MAX8722C

19-3321; Rev 3; 2/09 KIT ATION EVALU E L B AVAILA Low-Cost CCFL Backlight Controller General Description Features o Synchronized to Resonant Frequency Longer Lamp Life Guaranteed Striking Capability High Power to Light Efficiency o Wide Input Voltage Range (4.6V to 28V) o Input-Voltage Feed-Forward for Excellent Line Rejection o Accurate Dimming Control with Analog Interface o 10:1 Dimming Range o Adjustable Accurate DPWM Frequency with Sync Function o Adjustable Lamp Current Rise and Fall Time o Secondary Voltage Limit Reduces Transformer Stress o Lamp-Out Protection with Adjustable Timeout o Secondary Overcurrent Protection with Adjustable Timeout o Low-Cost, 24-Pin QSOP Package MAX8722C The MAX8722C integrated backlight controller is optimized to drive cold-cathode fluorescent lamps (CCFLs) using a full-bridge resonant inverter architecture. Resonant operation maximizes striking capability and provides near-sinusoidal waveforms over the entire input range to improve CCFL lifetime. The controller operates over a wide input voltage range (4.6V to 28V) with high power to light efficiency. The device also includes safety features that effectively protect against many single-point fault conditions including lamp-out and short-circuit faults. The MAX8722C achieves 10:1 dimming range by “chopping” the lamp current on and off using a digital pulsewidth modulation (DPWM) method. The DPWM frequency can be accurately adjusted with a resistor or synchronized to an external signal....