MCU

LP8551

SW

FB

VLDO

GNDs

EN

ISET

VDDIO

PWM

SCLK

SDA

OUT1

OUT2

OUT3

OUT4

L1

D1

10 V ± 40 V

5.5 V ± 22 V

5V

FSET

15 éH

210 mA ± 400 mA

COUT

CIN

10 éF

4.7 éF

CVLDO

1 éF

VDDIO reference voltage

FAULT

Can be left floating

if not used

39 pF

VIN

RISET

RFSET

VBATT

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LP8551

SNVS673E – APRIL 2010 – REVISED SEPTEMBER 2014

LP8551 High-Efficiency LED Backlight Driver for Notebooks

1 Features

3 Description

The LP8551 is a white LED driver with integrated

1

•

High-Voltage DC/DC Boost Converter with

boost converter. It has four adjustable current sinks

Integrated FET; Four Switching Frequency

which can be controlled by PWM input or with I2C-

Options: 156/312/625/1250 kHz

compatible serial interface.

•

2.7-V to 22-V Input Voltage Range to Support 1x

The boost converter has adaptive output voltage

to 5x Cell Li-Ion Batteries

control based on the LED driver voltages. This

•

50-mA High-Precision LED Current Sinks

feature

minimizes

the

power

consumption

by

•

Adaptive LED Current Sink Headroom Control for

adjusting the voltage to lowest sufficient level in all

Maximum System Efficiency

conditions.

•

Programmable PWM Resolution 8 to 13 Bits

LED outputs have 8-bit current resolution and up to

13-bit PWM resolution to achieve smooth and precise

•

I2C and PWM Input Duty Cycle Brightness Control

brightness control. Proprietary Phase Shift PWM

•

PWM Output Frequency and LED Current Set

control is used for LED outputs to reduce peak

Through Resistors

current from the boost converter, thus making the

•

4 LED Outputs with LED Fault (short/open)

boost capacitors smaller. The Phase Shifting scheme

Detection

also eliminates audible noise.

•

Low Input Voltage, Overtemperature, Overcurrent

Internal EEPROM is used for storing the configuration

Detection, and Shutdown

data. This makes it possible to have minimum

•

Minimum Number of External Components

external component count and make the solution very

small.

2 Applications

The LP8551 has safety features which make it

possible to detect LED outputs with open or short

•

Notebook and Tablet LCD Display LED Backlight

fault. As well, low input voltage and boost overcurrent

•

LED Lighting

conditions are monitored, and chip is turned off in

case of these events. Thermal de-rating function

prevents overheating of the device by reducing

backlight brightness when set temperature has been

reached.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (MAX)

LP8551

DSBGA (25)

2.49 mm x 2.49 mm

(1) For all available packages, see the orderable addendum at

the end of the datasheet.

Simplified Schematic

LED Drive Efficiency

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.