白光LED驱动芯片 SN3228A SN3228B

                                       白光LED驱动--RT9284

       RT9284为一*率升压(boost)白光LED驱动IC，可以同时驱动4颗串联白光LED以及支持100Hz to 100KHz的微控频率，这样即可*避免噪音产生。另外，当白光LED出现异常情况下，具有过电压保护功能的RT9284可以*保护其周边元器件。

       RT9284采用薄型SOT封装，使用者可以大幅减低所需板裁面积。

                                         白光LED驱动IC--SN3228

Applications

l   White LED backlighting

l   Mp3, Mp4, PMP

l   Cell phone, *art phone, PDA

 Features

l  UTQFN-12 (2mm × 2mm ) package

l  Low shutdown current: ISHDN <3μA

l  Automatic soft start

l  Built-in thermal protection

l  No inductors, low noise operation
l  Drives up to four (SN3228A)/six (SN3228B) channels of LEDs -14 current levels
l  Fully programmable current with single wire

l  VCC range: 2.8V to 5.5V
Description

     The SN3228A (SN3228B) is a low noise, constant frequency charge pump DC/DC converter for white LED applications. The SN3228A (SN3228B) is capable of driving up to four (six) channels of LEDs at preset 20mA per channel from a 2.8V to 5.5V input. The current sinks may be operated individually or in parallel for driving higher current LEDs. Only one 1μF *all capacitor (at C thru C-) and two *all 2.2μF capacitors (at VCC and VOUT) are needed, it makes this part ideally suited for *all, battery-powered applications.

      The serial di*al input is used to enable, disable, and set current for each LED with 14 settings down to 1.8mA. Each output of the SN3228A/SN3228B is equipped with built-in soft-start circuitry prevents excessive inrush current during start-up. A low-current shutdown feature disconnects the load from the input and reduces quiescent current to less than 3μA.The SN3228A and SN3228B are available in a Pb-free, space-saving 2mm × 2mm UTQFN-12 package.