Design Files
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10 Channel LED Backlight Driver with Power Supply
The MC34844/A is a high efficiency, LED driver for use in backlighting LCD displays from 10" to 27". Operating from supplies of 7 V to 28 V, the MC34844/A is capable of driving more than 150 LEDs in 10 parallel strings. Current in the 10 strings is matched to within ±2%, and can be programmed via the I²C/SM-bus interface.
The MC34844/A also includes a Pulse Width Modulation(PWM) generator for LED dimming. The LEDs can be dimmed to one of 256 levels, programmed through the I²C/SM-bus interface. Therefore dimming ratios up to 65,000:1 (256:1 PWM, 256:1 Current DAC) can be supported. External PWM inputs may also be used. Multiple devices can have synchronized PWM frequencies for reduced picture noise. Audible noise is reduced through support of frequencies up to 27 kHz (100 Hz to 25 kHz range for 34844 and 110 Hz to 27 kHz for 34844A).
The MC34844/A also supports temperature and optical compensation loops, as well as ambient backlight control.
Product Details
Block Diagram
Features
Microcontrollers (MCUs)
- Input voltage of 7 V to 28 V
- Output voltage up to 60 V, with dynamic headroom control
- Output current 2.5 A
- Up to 50 mA LED current per channel (34844)
- Up to 80 mA LED current per channel (34844A)
- 90% efficiency (DC:DC)
- 10-channel current mirror with ±2% current matching
- I²C/SMbus interface
- 8-bit programmable current DAC
- User programmable OVP
- LED failure detection and OTP/OCP/UVLO lockout
- PWM frequency programmable or synchronizable from 100 to 25,000 Hz for the 34844
- PWM frequency programmable or synchronizable from 110 to 27,000 Hz for the 34844A
- 32-Ld 5x5x0.8mm TQFN Pb-Free Packaging
Key Features
- Parallel interface and input control
- I²C interface and input control
Buy/Parametrics
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Documentation
Quick reference to our documentation types.
1-5 of 6 documents
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Application Note
AN1902: Assembly Guidelines for QFN and SON Packages Application NoteFeatured
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Product Change Notice
Copper Wire and Case Outline Qualification (QFN)
Design Resources
Hardware
Quick reference to our
board types.
1 hardware offering
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Evaluation and Development BoardsEvaluation Kit - 34844, LED Backlight Driver, Power SupplyFeatured
Engineering Services
To get further assistance directly from NXP, please see our Engineering Services.
1 engineering service
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Original Design Manufacturer (ODM)
Hardware and Software Engineering Services
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