MAX8722

19-3321; Rev 0; 6/04 KIT ATION EVALU E L B A IL AVA Low-Cost CCFL Backlight Controller General Description Features ♦ Synchronized to Resonant Frequency Longer Lamp Life Guaranteed Striking Capability High Power to Light Efficiency ♦ Wide Input Voltage Range (4.6V to 28V) ♦ Input-Voltage Feed-Forward for Excellent Line Rejection ♦ Accurate Dimming Control with Analog Interface ♦ 10:1 Dimming Range ♦ Adjustable Accurate DPWM Frequency with Sync Function ♦ Adjustable Lamp Current Rise and Fall Time ♦ Secondary Voltage Limit Reduces Transformer Stress ♦ Lamp-Out Protection with Adjustable Timeout ♦ Secondary Overcurrent Protection with Adjustable Timeout ♦ Low-Cost 24-Pin QSOP Package MAX8722 The MAX8722 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 MAX8722 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. T...