www.DataSheet4U.com OZ960 Intelligent CCFL Inverter Controller FEATURES • • • • • • • • • • • Supports wide-range voltage input applications (8v to 20v) Built-in intelligence to manage ignition and normal operation of CCFLs Reduces the number of components and board size by 30% compared with conventional designs 85% efficiency vs. typical 70% efficiency of conventional designs Zero-voltage-switching full bridge topology Built-in internal open-lamp and over-voltage protections Integrated burst mode control, and wide dimming range (10% to 100%) with integrated burst mode control Supports multiple CCFL lamps Simple and reliable 2-winding transformer design Constant-frequency design eliminates interference with LCDs Low stand-by power quality waveform received, at the CCFL voltage and current. The OZ960 operates at a single, constant frequency in a phase-shift PWM mode. Intelligent open-lamp and over-voltage protections provide design flexibility so various transformer models/manufacturers may be used. The built-in burst mode control provides a wide dimming range and simplifies the application circuit designs. Both operating and burst-mode frequencies are user-programmable parameters. The single stage design results in a low cost, reliable transformer without expensive, less reliable secondary fold-back treatment. The transformer does not require a more expensive center tapped primary. The OZ960 is available in a 20-pin SSOP package. It is specified over the commercial temperature range of 0°C to +70°C, and the industrial temperature range of -40°C to +85°C. ORDERING INFORMATION FUNCTIONAL BLOCK DIAGRAM OZ960S - 20-pin plastic SSOP 150mil OZ960IS - 20-pin plastic SSOP 150mil OZ960G - 20-pin plastic SOP 300mil OZ960IG - 20-pin plastic SOP 300mil OZ960D - 20-pin plastic DIP 300mil OZ960ID - 20-pin plastic DIP 300mil Refer to the functional block diagram in Figure 2, page 3, and the Pin Description Table on page 4. GENERAL DESCRIPTION The OZ960 is a unique, high-efficiency, Cold Cathode Fluorescent Lamp (CCFL) backlight inverter controller that is designed for wide input voltage inverter applications. Additionally, the OZ960 performs the lamp dimming function with an analog voltage or low frequency Pulse Width Modulation (PWM) control. Operating Principle: Operating in a zero-voltage switching, full-bridge configuration, the inverter circuit achieves a very high efficiency power conversion. In addition, the transformer in the OZ960 does not require any specific gap-less arrangement. The simple, low cost transformer provides designers a high degree of design flexibility in specifying transformers. Setting the switching frequency higher than the resonant frequency of a highquality-factor resonant tank circuit yields a good- 10/23/01 Copyright 2000 - 01 by O2Micro A precision reference provides a reference voltage for both internal and external uses. An oscillator circuit generates a user-programmable operating frequency with an external capacitor and a timing resistor. In addition, another resistor to program striking frequency is provided. The drive circuit consists of four outputs. These are designed to achieve zero-voltage switching, fullbridge applications. An error amplifier is provided to regulate the CCFL current. The Soft-start circuit offers a gradual increase of the power to the CCFL during the ignition period. The overvoltage protection block offers a regulated striking voltage for CCFLs. The striking time is programmable simply through an external component. The open-lamp protection is integrated in the protection block. This block intelligently differentiates the striking condition and open-lamp condition. ENA circuitry enables the operation of the IC through a TTL signal interface. Wide-dimming control is achieved through the burst-mode control block. OZ960-DS-1.6 All Rights Reserved Page 1 U.S. Patent #6,259,615 Vin VIN DIM 5VDC ENA GND J1 Figure 1: An 8-22V Application Circuit of OZ960 OZ960-DS-1.6 0.1u C13 0.47u C9 RT 0.015u C14 R5 240K 1.0u C2 VIN: 8.0V---22V ENA: 