MAXIM Integrated Products has released a fan integrated backlight controller, available from Arrow Electronics . The MAX8709 is optimised for powering cold-cathode fluorescent lamps (CCFLs) by using a resonant, full bridge inverter architecture.
To improve CCFL lifetime, the resonant operation maximises striking capability and provides near-sinusoidal waveforms over the entire input range. The controller operates over a wide input voltage range of 4.6V to 28V, with high power to light efficiency.
The MAX8709 integrates safety features for protection against many single-point fault conditions, including lamp-out and short-circuit faults. This makes it suited for notebook-computer displays, LCD TVs and monitors, and automotive displays.
The MAX8709 achieves a 10:1 dimming range by chopping the lamp current on and off using a digitally adjusted, pulse width modulation (DPWM) method. The brightness is controlled with a two wire SMBus-compatible interface. The device directly drives the full-bridge inverter's four external N-channel power MOSFETs. An internal 5.3V linear regulator powers the MOSFET drivers, the DPWM oscillator, and most of the internal circuitry.
The MAX8709 is available in a space-saving 28-pin TQFN package and operates over the 40°C to +85°C extended temperature range.