DIT8545 Ceratrans Driver for LCD Backlight DESCRIPTIONS DIT8545 is an advanced LCD backlight inverter control IC based on the piezo-ceramic transformer. The new control scheme employing the variable fr equency and duty control achieves the very high efficiency over 90%. In this control scheme, the soft start and zero voltage switching functions are aut omatically obtained. DIT8545 can realize the CCFL backlight inverter with small size and low cost. FEATURES ORDER INFORMATION - Soft start function - Programmable Operating Frequency - Analog Dimming Control Function - Burst Dimming Control - ON/OFF Control Function - Open Lamp Protection - 10SSOP Package Device Package Operating Temp DIT8545 10SSOP-225 -25 OC ~ +85 OC BLOCK DIAGRAM VCC CT 1 UVLO RT OUT CT 2 RT 10 VFVCO Driver 9 TONCT L EI GND 3 4 TONCTL 5 Aug. 2002 Error Amp EO 8 Bandgap Reference Bias Generator Latch ON/OFF 7 PROT 6 WWW.INTERPIONSEMI.COM -1- DIT8545 Ceratrans Driver for LCD Backlight PIN CONNECTIONS VCC 10 OUT GND ON/OFF PROT 9 8 7 6 DIT8545 1 2 3 4 CT RT EI EO 5 TONCTL PIN DESCRIPTIONS NO SYMBOL I/O 1 CT I TIMING CAPACITOR CONNECTION 2 RT I TIMING RESISTOR CONNECTION 3 EI I ERROR AMPLIFIER INPUT 4 EO O ERROR AMPLIFIER OUTPUT 5 TONCTL I SWITCH ON TIME CONTROL INPUT 6 PROT I OPEN LAMP PROTECTION INPUT 7 ON/OFF - ON/OFF CONTROL INPUT 8 GND I GROUND 9 OUT O OUTPUT 10 VCC - SUPPLY VOLTAGE INPUT Aug. 2002 DESCRIPTION WWW.INTERPIONSEMI.COM -2- DIT8545 Ceratrans Driver for LCD Backlight ABSOLUTE MAXIMUM RATINGS CHARACTERISTICS SYMBOL VALUE UNIT Supply Voltage Vcc 13.5 V Power Dissipation Pd 0.3 W Operating Temperature Topr -25 ~ +85 O Storage Temperature Tstg -55 ~ 150 O C C RECOMMENDED OPERATING CONDITIONS CHARACTERISTICS SYMBOL VALUE UNIT Supply Voltage Vcc 3~13.5 V Oscillator Frequency fosc 40~250 kHz ELECTRICAL CHARACTERISTICS (Ta = 25O C, VCC=5V, RT=13.8K CT=1.5V, PROT=0V unless otherwise specified.) CHARACTERISTICS SYMBOL CONDITIONS MIN TYP MAX UNIT [ Operating Current Specifications] On State Supply Current Icc(on) ON/OFF=2V - 3.5 6 mA Off State Supply Current Icc(off) ON/OFF=0V - 350 600 uA CT=470pF - 4 7 mA Average Operating Current Iop On State Start-up Current Ist(on) VCC=VthH - 0.3V ON/OFF=2V - 250 400 uA Off State Start-up Current Ist(off) VCC=VthH - 0.3V ON/OFF=0V - 200 400 uA 1.235 1.260 1.285 V - 7 16 mA [ Voltage Controlled Oscillator ] RT Voltage RT Terminal Maximum Current Vref IRTmax RT=0V RT Voltage Line Regulation Vline VCC=5V ->12V -20 2 20 mV RT Voltage Load Regulation Vload Io=100uA~1mA -20 2 20 mV Aug. 2002 WWW.INTERPIONSEMI.COM -3- DIT8545 Ceratrans Driver for LCD Backlight ELECTRICAL CHARACTERISTICS (Ta = 