DS3992 Rev 0 9/06 Two-Channel, Push-Pull CCFL Controller General Description Features Two-Channel CCFL Controller for Backlighting The DS3992 is a low-cost, two-channel controller for LCD Panels for PC Monitors and LCD-TVs cold-cathode fluorescent lamps (CCFLs) that are used to backlight liquid crystal displays (LCDs). The DS3992 Minimal BOM Provides Low-Cost Inverter Solution can drive multiple CCFLs per channel, making it ideal Per-Channel Lamp Fault Monitoring for Lamp- for 4- and 6-lamp LCD PC monitor and TV applications. Open, Lamp Overcurrent, Failure to Strike, and Overvoltage Conditions The DS3992 uses a push-pull drive scheme to convert a Accurate (10%) On-Board Oscillator for Lamp DC voltage (5V to 24V) to the high voltage (300V to RMS Frequency (40kHz to 80kHz) 1400V ) AC waveform that is required to power the RMS CCFLs. The push-pull drive scheme uses a minimal Accurate (10%) On-Board Oscillator for DPWM Burst-Dimming Frequency (90Hz to 220Hz or number of external components, which reduces compo- 180Hz to 440Hz) nent and assembly cost and makes the printed circuit board (PC board) design easy to implement. The push- Device Supply Undervoltage Lockout pull drive scheme also provides an efficient DC-to-AC Inverter Supply Undervoltage Lockout conversion and produces near-sinusoidal waveforms. Burst-Dimming Soft-Start Minimizes Audible Transformer Noise Strike Frequency Boost Applications 100% to < 10% Dimming Range LCD PC Monitors 4.5V to 5.5V Single-Supply Operation LCD-TVs -40C to +85C Temperature Range 16-Pin SO Package (150 mils) Ordering Information DIMMING PART TEMP RANGE BRIGHT POLARITY PIN-PACKAGE FREQUENCY RANGE DS3992Z-09P+ -40C to +85C 90Hz to 220Hz Positive 16 SO-16 (150 mils) DS3992Z-09N+ -40C to +85C 90Hz to 220Hz Negative 16 SO-16 (150 mils) DS3992Z-18P+ -40C to +85C 180Hz to 440Hz Positive 16 SO-16 (150 mils) DS3992Z-18N+ -40C to +85C 180Hz to 440Hz Negative 16 SO-16 (150 mils) DS3992Z-09P+T&R -40C to +85C 90Hz to 220Hz Positive 16 SO-16 (150 mils) DS3992Z-09N+T&R -40C to +85C 90Hz to 220Hz Negative 16 SO-16 (150 mils) DS3992Z-18P+T&R -40C to +85C 180Hz to 440Hz Positive 16 SO-16 (150 mils) DS3992Z-18N+T&R -40C to +85C 180Hz to 440Hz Negative 16 SO-16 (150 mils) +Denotes lead-free package. Pin Configuration T&R denotes tape-and-reel package. TOP VIEW 1 LOSC 16 V CC 2 15 V POSC CC 3 14 OVD2 BRIGHT 13 Typical Operating Circuits appear at end of data sheet. SVM 4 LCM2 DS3992 GA1 5 12 GB2 6 GA2 GB1 11 LCM1 7 10 V CC OVD1 8 9 GND SO-150 Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Two-Channel, Push-Pull CCFL Controller ABSOLUTE MAXIMUM RATINGS Voltage on V Relative to Ground.......................-0.5V to +6.0V Operating Temperature Range ...........................-40C to +85C CC Voltage on Any Leads Other Storage Temperature Range .............................-55C to +125C Than V ..............0.5V to (V + 0.5V), not to exceed +6.0V Soldering Temperature...................See J-STD-020 Specification CC CC Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS (T = -40C to +85C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V (Note 1) 4.5 5.5 V CC V + CC SVM Voltage Range V -0.3 V SVM 0.3 V + CC BRIGHT Voltage Range V -0.3 V BRIGHT 0.3 V + CC LCM Voltage Range V (Note 2) -0.3 V LCM 0.3 V + CC OVD Voltage Range V (Note 2) -0.3 V OVD 0.3 Gate-Driver Output Charge Loading Q 20 nC G ELECTRICAL CHARACTERISTICS (V = +4.5V to +5.5V, T = -40C to +85C.) CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS G , G loaded with 600pF, 2 channels A B Supply Current I 816 mA CC active Low-Level Output Voltage (GA, GB) V I = 4mA 0.4 V OL OL V - CC High-Level Output Voltage (GA, GB) V I = -1mA V OH1 OH1 0.4 UVLO Threshold: V Rising V 4.3 V CC UVLOR UVLO Threshold: V Falling V 3.7 V CC UVLOF UVLO Hysteresis V 100 mV UVLOH SVM Falling-Edge Threshold V 1.9 2.0 2.1 V SVM SVM Hysteresis V 150 mV SVMH LCM and OVD DC Bias Voltage V 1.35 V DCB LCM and OVD Input Resistance R 50 k DCB Lamp-Off Threshold V (Note 3) 1.65 1.75 1.85 V LOT Lamp Over Current V (Note 3) 3.15 3.35 3.55 V LOC Lamp Regulation Threshold V (Note 3) 2.25 2.35 2.45 V LRT OVD Threshold V (Note 3) 2.25 2.35 2.45 V OVDT Lamp Frequency Range f 40 80 kHz LFS:OSC 2 DS3992