Simplified Block Diagram
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- 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
- Guaranteed Striking Capability
- High-Power-to-Light Efficiency
- Wide Input-Voltage Range (4.5V to 28V)
- Input Feed-Forward for Excellent Line Rejection
- ±2.5% Lamp-Current Regulation
- Adjustable 1.5% Accurate DPWM Frequency
- Dual Lamp-Current Feedback Inputs
- Comprehensive Fault Protection
- Secondary Voltage Limiting
- Primary Current Limit with Lossless Sensing
- Lamp-Out Protection with Adjustable Timeout
- Secondary Short-Circuit Protection
- Small 28-Pin, 5mm x 5mm, Thin QFN Package
- LCD Monitors
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.