The MAX1895/MAX1995 integrated controllers are optimized to drive cold-cathode fluorescent lamps (CCFL) using a synchronized full-bridge inverter architecture. Synchronized drive provides near sinusoidal waveforms over the entire input range to maximize the life of CCFLs. The controllers also operate over a wide input voltage range with high efficiency and broad dimming range.
The MAX1895/MAX1995 include safety features that limit the transformer secondary voltage and protect against single-point fault conditions including lamp-out and short-circuit faults.
The MAX1895/MAX1995 regulate the CCFL brightness in three ways: linearly controlling the lamp current, digital pulse-width modulating (DPWM) the lamp current, or using both methods simultaneously to achieve the widest dimming range (>30:1). CCFL brightness can be controlled with either an analog voltage (both MAX1895 and MAX1995) or a two-wire SMBus™ compatible interface (MAX1895 only).
The MAX1895/MAX1995 directly drive the four external N-channel power MOSFETs of the full-bridge inverter. An internal 5.3V linear regulator powers the MOSFET drivers, the synchronizable DPWM oscillator, and most of the internal circuitry. The MAX1895/MAX1995 are available in the space-saving 28-pin thin QFN package and operate over the -40°C to +85°C temperature range.
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