LT1182 LINER [Linear Technology], LT1182 Datasheet
LT1182
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LT1182 Summary of contents
Page 1
... TYPICAL APPLICATION 90% Efficient Floating CCFL Configuration with Dual Polarity LCD Contrast ALUMINUM ELECTROLYTIC IS RECOMMENDED FOR C3B WITH AN ESR 0.5 TO PREVENT DAMAGE TO THE LT1182 HIGH-SIDE SENSE RESISTOR DUE TO SURGE CURRENTS AT TURN-ON. C1 MUST BE A LOW LOSS CAPACITOR WIMA MKP-20 Q1 ZETEX ZTX849 OR ROHM 2SC5001 ...
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... A for standby operation. A 200kHz switching frequency minimizes the size of required mag- netic components. The use of current mode switching techniques with cycle-by-cycle limiting gives high reliabil- ity and simple loop frequency compensation. The LT1182/ LT1183/LT1184/LT1184F are all available in 16-pin nar- row SO packages. U RATINGS LT1183/LT1184/1184F: REF Pin Source Current ...
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... Q I CCFL Switch On-Time SW1 V Reference Voltage REF Reference Output Impedance LT1182/LT1183/LT1184/LT1184F = SHUTDOWN = CCFL V = Open, DIO = GND, CCFL V CCFL SW = Open, (LT1182) FBN = FBP = GND, (LT1183 GND, CONDITIONS LT1182/LT1183 30V IN LT1184/LT1184F 30V IN SHUTDOWN = 0V, CCFL V = LCD V = Open (Note SHUTDOWN = 0V, CCFL V ...
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... P according to the following formula: D LT1182CS/LT1183CS/LT1184CS/LT1184FCS SHUTDOWN = CCFL V = Open, DIO = GND, CCFL V CCFL SW = Open, (LT1182) FBN = FBP = GND, (LT1183 GND, CONDITIONS Measured on LT1183 Measured on LT1184/LT1184F LT1182: Measured at FBP Pin, FBN = 1V, LCD V LT1183: Measured at FB Pin, LCD 30V, LCD ...
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... W U TYPICAL PERFORMANCE CHARACTERISTICS LT1182/LT1183 Supply Current vs Temperature 30V –75 – 50 – 100 125 150 175 TEMPERATURE ( C) LT1182 G01 Shutdown Input Bias Current vs Temperature 30V – ...
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... TEMPERATURE ( C) LT1182 • G14 CCFL V High Clamp Voltage C vs Temperature 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 150 175 –75 – 100 – TEMPERATURE ( C) LT1182 • G17 125 150 175 LT1182 • G12 125 150 175 LT1182 • G15 125 150 175 LT1182 • G18 ...
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... I = 100 A CCFL 7.1 7.0 6 CCFL 6.8 6.7 6 CCFL 6.5 –75 – 50 – 100 125 150 175 TEMPERATURE ( C) LT1182 • G26 LCD V High Clamp Voltage C vs Temperature 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 150 175 –75 – 50 – 100 125 TEMPERATURE ( C) LT1182 • G21 CCFL High-Side Sense Null Current Line Regulation vs Temperature 0 ...
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... LT1182 • G35 FBP Input Bias Current vs Temperature 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 –75 – 50 – 100 125 150 175 TEMPERATURE ( C) LT1182 • G30 FBP to LCD V Transconductance C vs Temperature 1300 1200 1100 1000 900 800 700 600 500 –75 – 50 – 100 ...
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... SW vs Duty Cycle 2 125 C MINIMUM 1.0 0 DUTY CYCLE (%) LT1182 • G38 Forced Beta LCD 100 1.8 2.0 0 0.2 0.4 0.6 0.8 1.0 1.2 LCD I (A) SW LT1182 • G41 LT1182 • G39 SW 1.4 1.6 1.8 2.0 LT1182 • G42 9 ...
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... I summing voltage in the LT1182/ CCFL LT1183/LT1184/LT1184F also a sense terminal for the LCD dual input error amplifier in the LT1182/LT1183. Connect external feedback divider networks that terminate to ground and frequency compensation components that terminate to ground directly to this pin for best regulation and performance ...
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... Royer and BAT pins together. This pin is only available on the LT1182/LT1183/ LT1184F. V (Pin 12): This pin is the supply pin for the LT1182/ IN LT1183/LT1184/LT1184F. The ICs accept an input voltage range of 3V minimum to 30V maximum with little change in quiescent current (zero switch current). An internal, low dropout regulator provides a 2 ...
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... In comparison to the LT1182, the FBN and the FBP pins tie together and come out as one pin. This scheme permits one polarity of contrast to be regulated. ...
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... W BLOCK DIAGRAM LT1182/LT1183 CCFL/LCD Contrast Regulator Top Level Block Diagram SHUTDOWN 6 SHUTDOWN LCD DRIVE 2 LOGIC 2 ANTI- SAT2 COMP2 + I R2 LIM AMP2 0.25 – GAIN = 4 100 A + LCD + + – – – 1.24V –12mV 0.45V – LCD LCD FBP ...
