MP3011 – 1X, 1.5X, 2X AUTO-ADJUST CHARGE PUMP 2 WHITE LED DRIVER

MP3011 Rev. 1.1

www.MonolithicPower.com

5

10/31/2005

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© 2005 MPS. All Rights Reserved.

TM

OPERATION

The MP3011 is a charge pump that drives 2

LEDs from a 2.5V to 5.5V input voltage. It

automatically switches between 1x, 1.5x and 2x

charge pump modes to optimize efficiency while

maintaining LED current regulation.

Two drivers independently regulate the current

through the LEDs, therefore matching LEDs are

not required.

The MP3011 employs soft switching and

soft-start to prevent overloading the battery

source at turn-on as well as charge pump mode

switching.

While

operating,

the

MP3011

continually

monitors the LED current and battery voltage

and automatically switches between charge

pump modes to retain LED current regulation

through all LEDs as the battery voltage

fluctuates.

CURRENT

GENERATOR

CONTROLLER

LED

ENABLE

ISET

SHUTDOWN

RADJ

GND

EN

BATT

11

3, 10

12

5, 13

CHARGE PUMP

1.25V

BANDGAP

REFERENCE

BATTERY

SENSOR

PUMP

MODE

SOFT

START

LED2

LED1

FAULT

CURRENT

SOURCE

FAULT

CURRENT

SOURCE

C2B

BATT

ENABLE

C2A

C1B

C1A

LEDC

LED2

LED1

9

6

7

4

8

16

15

MP3011_F01_BD01

Figure 1—Functional Block Diagram