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MP1521EK-LF-Z

High Efficiency White LED Driver

Monolithic Power Systems 

Monolithic Power Systems

MP1521

High Efficiency

White LED Driver

General Description

The MP1521 is a constant-current Boost

Regulator. This IC has three individual

current-sensing feedbacks, which are ideal for

driving multiple strings of series connected

LEDs. The OLS pin is designed for detecting

loose or open LED connections.

The IC uses a peak current, constant minimum

off-time architecture. The feedback pins

measure voltage across sense resistors in

series with the LED strings. When supplying a

bias current of 20mA, the voltage drop across

the sense resistor is only 0.4V to minimize

power loss. Either a DC voltage or a PWM

signal at the BRT/PWM input can control the

LED brightness.

The MP1521 has an on board power MOSFET

switch that is protected by current limit, open

load shutdown, thermal shutdown, and under

voltage lockout.

Ordering Information

Part Number ∗

MP1521EK

Package

MSOP10

Temperature

-20° to +85°C

MP1521EQ

QFN16 (3x3) -20° to +85°C

EV0005

MP1521EK Evaluation Board

EV0021

MP1521EQ Evaluation Board

∗ For Tape & Reel, add suffix –Z (i.e., MP1521EK–Z)

For Lead Free, add suffix –LF (i.e., MP1521EK–LF–Z)

Features

ƒ On Board Power MOSFET

ƒ Drive 9 White LEDs from 2.7V Input

ƒ Drive 15 White LEDs from 5V Input

ƒ Up to 90% Efficiency

ƒ Over 80mA Output Current Capacity

ƒ Open Load Shutdown

ƒ Low Current Sensing Feedback Voltage

ƒ Up to 3 String Current Sensing Feedback

ƒ Analog and Digital PWM Brightness Control

ƒ UVLO, Thermal Shutdown

ƒ Soft Start

ƒ Internal Current Limit

ƒ Available in Compact MSOP10 and

Tiny 3 mm x 3 mm QFN16 Package

ƒ Evaluation Boards Available

Applications

ƒ Handheld Computers, Cell phones, PDAs,

Digital and Video Cameras, Small LCD

Displays

ƒ Li Ion and NiMH Battery Applications

Typical Application Circuit (One String of Six (6) LEDs)

1 IN

L1

D1

SW 10

ON

MP1521

COUT

OFF

EN 2 EN

GND 9

3 REF

BRT/

PWM

4 BRT/PWM

OLS 8

FB1 7

White LEDs

5 FB3

FB2 6

VIN

CIN

GND

Efficiency vs LED current, 1 string of 6

Using Toko D62CB 47µH Inductor

100

90

VIN = 5V

80

VIN = 4V

70

VIN = 3V

60

50

5 10 15 20 25

LED Current (mA)

MP1521 Rev 2.7 10/06/04

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