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... LT1182/LT1183/LT1184/LT1184F W BLOCK DIAGRAM LT1184/LT1184F CCFL Regulator Top Level Block Diagram SHUTDOWN 6 SHUTDOWN + CCFL 100 A – V REF V1 1.24V 0.465V 11 2 REF I CCFL LT1184/LT1184F: REFERENCE IS BROUGHT OUT TO PIN 1. PINS ARE NO CONNECT APPLICATIONS INFORMATION Introduction Current generation portable computers and instruments use backlit Liquid Crystal Displays (LCDs) ...
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... ON at the start of each oscillator cycle. The switches turn OFF when switch current reaches a predetermined level. The operation of the CCFL regulator in the LT1184/LT1184F is identical to that in the LT1182/ LT1183. The control of output lamp current is obtained by using the output of a unique programming block to set current trip level ...
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... This minimizes driver dissipation and provides rapid turn- off of the switch. The CCFL power switch is guaranteed to provide a minimum of 1.25A in the LT1182/LT1183/ LT1184/LT1184F and the LCD power switch is guaranteed to provide a minimum of 0.625A in the LT1182/LT1183. The anti-sat circuitry provides a ratio of switch current to driver current of about 50:1. Simplified Lamp Current Programming ...
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... The internal 0.1 high-side sense resistor on the LT1182/ LT1183/LT1184F is rated for a maximum DC current of 1A. However, this resistor can be damaged by extremely high surge currents at start-up. The Royer converter typically uses a few microfarads of bypass capacitance at the center tap of the transformer ...
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... Open-lamp conditions force the Royer converter to operate open-loop. Component stress is again worst-case with maximum input voltage conditions. The LT1182/LT1183/LT1184/LT1184F open-lamp pro- tection clamps the maximum transformer secondary volt- age to safe levels and transfers the regulator loop from current mode operation into voltage mode operation. ...
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... Com- promise is often the only remaining choice. LCD Contrast Circuits The LCD contrast switching regulator on the LT1182/ LT1183 operates in many standard switching configura- tions and is used as a classic DC/DC converter. The dual- input-stage error amplifier easily regulates either positive or negative contrast voltages ...
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... LT1182/LT1183/LT1184/LT1184F U TYPICAL APPLICATIONS 90% Efficient Grounded CCFL Configuration with Negative Polarity LCD Contrast C1 MUST BE A LOW LOSS CAPACITOR WIMA MKP-20 Q1 ZETEX ZTX849 OR ROHM 2SC5001 L1 = COILTRONICS CTX210605 L2 = COILTRONICS CTX100 COILTRONICS CTX02-12403 *DO NOT SUBSTITUTE COMPONENTS COILTRONICS (407) 241-7876 THE I CURRENT REQUIRED FOR AN CCFL RMS BULB CURRENT IS: – ...
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... Q1 ZETEX ZTX849 OR ROHM 2SC5001 L1 = COILTRONICS CTX210605 L2 = COILTRONICS CTX100-4 *DO NOT SUBSTITUTE COMPONENTS COILTRONICS (407) 241-7876 CURRENT GIVES CCFL 0mA TO 6mA LAMP CURRENT FOR A TYPICAL DISPLAY. D5 BAT85 C7 SHUTDOWN LT1182/LT1183/LT1184/LT1184F 6mA LAMP C2 27pF 3kV C3B 2 ...
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... LT1182/LT1183/LT1184/LT1184F U TYPICAL APPLICATIONS LT1182/LT1183 I PWM Programming CCFL V (PWM 40.5k 40.5k 1kHz PWM AND R2 ARE IDEAL VALUES. 2.2 F USE NEAREST 1% VALUE. LT1184/LT1184F I PWM Programming CCFL (PWM) 40.35k 40.35k 1kHz PWM AND R2 ARE IDEAL VALUES. ...
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... U TYPICAL APPLICATIONS 1 CCFL PGND 2 I CCFL 3 DIO 4 CCFL V 5 AGND 6 C8 SHDN R7 0.068 F 33K 7 LCD V 8 LCD PGND LT1182 LCD Contrast Positive Boost/Charge Pump Converter 1 CCFL PGND 2 I CCFL 3 DIO LT1182 4 CCFL AGND 6 C8 SHDN R7 0.068 F 33K 7 LCD LCD PGND Information furnished by Linear Technology Corporation is believed to be accurate and reliable ...
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... LT1182/LT1183/LT1184/LT1184F U TYPICAL APPLICATIONS LT1182 LCD Contrast Positive to Negative/Charge Pump Converter 1 CCFL CCFL V PGND 2 I CCFL 3 DIO LT1182 4 CCFL AGND 6 C8 SHDN R7 0.068 F 33K 7 LCD LCD LCD V PGND RELATED PARTS PART NUMBER FREQUENCY SWITCH CURRENT LT1107 63kHz 1A Hysteretic LT1172 100kHz 1 ...