0V--1.0V Disable;2.0V---3.3V Enable DIM: 3V Max. Brightness; 1.2V Min. Brightness Striking frequency: 74KHz - 82KHz Operating frequency: 56KHz - 64KHz 1.0u C8 22 R1 10 9 8 7 6 5 4 3 2 1 51k R8 CMP FB RT1 REF GNDA VDDA SST ENA OVP CTIMR PDR_C LPWM DIM LCT PGND RT CT PDR_A NDR_B R6 33k NDR_D OZ960 U2 FUSE 1A F1 11 12 13 14 15 16 17 18 19 20 RT C10 6.8nF 220P C5 R3 1M R7 0.047u C12 4.7V 10K D2 C15 0.1u R2 5.1K 52.3K R4 0.047u C3 D1 4.7V 10U C1 4 3 2 1 4 3 2 1 U1 Si5504 U3 QC QD QA QB Si5504 5 6 7 8 5 6 7 8 32:2200 T1 2.2U C6 BAV99L CR2 2 1 J2 BAV99L CR1 R9 499 0.033U C11 22P C7 100P C4 www.DataSheet4U.com OZ960 TYPICAL APPLICATION CIRCUIT Page 2 www.DataSheet4U.com OZ960 I=3uA 1 2V CTIMR OVP + 2 20 NDR_B PDR_A 19 PDR_A 18 CT 17 RT 16 PGND 15 LCT 14 DIM 13 LPWM PDR_C 12 PDR_C NDR_D 11 NDR_D I=6uA OVP Protection - hys. COMP ENA NDR_B POFF Soft Start + 3 ENA 1.5V ACTIVE "HIGH" SST 4 VDDA 5 GNDA 6 REF 7 RT1 8 FB 9 - HF OSC hys. COMP POFF Reference 2.75V OPLAMP 2.50V + ZVS Phase-Shift Controller BurstMode Control Ignition EA + CMP 10 1.25V Figure 2. Functional Block Diagram OZ960-DS-1.6 Page 3 www.DataSheet4U.com OZ960 PIN DESCRIPTION Names Pin No. I/O CTIMR OVP ENA SST VDDA GNDA REF RT1 FB CMP NDR_D PDR_C LPWM DIM LCT PGND RT CT PDR_A NDR_B 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 I I I I I I O I I O O O O I I I I I O O Description Capacitor for CCFL ignition duration Output voltage sense Vth=2.0V Enable input; TTL signal is applicable Soft-start capacitor Voltage source for the IC Analog signal ground reference Reference voltage output; 2.5V typical Resistor for programming ignition frequency CCFL current feedback signal Compensation output of the current error amplifier NMOSFET drive output PMOSFET drive output Low-frequency PWM signal for burst-mode dimming control Input analog signal for burst-mode dimming control Triangular wave for burst-mode dimming; frequency Power ground reference Timing resistor set operating frequency Timing capacitor set operating frequency PMOSFET drive output NMOSFET drive output ABSOLUTE MAXIMUM RATINGS WITH RESPECT TO INPUT POWER SOURCE RETURN REFERENCE (1) VDDA 7.0V GNDA, PGND +/- 0.3V Logic inputs -0.3V to VDD +0.3V OZ960 Operating temp. o OZ960I o 0 C to 70 C o o Operating junction temp. Storage temp. o -40 C to 85 C 150 C o o -55 C to 150 C RECOMMENDED OPERATING RANGE VDDA 4.7V ~ 5.5V Fosc 30 KHz to 150 KHz Rosc 50 k to 150 k (1) Note : The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The “Functional Specifications” table will define the conditions for actual device operation. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. OZ960-DS-1.6 Page 4 www.DataSheet4U.com OZ960 FUNCTIONAL SPECIFICATIONS Parameter Symbol Test Conditions Limits o Unit VDDA=5V; Tamb = 25 C Min Typ Max Reference Voltage Nominal voltage Iload = 0.1mA 2.37 2.5 2.63 V Line regulation Vref VDDA = 4.7V – 5.3V - 4 - mV/V Load regulation Iload = 0.025 mA to 0.25 mA - 2 - mV/mA CT = 100pF, RT = 120k(1) 53 57 60 KHz - 3.0 - V High Frequency Oscillator Initial accuracy fosc Ramp peak Ramp valley - 1.0 - V - 200 - ppm/ oC Ramp peak 2.85 3.0 3.15 V Ramp valley 0.94 1.0 1.06 V 0 - 100 % Input offset voltage - 7 - mV Input voltage range 0 - VDD-1.5V V Offset current at FB pin - - 100 nA 1.19 1.25 1.31 V Open loop voltage gain - 80 - dB Unity gain bandwidth - 1.0 - MHz Power supply rejection - 60 - dB 1.90 2 2.15 V - 150 200 µA - 4.4 5.5 mA TA = 0 oC to 70oC Temp. stability Low Frequency Oscillator See Table 1, page 6 Initial accuracy Low Frequency PWM Duty Cycle Range Error Amplifier Reference voltage at noninverting input pin (internal) VADJ Threshold Over Voltage Protection Supply Supply current IOFF ENA = low ENA = high; VDDA = 5V; Supply current ION Vdim = 2V; LPWM = 50k(2) Ca=Cb=Cc=Cd=2nF(3) HF = 60kHz; LF = 185Hz SST current See Table 1, page 6 CTIMR current See Table 1, page 6 NDR-PDR Output Output resistance Rp Current source - 27 - Ω Output resistance Rn Current sink - 14 - Ω OZ960-DS-1.6 Page 5 www.DataSheet4U.com OZ960 Parameter Symbol Test Conditions Limits