照明控制應(yīng)用的LED驅(qū)動(dòng)器

　　ROHM提供許多外部和集成輸出LED驅(qū)動(dòng)器應(yīng)用范圍廣。

　　由于種種原因，發(fā)光二極管的使用正在增加。與白熾燈相比，LED更高效、體積更小、壽命更長(zhǎng)，可以為改進(jìn)美學(xué)提供更大的設(shè)計(jì)自由度。此外，LED照明的顏色更自然，使其成為照明的首選。易于控制的LED也使它們成為基于傳感器輸入的智能照明系統(tǒng)的自然選擇。控制的一個(gè)重要方面是集成電路驅(qū)動(dòng)程序提供的電源管理。

　　LED驅(qū)動(dòng)能力

　　LED需要恒定電流才能產(chǎn)生一致的照明。因此，這就構(gòu)成了LED驅(qū)動(dòng)器的基本操作要求。電流源的準(zhǔn)確性決定了它的客戶吸引力。電流波動(dòng)可能隨著電壓供應(yīng)的變化而發(fā)生，必須避免。線性穩(wěn)壓器提供一個(gè)簡(jiǎn)單的控制，不需要電磁干擾（EMI）濾波器。然而，它們的功耗可能會(huì)變得更高功率應(yīng)用。降壓DC-DC轉(zhuǎn)換器通常作為下一步從一個(gè)線性穩(wěn)壓器。

　　When the driver must control several LEDs in series， a boost converter topology is used. In some cases， a buck-boost topology provides the capability to address a variety of application requirements， including the ability to handle voltage extremes.

　　LED drivers can be designed to offer a combination of series and parallel LED control. Devices with this capability built-in provide circuit designers the flexibility to control LEDs in different applications with a single driver， rather than requiring different devices that increase qualification testing. Dimming the light level is a common requirement for lighting. However， there are applications for brighter than normal requirements from the same LEDs. In some cases， lighting design may be able to address both situations with the same LEDs with the right LED driver.