Linear LT3593白光LED驱动方案

Linear 公司的LT3593是降压DC/DC转换器,用单节3V锂电池可驱动多达10个串联的白光LED,并具有.32:1的线性亮度控制范围,可广泛应用在手机,数码相机,PDA,手提计算机,MP3播放器和GPS接收器.本文介绍了LT3593的主要性能,方框图以及驱动不同数量LED的应用电路图.

The LT3593 is a step-up DC/DC converter designed to drive up to ten white LEDs in series from a Li-Ion cell.

Series connection of the LEDs provides identical LED currents and eliminates the need for ballast resistors. The device features a unique high side LED current sense that enables the part to function as a “one wire current source” where the low side of the LED string can be returned to ground anywhere.

Additional features include output disconnect in shutdown, open LED protection and 1-pin shutdown/LED current control. The CTRL pin is toggled to adjust the LED current via an internal counter and a 5-bit DAC.

The LT3593 switches at 1MHz, allowing the use of tiny external components. Constant frequency switching results in low input noise and a small output capacitor. The LT3593 is available in the 6-lead DFN (2mmX2mm) as well as the 6-lead SOT-23 packages.

主要特性:
Drives Up to Ten White LEDs from a 3V Supply
One Pin Shutdown and Current Programming
LEDs Disconnected in Shutdown..

查看全文