NXPPCA963516位RGBA彩色LED驱动方案.docx

NXP PCA9635 16位RGBA彩色LED驱动方案 关键词：电源管理,LED驱动器,RGBA, PWM NXP 公司的PCA9635是I2C总线控制的16位红/绿/蓝/琥珀(RGBA)彩色LED驱动器,每个LED输出有8位分辨率(256级)的单独PWM控制器,工作频率97kHz,占空比从0%到99.6%可调,使LED设定特定的亮度.另外的8位分辨率群PWM控制器有固定频率190Hz和在24Hz到10.73秒的可调频率, 占空比从0%到99.6%可调. PCA9635主要用作RGB或RGBA LED驱动器,LED显示器,LCD背光以及手机或手提设备的键盘背景光.本文介绍了PCA9635主要特性, 方框图, 典型应用电路和开关时间测试电路.PCA9635: 16-bit Fm+ I2C-bus LED driverThe PCA9635 is an I2C-bus controlled 16-bit LED driver optimized for Red/Green/Blue/Amber (RGBA) color mixing applications. Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWM controller that operates at 97 kHz with a duty cycle that is adjustable from 0 % to 99.6 % to allow the LED to be set to a specific brightness value. An additional 8-bit resolution (256 steps) group PWM controller has both a fixed frequency of 190 Hz and an adjustable frequency between 24 Hz to once every 10.73 seconds with a duty cycle that is adjustable from 0 % to 99.6 % that is used to either dim or blink all LEDs with the same value.Each LED output can be off, on (no PWM control), set at its individual PWM controller value or at both individual and group PWM controller values. The LED output driver is programmed to be either open-drain with a 25 mA current sink capability at 5 V or totem-pole with a 25 mA sink, 10 mA source capability at 5 V. The PCA9635 operates with a supply voltage range of 2.3 V to 5.5 V and the outputs are 5.5 V tolerant. LEDs can be directly connected to the LED output (up to 25 mA, 5.5 V) or controlled with external drivers and a minimum amount of discrete components for larger current or higher voltage LEDs.The PCA9635 is one of the first LED controller devices in a new Fast-mode Plus (Fm+) family. Fm+ devices offer higher frequency (up to 1 MHz) and more densely populated bus operation (up to 4000 pF).The active LOW Output Enable input pin (OE) allows asynchronous control of the LED outputs and can be used to set all the outputs to a defined I2C-bus programmable