The MAX8759 integrated cold-cathode fluorescent lamp
(CCFL) inverter controller is designed to drive CCFLs
using a full-bridge resonant inverter. The resonant operation
ensures reliable striking and provides near-sinusoidal
waveforms over the entire input range. The controller
operates over a wide input-voltage range of 4.5V to 28V
with high power to light efficiency. The device also
includes safety features that effectively protect against
single-point fault conditions such as lamp-out, secondary
overvoltage, and secondary short-circuit faults.
The MAX8759 provides accurate lamp-current regulation
(±2.5%) for superior CCFL inverter performance.
The lamp current is adjustable with an external resistor;
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 provides three mechanisms for
controlling brightness: 2-wire SMBus™-compatible
interface, external ambient-light sensor (ALS), or system
PWM control. The MAX8759 supports Intel display
power-saving technology (DPST) to maximize battery
life. The device includes two lamp-current feedback
input pins that support dual-lamp applications with a
minimum number of external components.
The MAX8759 controls a full-bridge inverter for maximum
efficiency and directly drives four external n-channel
power MOSFETs. An internal 5.35V linear regulator
powers the MOSFET drivers and most of the internal
circuitry. The MAX8759 is available in a space-saving,
28-pin, thin QFN package and operates over a -40°C to
+85°C temperature range.
Key Features
Applications/Uses
Accurate Dimming Control Using SMBus, PWM
Interface, or Ambient Light Sensor
10:1 Dimming Range with 256-Step Resolution
Resonant-Mode Operation
Longer Lamp Life with Near Sinusoidal Lamp-Current Waveform
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