DIT8545 INTERPION | Alldatasheet

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Technical content

Aug. 2002 - 1 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight DIT8545 is an advanced LCD backlight inverter con- trol IC based on the piezo-ceramic transformer. The new control scheme employing the variable fre- quency and duty control achieves the very high effi- ciency over 90%. In this control scheme, the soft start and zero voltage switching functions are aut o- matically obtained. DIT8545 can realize the CCFL backlight inverter with small size and low cost. - 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 -25OC ~ +85 OC DESCRIPTIONS BLOCK DIAGRAM ORDER INFORMATION

FEATURES

L RT CT VFVCO Driver

Aug. 2002 - 2 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight PIN DESCRIPTIONS NO SYMBOL I/O

DESCRIPTION

I TIMING CAPACITOR CONNECTION RT I TIMING RESISTOR CONNECTION EI I ERROR AMPLIFIER INPUT EO O ERROR AMPLIFIER OUTPUT TONCTL I SWITCH ON TIME CONTROL INPUT PROT I OPEN LAMP PROTECTION INPUT ON/OFF ON/OFF CONTROL INPUT GND I GROUND OUT O OUTPUT VCC SUPPLY VOLTAGE INPUT PIN CONNECTIONS OUT GND PROT CT RT EI EO TONCTL VCC ON/OFF DIT8545

Aug. 2002 - 3 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight CHARACTERISTICS SYMBOL VALUE UNIT Supply Voltage Vcc 13.5 V Power Dissipation Pd 0.3 W Operating Temperature Topr -25 ~ +85 OC Storage Temperature Tstg -55 ~ 150 OC ABSOLUTE MAXIMUM RATINGS CHARACTERISTICS SYMBOL VALUE UNIT Supply Voltage Vcc 3~13.5 V Oscillator Frequency fosc 40~250 kHz RECOMMENDED OPERATING CONDITIONS

ELECTRICAL CHARACTERISTICS

[ Operating Current Specifications] On State Supply Current Icc(on) ON/OFF=2V 3.5 mA Off State Supply Current Icc(off) ON/OFF=0V 350 600 uA Average Operating Current Iop CT=470pF mA 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 [ Voltage Controlled Oscillator ] RT Voltage Vref 1.235 1.260 1.285 V RT Voltage Line Regulation Vline VCC=5V->12V -20 mV RT Voltage Load Regulation Vload Io=100uA~1mA -20 mV RT Terminal Maximum Current IRTmax RT=0V mA (Ta = 25OC, VCC=5V, RT=13.8K CT=1.5V, PROT=0V unless otherwise specified.)

Aug. 2002 - 4 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight CHARACTERISTICS SYMBOL CONDITIONS MIN TYP MAX UNIT Operating Frequency Fosc CT=470pF 120 135 150 kHz Frequency Change With Supply Voltage Dfosc VCC=5V to 12V 0.3 1.5 %/V Minimum Duty Ratio Dmin TONCTL = 0V Maximum Duty Ratio Dmax TONCTL = 3V TONCTL Input Bias Current Ib(TON) TONCTL = 0V -0.1 uA [ UVLO Section ] 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 [ ON/OFF Section ] ON/OFF Logic High Voltage Von/off 1.3 1.8 V ON/OFF Input Bias Current Ib(on/off) ON/OFF=2V uA [ Error Amplifier Section] Erramp Input Bias Current Ib(EI) -0.1 uA Inverting Reference Voltage Vfb 1.220 1.260 1.300 V Erramp Output Source Cur- rent Isource mA Erramp Output Sink Current Isink 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 Cur- rent Iprot PROT=1.5V uA Protection Input Voltage Vprot 1.35 1.60 V (Ta = 25OC, VCC=5V, RT=13.8K CT=1.5V, PROT=0V unless otherwise specified.)

Aug. 2002 - 5 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight 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 0.2 0.4 V Output Source Current Io(source) mA Output Sink Current Io(sink) mA (Ta = 25OC, VCC=5V, RT=13.8K, CT=1.5V, PROT=0V unless otherwise specified.)

Aug. 2002 - 6 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight TYPICAL APPLICATION VCC OUT GND ON/OFF PROT TONCTL EO EI RT CT D8545 ANALOG DIMMING ON/OFF & BURST DIMMING Vin GND CT1 CCFL RV1 R10 R11

Aug. 2002 - 7 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight ELECTRICAL DIAGRAMS 0.0 0.5 1.0 1.5 2.0 CT=470p RT=13.8Kohm Duty(%) VTCTRL vs DUTY VTCTRL(V) 0.0 0.5 1.0 1.5 2.0 100 120 140 160 180 200 CT=470p RT=13.8Kohm VTCTRL vs Frequency VTCTRL(V) Frequency(kHz) Fig.1 : VTCTRL vs. DUTY Fig.2 : VTCTRL vs. Frequency

Aug. 2002 - 8 - WWW.INTERPIONSEMI.COM Ceratrans Driver for LCD Backlight PACKAGE DIMENSION