基于ADP8863設(shè)計(jì)的帶電荷泵驅(qū)動(dòng)的LED驅(qū)動(dòng)技術(shù)

ADP8863具有先進(jìn)的自治的LED光特性的功1強(qiáng)大的電荷泵驅(qū)動(dòng)器,能獨(dú)立地驅(qū)動(dòng)多達(dá)7個(gè)LED,每個(gè)電流高達(dá)30mA,第7個(gè)LED的驅(qū)動(dòng)電流可高達(dá)60mA.電荷泵的自動(dòng)增益選擇有1x,1.5x 和2x,工作電壓從2.5 V 到5.5 V,可驅(qū)動(dòng)最大電流240mA,主要用在LED指示器,裝飾指示照明,鍵盤(pán)照明,RGB LED色彩發(fā)生和藹混合以及小型顯示器通用照明.本文介紹ADP8863主要特性,詳細(xì)方框圖以及多種應(yīng)用電路.

The ADP8863 combines a powerful charge pump driver with advanced autonomous LED lighting features. It allows as many as seven LEDs to be independently driven up to 30 mA (maximum). The seventh LED can also be driven to 60 mA (maximum). All LEDs are programmable for maximum current and fade in/fade out times via the I2C interface.

Additionally, automated blinking routines can be independently programmed and enabled for all seven LED channels. These LEDs can also be combined into groups to reduce the processor instructions.

This entire configuration is driven by a two-capacitor charge pump with gains of 1×, 1.5×, and 2×. The charge pump is capable of driving a maximum IOUT of 240 mA from a supply of 2.5 V to 5.5 V. The device includes a variety of safety features including short-circuit, overvoltage, and overtemperature protection. These features allow easy implementation of a safe and robust design. Additionally, input inrush currents are limited via an integrated soft start combined with controlled input-to-output isolation.

The ADP8863 is available in a compact lead frame chip scale package (LFCSP).

ADP8863主要特性:

Automated blinking and funlight timing for each LED driver

16 programmable fade in and fade out times

0.1 sec to 5.5 sec

Selectable linear, square, or cubic fade rates

7 independent and programmable LED drivers

7 drivers capable of 30 mA (maximum)

1 driver also capable of 60 mA (maximum)

Programmable maximum current limit (128 levels)

Separate and independent controls for backlight LEDs

Backlight fade override

Up to two built-in comparator inputs with programmable modes for ambient light sensing

Charge pump with automatic gain selection of 1×, 1.5×, and 2× for maximum efficiency

Standby mode for <1 μA current consumption

I2C-compatible interface for all programming

Dedicated reset pin and built-in power-on reset (POR)

Short-circuit, overvoltage, and overtemperature protection

Internal soft start to limit inrush currents

Input-to-output isolation during faults or shutdown

Operation down to VIN = 2.5 V with undervoltage lockout (UVLO) at VIN = 2.0 V

Small lead frame chip scale package (LFCSP)

ADP8863應(yīng)用:

LED indication

Funlight indicator lighting

Keypad backlighting

RGB LED color generation and mixing

General backlighting of small format displays

圖1.ADP8863詳細(xì)方框圖

圖2.ADP8863典型工作電路框圖

圖3.ADP8863采用鎮(zhèn)流電阻給LED供電方框圖

圖4.ADP8863連接到ADP8861,給更多LED供電方框圖

圖5.用于低Vf LED的另一種應(yīng)用電路