Unit Max. / Min. Overlap VDDA = 5V; Tamb = 25oC HF = 60kHz Min. Overlap between diagonal switches Ca=Cb=Cc=Cd=2nF(3) Max. Overlap between diagonal switches Ca=Cb=Cc=Cd=2nF(3) HF = 60kHz Min Typ Max 3.0 4.5 5.5 % 78 81 84 % Brake before Make PDR_A / NDR_B See Table 1, below PDR_C / NDR_D See Table 1, below OZ960 Parameter Symbol Test Conditions OZ960I Limits Unit Min Typ Max 160 220 250 ISST 4.9 7.5 ICTIMR 2.2 Limits Unit Min Typ Max Hz 150 220 340 Hz 10 µA 4.9 6.0 12 µA 3.3 4.5 µA 2.0 3.0 5.2 µA Low Frequency Oscillator Initial accuracy fosc LCT = 6.8nF, LPWM = 50k(2) Supply SST current CTIMR current Brake before Make PDR_A / NDR_B HF = 60kHz 250 380 530 ns 250 380 565 ns PDR_C / NDR_D HF = 60kHz 250 380 520 ns 250 380 545 ns 1.35 1.50 1.65 V 1.25 1.50 1.65 V Threshold Enable Table 1. Low Frequency Oscillator, Supply and Brake before Make Specifications for OZ960 and OZ960I Note (1) CT: capacitor from CT (Pin 18) to ground RT: resistor from RT (Pin 17) to ground Note (2) LCT: capacitor from LCT (Pin 15) to ground LPWM: resistor from LPWM (Pin 13) to ground Note (3) Ca: capacitor from PDR_A (Pin 19) to VDDA Cb: capacitor from NDR_B (Pin 20) to ground Cc: capacitor from PDR_C (Pin 12) to VDDA Cd: capacitor from NDR_D (Pin 11) to ground OZ960-DS-1.6 Page 6 www.DataSheet4U.com OZ960 FUNCTIONAL INFORMATION 1. Steady-State Operation Refer to the schematic shown in Figure 1, the OZ960 drives a full-bridge power train where the transformer couples the energy from the power source to the secondary CCFL load. The switches in the bridge denoted as QA, QB, QC and QD are configured such that QA and QB, QC and QD are turned on complementarily. The duration of QA and QD, QB and QC turn on simultaneously determines an amount of energy put into the transformer which in turn delivers to the CCFL. The current in CCFL is sensed via resistor R9 and regulated through the adjustment of the turn-on time for both diagonal switches. This is accomplished through an error amplifier in the current feedback loop. A voltage loop is also established to monitor the output voltage so that a programmable striking voltage is achieved. The OVP represents the peak-detect signal of the voltage on the output of the transformer. A softstart circuit ensures a gradual increase in the input and output power. The soft-start capacitor determines the rate of rise of the voltage on SST pin where the voltage level determines the ontime duration of QA and QD, QB and QC diagonal switches. This minimizes the surge impacts in circuit designs. Apply enable signal to the ENA pin of the IC after the bias voltage applied to VDDA initiates the operation of the circuit. The output drives, include PDR_A, NDR_B, PDR_C and NDR_D put out a complementary square pulse. The frequency is determined by R4 and C5 where they are connected to RT and CT pins respectively. Initially, the energy converted from the power source to the CCFL is low due to the soft start function. It increases as soft start capacitor voltage increases linearly with time. The voltage at the secondary side of the transformer T1 increases correspondingly. This process continues until the CCFL current is detected and reaches a regulated value. The output of the error amplifier, CMP, follows the feedback signal, commands a proper switching among the four output drives to maintain current regulation. The operations of the four switches are implemented with zero-voltage-switching to provide a highefficiency power conversion. regulated through a voltage feedback loop where output voltage is monitored. The signal, being sent to the OVP pin, commands the output drives to provide the desired output voltage. This design provides high degree of flexibility while maintaining OZ960 a very high integration device. One protection feature needed is removing the lamp during normal operation. The OZ960 senses the missing current signal through current amplifier, it shuts off the output drives and stay in the latched mode. This is differentiated intelligently with turning on the inverter