AAT3153 Datasheet, PDF(8/14 Page) Advanced Analogic Technologies – High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications

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AAT3153 Datasheet, PDF (8/14 Pages) Advanced Analogic Technologies – High Efficiency 1X/1.5X/2X Charge Pump For White LED Applications

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Functional Block Diagram

AAT3153

High Efficiency 1X/1.5X/2X Charge Pump

For White LED Applications

C1+ C1- C2+ C2-

VIN

EN/SET

Soft-Start

Control

1MHz

Oscillator

Voltage

Reference

S2Cwire

Interface

1X, 1.5X, and 2X

Charge Pump

D/A

6 x 16 bit

ROM

D/A

6 x 16 bit

D/A

ROM

D/A

VOUT

Functional Description

The AAT3153 is a tri-mode load switch (1X) and

high efficiency (1.5X or 2X) charge pump device

intended for white LED backlight applications. To

maximize power conversion efficiency, an internal

sensing circuit monitors the voltage required on

each constant current sink input and sets the load

switch and charge pump modes based on the input

battery voltage and the current sink input voltage.

As the battery discharges over time, the AAT3153

charge pump is enabled when any of the four cur-

rent sink inputs near dropout. The charge pump ini-

tially starts in 1.5X mode. If the charge pump out-

put drops enough for any current source output to

become close to dropout, the charge pump will

automatically transition to 2X mode. The AAT3153

requires only four external components: two 1ÂµF

ceramic capacitors for the charge pump flying

capacitors (C1 and C2), one 1ÂµF ceramic input

capacitor (CIN), and one 0.33ÂµF to 1ÂµF ceramic

charge pump output capacitor (COUT).

3153.2005.12.0.93

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