描述 Description

The MIC3291 is a PWM switching boost regulator that is optimized for constant current white LED (WLED) driver applications. The MIC3291 features an internal Schottky diode, allowing an efficient DC/DC solution that requires only four external components.The MIC3291 allows for a single-wire simple digital interface to control the dimming over 16 steps with a linear scale. The preprogramming feature allows the user to select any one of the 16 WLED current levels as the start up brightness level.The feedback voltage of the MIC3291 is only 250mV, allowing high efficiency while retaining excellent accuracy for the WLED current.The MIC3291 implements a constant frequency 1.2MHz PWM control scheme. The high frequency PWM operation saves board space by reducing external component sizes. The 1.2MHz PWM scheme also reduces switching noise and ripple to the input power source.The 2.5V to 6.5V input voltage range of the MIC3291 allows direct operation from single cell Li-Ion as well as 3- to 4-cell NiCad/NiMH/Alkaline batteries. Battery life is preserved with a low 1μA shutdown current.The MIC3291 is available in a low profile Thin SOT23 6-pin and 2mm x 2mm MLF??8-pin packages with a junction temperature range of -40°C to +125°C.

特性 Features

? Single wire combines 16 level linear brightness and shutdown control
? 18V/25V OVP options supports up to four and six WLEDs
? Startup in any one of 16 brightness levels
? Internal Schottky diode
? 2.5V to 6.5V input voltage
? 1.2MHz PWM operation
? Over 500mA switch current
? 250mV reference voltage
? ±5% LED current accuracy
? <1μA shutdown current
? UVLO and over-temperature protection
? Thin SOT23-6L package option
? 2mm x 2mm leadless MLF?package option
? -40°C to +125 °C junction temperature range

簡(jiǎn)介

MIC3291屬于集成電路（IC）的LED驅(qū)動(dòng)器。由制造生產(chǎn)的MIC3291LED 驅(qū)動(dòng)器器件屬于 LED 驅(qū)動(dòng)器電源管理集成電路 (PMIC) 系列，可通過(guò)標(biāo)稱固定電壓的電源為負(fù)載（通常為發(fā)光二極管）提供電流，并且電流可控。它與用于電壓調(diào)節(jié)的類(lèi)似產(chǎn)品的主要區(qū)別在于，這類(lèi)器件提供較低的反饋電壓（以提高系統(tǒng)能效），而且通?？蓪?duì)器件工作點(diǎn)進(jìn)行外部控制，可在照明應(yīng)用中用于實(shí)現(xiàn)調(diào)光功能。