BCT3221数据手册Broadchip中文资料规格书

描述 Description

The BCT3221 is a high performance white LED driver. The BCT3221 uses an internal resistor to set the bias current for four LEDs, which are matched to +/-1.5%. The BCT3221's advantages over ballast resistors include much lower bias variation with supply voltage variation, significantly lower dropout voltage, and in some applications, significantly improved efficiency. The BCT3221 requires only a 50mV dropout voltage at a 20mA load on each output to match the LED brightness. By using one SEL pin, the BCT3221 can support to drive 4 parallel Co-Anode or Co-Cathode white LEDs and regulates a constant current for uniform intensity.
Users can easily configure the LED current from 2.5mA to 20mA by a serial pulse. The dimming of white LEDs current can be achieved by applying a pulse signal to the EN pin. There are totally 8 steps of current could be set by users. Internal soft start circuitry effectively reduces the in-rush current while both start-up and mode transition.

特性 Features

·♦ Drive Common Anode or Common Cathode LEDs
·♦ Low 50mV Dropout at 20mA
·♦ 20mA full scale current
·♦♦ One Wire interface for 8-Step Brightness Control
·♦ 2.7V to 5.5V Supply Voltage Range
·♦ Thermal Shutdown Protection
·♦ Low Input Noise and EMI
·♦ RoHS Compliant QFN-16L Package

应用 Application

Cell Phones/PDAs/Digital Cameras/Camcorders/Portable Instrumentation/Battery Powered Equipment