AIC1841中文资料High Efficiency 1.5x PWM Charge Pump For 4 White LEDs Backlighting数据手册AIC规格书

描述 Description

The AIC1841 and AIC1842 provide 4 and 6 LED current source outputs with regulated constant current for uniform intensity. The AIC1841/2 is the low noise, constant frequency charge pump DC/DC converter that uses 1.5X conversion to increase efficiency in white LED applications. The devices can be used to produce current levels up to 20mA for each output from a 2.7V to 5.5V input. Low external parts counts (two 1uF flying capacitors and two small bypass capacitors at VIN, and OUT) make the AIC1841/2 ideal for small, battery-powered applications.

EN/SET interface is used to enable, disable and set the LED current for a 32 level logic scale LED brightness control. Built-in current limiting, with thermal shutdown provide protection to the AIC1841/2 against fault conditions. Automatic soft-start circuitry prevents excessive inrush current during start-up. 1MHz high switching frequency is enable to use tiny external components.

The AIC1841 is available in a 12-pin thin QFN package, and the AIC1842 is available in a space-saving 16-pin QFN package.

特性 Features

• 1MHz Switching Frequency
• 2.7V to 5.5V Input Voltage Range
• Low Shutdown Current: ≦1μA
• Regulated 20mA Full-Scale Output Current
• 32-Position Linear Scale with Digital Control
• High Accuracy Brightness Matching
• 33% Less Input Current Than Doubler Charge Pump
• No Inductors Required
• Build-in Soft-Start
• Current Limit and Over Temperature Protection
• 12-Pin (AIC1841) and 16-Pin (AIC1842) QFN Package

应用 Application

• Cellular Phones
• PDAs
• Digital Still Cameras
• Handheld Devices
• White LED Backlighting