8
2
BRITE_IN (V)
ROYER VOL VS ISNK
1400 1200 1000 VOL (mV) 800 600 400 200 0 0 25 50 75 100 I SN K ( m A ) 125 150 175
85C V dd=4.5V N40C V dd=5.5V 25C V dd=5V
ROYER VOH VS ISNK
6 .0 5 .5 5 .0 VOH (mV) 4 .5 4 .0 3 .5 3 .0 2 .5 2 .0 0 25 50 75 100 I SN K ( m A ) 125 150 175
85C V dd=4.5V N40C V dd=5.5V 25C V dd=5V
DELAY TIME ENABLE
400 350
VALLEY VOLTAGE @ MIN DUTY +1%
50 45
Valley Voltage (mV)
Delay Time (ns)
40 35 30 25
300 250 200 150 -40 -20 0 20 40 60 80 100
Temperature (C)
CHARTS CHARTS
20 -40 -20 0 20 40 60 80 100
Temperature (C)
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
TIMING DIAGRAM
2V
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RAMP
0V
ROYER V BRITE_IN = 2.0V VBRITE_IN = 1.5V
5V (100% Duty) 0V 5V (75% Duty) 0V 5V (37.5% Duty) 0V 5V (3.125% Duty)
V BRITE_IN = 0.75V
V BRITE_IN < 0V
Figure 3 - Timing Diagram
0V
C CHARTS
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
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DM
8-Pin Plastic SOIC
A
P
Dim A B C D F G J K L M P *LC
B G C D KJ F L M
MILLIMETERS MIN MAX 4.83 5.00 3.81 3.94 1.35 1.75 0.33 0.51 0.77 1.27 BSC 0.19 0.25 0.13 0.25 4.80 5.21 8 5.79 6.20 0.10
INCHES MIN MAX 0.190 0.197 0.150 0.155 0.053 0.069 0.013 0.020 0.030 0.050 BSC 0.007 0.010 0.005 0.010 0.189 0.205 8 0.228 0.244 0.004
*Lead Coplanarity
M
8-Pin Plastic Mini Dip
MILLIMETERS MIN MAX 10.16 6.10 6.60 5.08 0.38 0.51 0.76 1.52 2.54 BSC 0.76 1.27 0.20 0.38 3.18 7.62 BSC 15 INCHES MIN MAX 0.400 0.240 0.260 0.200 0.0145 0.020 0.030 0.060 0.100 BSC 0.030 0.050 0.008 0.015 0.125 0.300 BSC 15
A
B 1
L
F
C
K H G D
J
Dim A B C D F G H J K L M
M
MECHANICALS MECHANICALS
*Lead Coplanarity
Note:
1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006") on any side. Lead dimension shall not include solder coverage.
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9
LX1695
TM (R)
Switched Royer CCFL Inverter Monitor IC
PRODUCTION DATA SHEET
NOTES
WWW .Microsemi .C OM
NOTES NOTES
PRODUCTION DATA - Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not necessarily include testing of all parameters. Microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time.
Copyright (c) 2004 Rev. 1.0a, 2006-01-06
Microsemi
Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 10

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