AAT3166IWP-T1 View Datasheet(PDF) - Analog Technology Inc

Part Name

Description

MFG CO.

AAT3166IWP-T1

High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications

Analog Technology Inc 

1 2 3 4 5 6 7 8 9 10 Next

Functional Block Diagram

AAT3166

High Efficiency 1X/1.5X/2X Charge

Pump for White LED Applications

C1+ C1- C2+ C2-

IN

EN/SET

Soft-Start

Control

1MHz

Oscillator

Voltage

Reference

AS2Cwire

Interface

1X, 1.5X, 2X

Charge Pump

D/A

6 x 16 Bit

ROM

D/A

D/A

6 x 16 Bit

ROM

D/A

OUTCP

D1

D2

D3

D4

GND

Functional Description

The AAT3166 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 AAT3166

charge pump is enabled when any of the four cur-

rent sink inputs near dropout. The charge pump

initially starts in 1.5X mode. If the charge pump

output drops enough for any current source output

to become close to dropout, the charge pump will

automatically transition to 2X mode. The AAT3166

requires only four external components: two 1µF

ceramic capacitors for the charge pump flying

8

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

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

charge pump output capacitor (COUT).

The four constant current sink inputs (D1 to D4)

can drive four individual LEDs with a maximum cur-

rent of 27mA nominal each. Unused sink inputs

should be connected to OUTCP, otherwise the part

will operate only in 2X charge pump mode. The

AS2Cwire serial interface enables the AAT3166

and sets the current sink magnitudes. AS2Cwire

addressing allows independent control of two

groups of current sink input: D1~D3 and D4.

Constant Current Output Level Settings

The constant current sink levels for D1 to D4 are

set via the serial interface according to a logarith-

mic scale where each code is approximately 1.8dB

lower than the previous code. In this manner, LED

3166.2006.05.1.2

Share Link: