LX1695 Switched Royer CCFL Inverter Monitor IC ® TM P RODUCTION D ATA S HEET KEY FEATURES DESCRIPTION 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 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. 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 Open Lamp Detection Input Gated for Royer High ENABLE Logic High Enable Royer Inverter GND ENABLE LX1695 FLT_DLY ROYER BRITE_IN VDD Royer Bias Drive 30 to 600 Hertz BRITE_IN Duty Cycle Control 0 to 2V = 3% to 100% VDD Fixed Input Supply 4.5 to 5.5V Programmable lamp strike interval at power on or enable LX1695 PACKAGE ORDER INFO TJ (°C) -40 to 85 M Plastic DIP 8-Pin DM Plastic SOIC 8-Pin RoHS / Pb-free 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 © 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 Switched Royer CCFL Inverter Monitor IC P RODUCTION D ATA S HEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT RoHS / Pb-free Peak Package Solder Reflow Temperature (40 seconds Maximum Exposure) .....................................................................................260°C (+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. THERMAL DATA M Plastic 8-Pin DIP THERMAL RESISTANCE-JUNCTION AMBIENT, θJA DM 85°C/W DIM_FREQ 1 8 OLSNS ENABLE 2 7 GND FLT_DLY 3 6 ROYER BRITE_IN 4 5 VDD DM Package (Top View) DIM_FREQ 1 8 OLSNS ENABLE 2 7 GND FLT_DLY 3 6 ROYER 4 5 VDD BRITE_IN WWW . Microsemi .C OM Supply Voltage (VDD) ........................................................................................6V Inputs (BRITE_IN, OLSNS, FLT_DLY, ENABLE, DIM_FREQ)................. VDD Output Current (ROYER) ...........................................................................150mA M Package (Top View) Plastic 8-Pin SOIC THERMAL RESISTANCE-JUNCTION AMBIENT, θJA 163°C/W RoHS / Pb-free 100% Matte Tin Lead Finish 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. FUNCTIONAL PIN DESCRIPTION Name Description VDD Input Voltage. The IC will be functional and in specifications when this pin is between 4.5 and 5.5VDC. GND 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. OL_SNS 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 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. FLT_DLY 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 DIM_FREQ ENABLE 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. Copyright © 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 PACKAGE DATA BRITE_IN LX1695 ® TM Switched Royer CCFL Inverter Monitor IC P RODUCTION D ATA S HEET Parameter Min Supply Voltage (VDD ) BRITE Linear DC Voltage Range DIM_FREQ, ENABLE, FLT_DLY Royer Output Frequency Range LX1695 Typ 4.5 0 0 30 Units Max 5.5 1.95 VDD 600 250 WWW . Microsemi .C OM RECOMMENDED OPERATING CONDITIONS V V V Hz 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 LX1695 Typ VDD=5.5V VDD=5.5V; Enable ≤ 0.4V VDD=5V; ENABLE = 5V VDD=5V; ENABLE = 0V VDD Rising -1 -1 3.7 0.01 -0.01 4 350 ISK_ROYER ISRC_ROYER TR TF BRITE_IN = 2V ROYER = 0.4V BRITE_IN = 2V ROYER = VDD-0.5V COUT = 1000pF COUT = 1000pF 40 75 100 20 20 Max 4.0 3.5 2 0.8 1 1 4.3 Units mA mA V V µA µA V mV 100 100 mA mA nS nS VDIM_FREQ ISCDIM_FREQ FROYER LOW DIM_FREQ = 0V; self limiting RDIM_FREQ = 215K 27 1 -600 30 33 V µA Hz FROYER NOM RDIM_FREQ = 25.2K 237 250 263 Hz FROYER HIGH IIHDIM_FREQ IILDIM_FREQ RDIM_FREQ = 10K DIM_FREQ = 3V; No RDIM_FREQ DIM_FREQ = 0.4V; No RDIM_FREQ 555 600 120 -475 645 Hz µA µA DIM_FREQ DIM_FREQ = 15KHz to 300KHz Square Wave 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 Hz 512 -1 -1 2.5 95 2.92 0.01 -0.01 3.125 52 100 40 1.9 1 1 5 µA µA % % % mV V 3 48 2.1 3.05 ‘V cycles V Note 1 : If duty cycle is set to less than 10% open lamp sensing is internally disabled Copyright © 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 ELECTRICALS ` Min IDD I_OUT OFF VIH VIL_ IIH_ENABLE IIL_ENABLE UV TH EXT CLK ROYER Output Frequency FROYER EXT_CLK ` Test Conditions LX1695 ® TM Switched Royer CCFL Inverter Monitor IC P RODUCTION D ATA S HEET ENABLE Enable 3V 1V 2.1V Bias Generator PwrBad UVLO WWW . Microsemi .C OM SIMPLIFIED BLOCK DIAGRAM Enable Fault Latch PwrBad R NoFault Q S Ignore_OLSNS PWM OLSNS 48 Count Ignore fault Logic 3V PwrBad 2V 9 Bit Dual Ramp DAC Clock Clock 0V PWM BRITE_IN 3.125% Min Duty Cycle VDD PwrBad FAULT_ DLY NoFault Power Buffer Ignore_OLSNS 2.1V ROYER Enable PwrBad Enable 1V DIM_FREQ A MUX OUT B SEL BLOCK DIAGRAM Internal Clock Generator Clock External Clock Detector Figure 1 – Simplified Block Diagram Copyright © 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 Switched Royer CCFL Inverter Monitor IC ® TM P RODUCTION D ATA S HEET L1 T1 ROYER TX F1 CN2 CN1 VIN C1 C2 GND +5V C3 ENABLE BRITE_IN Q1 Q2 LX1695 Circuit DIM FREQ = 6300 R2 [Hz], R [KΩ] R2 24.9K 1% Enable 1 2 +5V R5 2.2M 3 C5 1µF VINS Enable Approximate +5V 4 WWW . Microsemi .C OM APPLICATION CIRCUIT R1 510 D1 BAV70 DIM_FREQ OLSNS GND ENA FLT_DLY ROYER BRITE_IN VDD N.C. 8 7 R3 56K 6 5 C4 0.22µF +5V C6 1µF LX1695 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 VINS Q3 DTA114 R6 10K Q5 DTC144 Q4 BC847A BRITE_IN Burst Duty Control Voltage 0V ~ 2V = 3.125% ~ 100% D2 5.6V Option: If system can not provide 5V, use this circuit. Figure 2 – Typical Application APPLICATIONS Copyright © 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 Switched Royer CCFL Inverter Monitor IC P RODUCTION D ATA S HEET 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 +65°C) 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: R DIM_FREQ = (1 ROYER Output Frequency -184.32E-6 ) 151.23E-9 As an example, if a ROYER output frequency of 120Hz is desired then: R DIM_FREQ = (1 120 - 184.32E-6) = 53885 Copyright © 2004 Rev. 1.0a, 2006-01-06 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. Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 APPLICATIONS 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 MΩ) 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. 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. WWW . Microsemi .C OM THEORY OF OPERATION Page 6 LX1695 ® TM Switched Royer CCFL Inverter Monitor IC P RODUCTION D ATA S HEET ROYER DUTY CYCLE WWW . Microsemi .C OM OUTPUT FREQ VS RDIM FREQ 100 1000 ROYER Duty Cycle (%) Output Frequency (Hz) 90 100 10 80 70 60 50 40 30 20 10 0 1 1 10 100 RDIM_FREQ (k Ohms) 0 1000 N40°C V dd=5.5V 5 .5 25°C V dd=5V 5 .0 800 600 400 4 .5 4 .0 3 .5 85°C V dd=4.5V 3 .0 N40°C V dd=5.5V 200 2 .5 0 2 .0 0 25 50 75 100 I SN K ( m A ) 125 150 25°C V dd=5V 0 175 DELAY TIME ENABLE 25 50 75 100 I SN K ( m A ) 125 150 175 VALLEY VOLTAGE @ MIN DUTY +1% 400 50 350 45 Valley Voltage (mV) Delay Time (ns) 2 6 .0 VOH (mV) VOL (mV) 1000 1 .2 1 .4 1 .6 1 .8 ROYER VOH VS ISNK 85°C V dd=4.5V 1200 1 BRITE_IN (V) ROYER VOL VS ISNK 1400 0 .2 0 .4 0 .6 0 .8 300 250 200 40 35 30 25 CHARTS 150 20 -40 -20 0 20 40 60 80 100 Temperature (°C) Copyright © 2004 Rev. 1.0a, 2006-01-06 -40 -20 0 20 40 60 80 100 Temperature (°C) Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 LX1695 Switched Royer CCFL Inverter Monitor IC ® TM P RODUCTION D ATA S HEET WWW . Microsemi .C OM TIMING DIAGRAM 2V RAMP 0V 5V (100% Duty) ROYER V BRITE_IN = 2.0V 0V 5V (75% Duty) VBRITE_IN = 1.5V 0V 5V (37.5% Duty) V BRITE_IN = 0.75V 0V 5V (3.125% Duty) V BRITE_IN < 0V 0V Figure 3 – Timing Diagram CHARTS Copyright © 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 Switched Royer CCFL Inverter Monitor IC ® TM P RODUCTION D ATA S HEET DM WWW . Microsemi .C OM PACKAGE DIMENSIONS 8-Pin Plastic SOIC A Dim A B C D F P G B G L M C D K J F J K L M P *LC 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 A B 1 L C F K H G J M 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° MECHANICALS Dim A B C D F G H J K L M *Lead Coplanarity D 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 © 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 ® Switched Royer CCFL Inverter Monitor IC P RODUCTION D ATA S HEET 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 © 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