AAT3132ITP-1-T1 View Datasheet(PDF) - Analog Technology Inc

Part Name

Description

MFG CO.

AAT3132ITP-1-T1

High Efficiency 1.5X Fractional Charge Pump for White LED Applications

Analog Technology Inc 

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AAT3132/32A

High Efficiency 1.5X Fractional Charge

Pump for White LED Applications

However, if the diodes are dramatically different in

type comprising a mix of high-VF type and low-VF

type LEDs, the AAT3132/32A has the capability to

optimally drive up to four LEDs of one type and up

to two LEDs of another type simultaneously. This

feature can be useful for driving different color

LEDs, driving both display backlight and photo-

flash LEDs, or for driving main and sub-LCD dis-

play LED backlights from a single charge pump IC.

For example, when driving independent RGB

LEDs, the green and blue LEDs typically require a

high VF to operate (e.g., 3.7V), while the red LED

needs a low forward voltage (e.g., 2V). By con-

necting the green and blue diodes to outputs D1 to

D3 and the red diodes to D4, good control and uni-

formity in brightness is maintained despite the 2V

difference in the diode forward voltages.

Similarly, if a 4V photo-flash LED array is connect-

ed to outputs D1 through D3 (with the outputs short-

ed together) and two 3.3V sub-LCD display back-

light LEDs are connected to output D4, then the

AAT3132/32A can optimally drive each set of LEDs

at the programmed current level (see Figure 2).

VBATTERY

VIN

C1+

C1

1µF

VOUT

C1-

C2+

CIN

COUT

AAT3132

C2

1µF

1µF

AAT3132A

1µF

C2-

D1

D2

D3

EN/SET

EN/SET D4

GND

D1

D2

D3

D4

D5

D6

Figure 2: AAT3132/32A Driving Two Groups of Paralleled White LEDs

(e.g., main and sub-LCD backlights).

3132.2005.12.1.4

13

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