25O C, VCC=5V, RT=13.8K CT=1.5V, PROT=0V unless otherwise specified.) CHARACTERISTICS SYMBOL CONDITIONS MIN TYP MAX UNIT 120 135 150 kHz - 0.3 1.5 %/V Operating Frequency Fosc CT=470pF Frequency Change With Supply Voltage Dfosc VCC=5V to 12V Minimum Duty Ratio Dmin TONCTL = 0V 10 20 30 % Maximum Duty Ratio Dmax TONCTL = 3V 55 65 75 % Ib(TON) TONCTL = 0V - -0.1 -1 uA Upper Threshold Voltage VthH VCC Variation 2.6 2.8 2.95 V Lower Threshold Voltage VthL VCC Variation 2.4 2.6 2.8 V UVLO Hysteresis Voltage Vhys VCC Variation 0.1 0.2 0.4 V - 1 1.3 1.8 V ON/OFF=2V 5 20 50 uA -0.1 -1 uA TONCTL Input Bias Current [ UVLO Section ] [ ON/OFF Section ] ON/OFF Logic High Voltage Von/off ON/OFF Input Bias Current Ib(on/off) [ Error Amplifier Section] Erramp Input Bias Current Ib(EI) Inverting Reference Voltage Vfb 1.220 1.260 1.300 V Erramp Output Source Current Isource 3 10 30 mA Erramp Output Sink Current Isink 5 15 40 mA Erramp Output High Voltage Vhigh 3.2 4.2 4.5 V Erramp Output Low Voltage Vlow - 0.1 0.4 V [ Open Lamp Protection Section ] Protection Input Bias Current Iprot PROT=1.5V - 1 40 uA Protection Input Voltage Vprot - 1 1.35 1.60 V Aug. 2002 WWW.INTERPIONSEMI.COM -4- DIT8545 Ceratrans Driver for LCD Backlight ELECTRICAL CHARACTERISTICS (Ta = 25O C, VCC=5V, RT=13.8K, CT=1.5V, PROT=0V unless otherwise specified.) CHARACTERISTICS SYMBOL CONDITIONS MIN TYP MAX UNIT [ Output Driver Section ] Output High Voltage 1 Voh1 VCC = 3V, Io = 1uA 2.0 2.4 2.8 V Output High Voltage 2 Voh2 VCC = 5V, Io = 1uA 3.5 4.5 5.5 V Output High Voltage 3 Voh3 VCC = 8V, Io = 20mA 2.5 3.3 4.2 V Output Low Voltage 1 Vol1 VCC = 3V, Io = 100uA - 0.1 0.4 V Output Low Voltage 2 Vol2 VCC=5V, Io = 1mA - 0.2 0.4 V Output Voltage with UVLO Activated Vouv VCC=2V 0 0.2 0.4 V Output Source Current Output Sink Current Aug. 2002 Io(source) 20 mA Io(sink) 20 mA WWW.INTERPIONSEMI.COM -5- DIT8545 Ceratrans Driver for LCD Backlight TYPICAL APPLICATION Vin ON/OFF & BURST DIMMING B1 L1 CT1 C2 1 CT VCC 10 2 RT OUT 9 R1 3 EI R2 C4 R3 4 EO M1 GND 8 R11 C1 ON/OFF 7 R4 R5 RV1 CCFL C3 D8545 ANALOG DIMMING R10 R9 C7 D2 5 TONCTL PROT 6 R8 C5 GND R6 C6 D1 Aug. 2002 WWW.INTERPIONSEMI.COM R7 -6- DIT8545 Ceratrans Driver for LCD Backlight ELECTRICAL DIAGRAMS Duty(%) VTCTRL vs DUTY 70 CT=470p RT=13.8Kohm 60 50 40 30 20 10 0 0.0 0.5 1.0 1.5 2.0 VTCTRL(V) Fig.1 : VTCTRL vs. DUTY VTCTRL vs Frequency Frequency(kHz) 200 180 CT=470p RT=13.8Kohm 160 140 120 100 80 60 40 20 0 0.0 0.5 1.0 1.5 2.0 VTCTRL(V) Fig.2 : VTCTRL vs. Frequency Aug. 2002 WWW.INTERPIONSEMI.COM -7- DIT8545 Ceratrans Driver for LCD Backlight PACKAGE DIMENSION Aug. 2002 WWW.INTERPIONSEMI.COM -8-