白光LED驱动翻盖手机

摘要：开关转换器集成电路设计为白光LED驱动器和一个模拟开关控制LED照明在移动手机（翻盖）三种形式。

Maxim > App Notes > SWITCHES AND MULTIPLEXERS

Keywords: mobile phones, clamshell phones, white LEDs, keyboard illumination Sep 23, 2005

APPLICATION NOTE 3624
Driving White LEDs in Clamshell Phones

Abstract: A switching-converter IC―designed as a white-LED driver―and an analog switch control three forms
of LED illumination in a mobile (clamshell) phone.

This circuit multiplexes the drive to three sets of LEDs found inside clamshell phones. These phones usually have
an external display that is illuminated when an incoming telephone call occurs. Once the clamshell is opened, the
external display illumination is switched off and the main internal display and keyboard illumination are activated.

The circuit in Figure 1 is based around the MAX1848 (IC1) white LED dr