while CCFL is not connected. Recycle of the IC power is necessary to resume normal operation. Dimming control: dimming control of the inverter is implemented by adjusting the amount of energy processed and delivered to the CCFL. A PWM burst-mode scheme is internally generated which provides 0% to 100% wide dimming control. An input analog voltage signal is fed into DIM pin and determines the dimming level of the CCFL. The burst-mode frequency is programmable through a capacitor C10 as shown in the schematic. The OZ960 inverter operates in a constant frequency mode. This eliminates any undesired interference between inverter and LCD panels where the interference is usually associated with variable-frequency designs. Symmetrical drive to the power transformer gives a very dynamic choice of selecting transformers. This vulnerable design offers flexibility to the system designers to choose transformer sources. There is no limitation to the gap-less transformer. 2. CCFL Ignition Time Ignition time for CCFLs varies with CCFL length, diameter, module package and temperature. The OZ960 provides a flexible design where a capacitor is connected to CTIMR pin to determine the necessary striking time. An approximate of the timing calculation is: T[second] = C[uF] In the case of open-lamp condition, the OZ960 provides a programmable striking-frequency intelligence to optimize the ignition scheme. This is implemented through resistor R5. Effectively, R5 is in parallel with R4 to yield a required striking frequency. In addition, the striking time is also programmable through the capacitor C8. Striking voltage, or the open-lamp voltage, is This capacitor remains reset at no charge if lamp is connected and at normal operation. OZ960-DS-1.6 Page 7 www.DataSheet4U.com OZ960 3. Protection Open-lamp protection in the ignition period is provided through both OVP and CTIMR to ensure a rated voltage is achieved and a required timing is satisfied. Removal of the CCFL during normal operation will trigger the current amplifier output and shuts off the inverter. This is a latch function. 4. OVP The OVP threshold is set at 2V nominal. When the output voltage reaches the threshold, it commands the PWM controller to maintain the driving level. This ensures that output gets sufficient striking voltage while operating the power transformer safely. striking voltage and frequency. This add-on feature could optimally accomplish the ignition process so that the CCFL life could be extended. When RT1 is used, it is connected in parallel with RT during the ignition period. 9. Burst-Mode Dimming Control The OZ960 integrates a burst-mode dimming function to perform a wide dimming control for the CCFLs. The burst-mode frequency is determined by a capacitor C10 connected to LCT pin. The frequency can be calculated approximately by: 1496 f[Hz] = CLCT[nF] 5. ENA Applying positive TTL logic to the ENA pin enables the operation of the IC. The threshold of the ENA is set at 1.5V. Apply logic low to the ENA pin will disable the operation of the inverter. Toggle this signal allows the on/off tests for the inverter. The Dim pin compares with the triangle wave in LCT and yields a proper pulse width to modulate the CCFL current. This pulse can also be monitored through LPWM pin. The peak and valley of the LCT signal is 3V and 1V respectively. 6. Soft-Start -- SST 10. Output Drives The soft-start function is provided with a capacitor connected to SST pin. The soft-start time is not related to the striking time for the CCFL. It simply provides a rate of rise for the pulse width where diagonal switches are turned on. Normally, a 0.47uF capacitor is connected. The four output drives are designed so that switches QA and QB, QC and QD never turn on simultaneously. These include two NMOS and two PMOS transistors. The configuration prevents any shoot-through issue associated with bridge-type power conversion applications. Adjusting the overlap conduction between QA and QD, QB and QC, the CCFL current regulation is achieved. This overlap is also adjusted while the voltage applied from the battery varies. At a specific CCFL current, the input power is maintained almost constant. 