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Digitally Controlled CCFL Backlight Power Supplies

SMBus™ Controlled CCFL Supply Provides Bright, Flicker-Free Operation and Protects Lamps

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • Direct Digital Control of CCFL Brightness
  • Low Supply Current:
    • 3mA Max Operating
    • 20µA Max Shutdown
  • Low-Voltage Operation, Down to 4.5V
  • Internal 26V, 0.7Ω Power Switch
  • Protection Against Open or Shorted Lamps
  • Supports Isolated Transformer Secondary Winding
  • SMBus Serial Interface (MAX1611)
  • No Flicker at Low Brightness (internal 280Hz current chopping)
  • High Power-to-Light Efficiency
  • Selectable 290kHz/145kHz Switching Frequency
  • Oscillator SYNC Input
  • 16-Pin Narrow SO Package

Applications/Uses

  • Instrument Displays
  • Notebook Computers
  • Point-of-Sale Terminals
  • Portable Medical Equipment

Description

The MAX1610/MAX1611 are fully integrated, high-efficiency drivers for cold-cathode fluorescent lamps (CCFLs). They operate from a 4.5V to 26V power source. An on-board, high-switching-frequency power MOSFET reduces external component count and magnetics size. The MAX1610/MAX1611 protect against open or shorted lamps. The CCFL can be driven from an isolated transformer secondary winding to improve efficiency and avoid flicker at dim tube settings. Brightness is adjusted by scaling the lamp current, or by operating with a fixed lamp current and chopping the CCFL on and off at a rate faster than the eye can detect.

The MAX1610's digital inputs increment, decrement, or clear an internal, 5-bit up/down counter, which sets CCFL brightness. The MAX1611 uses a System Management Bus (SMBus) 2-wire serial interface to directly set CCFL brightness. Both devices include micropower shutdown and a linear regulator that eliminates the need for a separate logic supply. The digital interface remains active in shutdown, preserving the brightness setting.

Simplified Block Diagram

MAX1610, MAX1611: Pin Configuration MAX1610, MAX1611: Pin Configuration Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .