ml4877 Microsemi Corporation, ml4877 Datasheet
ml4877
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ml4877 Summary of contents
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... GENERAL DESCRIPTION The ML4877 is an ideal solution for driving multiple cold cathode fluorescent tubes (CCFL) used in liquid crystal display (LCD) backlight applications. It provides dimming ballast control for the LCD display. By utilizing differential drive the ML4877 can deliver the same light output with significantly less input power compared to existing single ended drive schemes ...
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... Negative input for lamp error amplifier 8 LEA OUT Output of lamp error amplifier. External compensation capacitor connects between this pin and LEA Oscillator timing capacitor RTD Input to resonant threshold detector 2 ML4877 20-Pin SSOP (R20) LEA AZR CAP VREF ...
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... Current into L RTD ............................................... ±10mA Junction Temperature .............................................. 150ºC Storage Temperature Range ....................... -65ºC to 150ºC Lead Temperature (Soldering 10 sec.) ..................... 260ºC Thermal Resistance ( OPERATING CONDITIONS , VREF, T Temperature Range ML4877C ................................................... 0ºC to 70ºC ML4877E...............................................–20ºC to 70ºC = Operating Temperature Range CONDITIONS I = 5µA LOAD I = 25µ ...
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... ML4877 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER DELAY TIMER Delay Time HIGH VOLTAGE INVERTER Oscillator Nominal Frequency Discharge Current Peak Voltage Valley Voltage Output Drivers Output High - L GATE 1, 2 Output Low - L GATE 1, 2 Rise & Fall Time - L GATE 1, 2 Resonant Threshold Detector Threshold ...
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... Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions. Note 2: Actual load is 1200pF. The 2:1 transformer reflects an effective 2400pF. (Continued) CONDITIONS ON/OFF = “I”, no load ON/OFF = “0”, HVDD = 12V I = 25µA LOAD T = 25ºC A ML4877 MIN TYP MAX UNITS 375 450 µ µA 10 ...
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... VDD 2 13 HVDD LINEAR 12 REGULATOR VREF MASTER 5 BIAS & UVLO C3 1.0µF ON/OFF PGND GND Figure 1. Typical Application Schematic for the ML4877 6 U2 SYNC VDD DR3 DR1 DR1 ONE NEG SHOT EDGE DELAY ...
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... MOSFETs, Q3 and Q4. The lamp current, and therefore brightness, is adjusted by varying the voltage applied to R4, at the brightness adjust control point. Increasing this voltage increases the brightness. OSCILLATOR The frequency of the oscillator in the ML4877 is set by selecting the values OUT DRAIN-Q4 ...
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... PWM technique with no flicker and no pop- on effects. Uniform intensity can be maintained across lamps to well below 5%. Figure 6 provides a top view of an example of a ML4877 30W design. This design can be modified for lamps and contains a PWM dimming interface using standard low cost components ...
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... C T HVDD 11 C14 C12 L RTD B SYNC OUT 1µF 1µ U1A 6 – C11 4 1µF C15 1µF C10 0.033µF R10 10k ML4877 1kV 68pF 1kV 68pF 1kV 68pF ...
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... ML4877 Figure 6. 30W CCFL Inverter Board Lamps 10 ...
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... ORDERING INFORMATION PART NUMBER ML4877CR (END OF LIFE) ML4877ER (OBSOLETE) © Micro Linear 1998 registered trademark of Micro Linear Corporation. All other trademarks are the property of their respective owners. Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; ...