7. Error Amplifier The CCFL current is regulated through this error amplifier. It also provides an intelligence of differentiating open-lamp striking versus removing the lamp during normal operation. The non-inverting reference is at 1.25V nominal. 8. Operating frequency A resistor RT and a capacitor CT determine the operating frequency of OZ960. The frequency is calculated as: 68.5•104 f[kHz] = Ω] CT[pF]•RT[kΩ The OZ960 also provides an optional striking frequency as desired. CCFL in a LCD module possesses parasitic that may require different OZ960-DS-1.6 Page 8 www.DataSheet4U.com OZ960 PACKAGE INFORMATION (SSOP 150mil) D Detail A E1 h x 45 deg E 1 c ZD A A2 0.10MM C SEATING PLANE A1 B e NOTES: DIMENSION D DOES NOT INCLUDE MOLD PROTRUSIONS OR GATE BURRS MOLD PROTRUSIONS AND GATE BURRS SHALL NOT EXCEED 0.006 INCH PER SIDE DIM θ2 θ1 0.25MM Gauge Plane R1 R θ L Detail A A A1 A2 B c e D E E1 L h ZD R1 R θ θ1 θ2 JEDEC MILLIMETERS INCHES MIN NOM MAX MIN NOM MAX 1.35 1.63 1.75 0.053 0.064 0.069 0.10 0.15 0.25 0.004 0.006 0.010 1.50 0.059 0.20 0.30 0.008 0.012 0.18 0.25 0.007 0.010 0.635 BASIC 0.025 BASIC 8.56 8.66 8.74 0.337 0.341 0.344 5.79 5.99 6.20 0.228 0.236 0.244 3.81 3.91 3.99 0.150 0.154 0.157 0.41 0.635 1.27 0.016 0.025 0.050 0.25 0.50 0.010 0.020 1.4732 REF 0.058 REF 0.20 0.33 0.008 0.013 0.20 0.008 0° 8° 0° 8° 0° 0° 5° 10° 15° 5° 10° 15° MO-137 (AD) OZ960-DS-1.6 Page 9 www.DataSheet4U.com OZ960 PACKAGE INFORMATION (SOP 300mil) b 11 20 D e t a il X H E 1 10 e c A D Y A1 S E A T IN G P L A N E NOTES: 1 . R E F E R T O J E D E C S T D . M S -0 1 3 A C . 2 . D IM E N S IO N S " D " D O S E N O T IN C L U D E M O L D F L A S H , P R O T R U S IO N S O R G A T E B U R R S . M O L D F L A S H , P R O T R U S IO N S A N D G A T E B U R R S S H A L L N O T E X C E E D 0 .1 5 m m (6 m il) P E R S ID E . 3 . D IM E N S IO N S " E " D O S E N O T IN C L U D E IN T E R L E A D F L A S H O R P R O T U R S IO N S . IN T E R -L E A D F L A S H A N D P R O T R U S IO N S S H A L L N O T E X C E E D 0 .2 5 m m (1 0 m il) P E R S ID E . 4 . C O N T R O L L IN G D IM E N S IO N : M IL L IM E T E R h x 45 O θ L DETAIL "X" SYMBOL A A1 b c D E e H h L Y θ MM NOM MAX 2.54 2.64 0.20 0.30 0.406 0.48 0.254 0.31 12.80 13.00 7.50 7.60 1.27 BSC 10.00 10.31 10.65 0.25 0.66 0.75 0.51 0.76 1.02 0.075 0° 8° MIN 2.36 0.10 0.35 0.23 12.60 7.40 OZ960-DS-1.6 MIN 93 4 14 9 496 291 394 10 20 0° MIL NOM 100 8 16 10 504 295 50 BSC 406 26 30 MAX 104 12 19 12 512 299 419 30 40 3 8° Page 10 www.DataSheet4U.com OZ960 PACKAGE INFORMATION (DIP 300mil) A A2 eB SEATING PLANE L A1 H E E1 θ° D 0.018typ. 0.100typ. 0.060typ. SYMBOL A A1 A2 D E E1 L eB θ MIN 0.015 0.125 0.98 NOR 0.130 1.030 0.300 BSC 0.245 0.250 0.115 0.130 0.335 0.355 0° 7° MAX 0.210 0.135 1.060 0.255 0.150 0.375 15° NOTES: 1. JEDEC OUTLINE: MS-001 AD 2. “D”, “E” DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH 3. eB IS MEASURED AT THE LEAD TIPS WITH THE LEADS UNCONSTRAINED. 4. POINTED OR ROUNDED LEAD TIPS ARE PREFERRED TO EASE INSERTION. 5. DISTANCE BETWEEN LEADS INCLUDING DAM BAR PROTRUSIONS TO BE .005 INCH MINIMUM. 6. DATUM PLANE H COINCIDENT WITH THE BOTTOM OF LEAD, WHERE LEAD EXITS BODY. OZ960-DS-1.6 Page 11 www.DataSheet4U.com OZ960 IMPORTANT NOTICE No portion of O2Micro specifications/datasheets or any of its subparts may be reproduced in any form, or by any means, without prior written permission from O2Micro. O2Micro and its subsidiaries reserve the right to make changes to their datasheets and/or products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. O2Micro warrants performance of its products to the specifications applicable at the time of sale in accordance with O2Micro’s standard warranty. Testing and other quality control techniques are utilized to the extent O2Micro deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. Copyright © 2002, O2Micro International Limited OZ960-DS-1.6 Page 12