Austriamicrosystems AS3645 LED闪光驱动方案
Austriamicrosystems公司的 AS3645是超小型高效单/双路LED闪光驱动器,它的DC/DC升压转换器工作频率高达2MHz,具有软起动功能,闪光停止,过压,超稳,欠压和LED短路保护功能.单路闪光LED电流高达700mA, 双路闪光LED电流高达1000mA,主要用于手机,数码相机和PDA的闪光/火炬.本文介绍AS3645主要特性, 内部方框图,以及典型工作电路图, 采用基带I2C模式, 照相机I2C模式和并行接口模式的应用电路图.
AS3645:1000/720mA Ultra Small High efficient single/dual LED Flash Driver with Safety Features
The AS3645 is an inductive high efficient DCDC step up converter with two current sources. The DCDC step up converter operates at a fixed frequency of 2MHz and includes soft startup to allow easy integration into noise sensitive RF systems. The two current sources (one for driving one or two flash LEDs and one for the indicator LED) can operate in flash / torch / assist (=video) light / indicator modes. If a two flash LEDs configuration is used, the LEDs are connected in series. Therefore identical current is guaranteed.
The AS3645 includes flash timeout, overvoltage, overtemperature, undervoltage and LED short circuit protection functions.
The AS3645 can be controlled either with parallel interface mode to allow simple integration. Alternatively it can be controlled by I2C mode to allow a more sophisticated..
