SMBus CCFL Backlight Controller Provides Superior Fault Protection and Lamp-Current Regulation
SUNNYVALE, CA-November 15, 2005-Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX8759, an integrated inverter controller designed to drive cold-cathode fluorescent lamps (CCFLs) using a full-bridge resonant inverter for maximum efficiency. Input power is converted to light with high efficiency. Safety features effectively protect against single-point fault conditions such as lamp-out, secondary overvoltage, and secondary short-circuit faults. Brightness is controlled through three mechanisms: a 2-wire SMBus™-compatible interface, an external ambient light sensor (ALS), or system PWM control.
The MAX8759 provides ±2.5% accurate lamp-current regulation, adjustable with an external resistor, for superior CCFL inverter performance. A 10:1 dimming range can be achieved by turning the CCFL on and off using a digital pulse-width modulation (DPWM) method, while maintaining the lamp current constant. The MAX8759 supports Intel® display power-saving technology (DPST) to maximize battery life and includes two lamp-current feedback input pins that support dual-lamp applications with a minimum number of external components.
An internal 5.35V linear regulator powers most of the internal circuitry and the MOSFET driver, which directly drives four external n-channel power MOSFETs. The resonant operation ensures reliable striking and provides near-sinusoidal waveforms over the entire 4.5V to 28V input range.
The MAX8759 is available in a space-saving (5mm x 5mm), low-profile (0.8mm), 28-pin thin QFN package and operates over the -40°C to +85°C temperature range. Prices start at $4.23 (1000-up, FOB USA). A preassembled MAX8759 EV kit is available with recommended external components to reduce design time.
SMBus is a trademark of Intel Corp.
Intel is a registered trademark of Intel Corp.
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