LP8545SQE/NOPB National Semiconductor, LP8545SQE/NOPB Datasheet

LP8545SQE/NOPB

Manufacturer Part Number

LP8545SQE/NOPB

Description

IC LED BACKLIGHT DRIVER LLP-24

Manufacturer

National Semiconductor

Datasheet

1.LP8545SQXNOPB.pdf (4 pages)

Specifications of LP8545SQE/NOPB

Internal Driver

Yes

Type - Primary

Backlight

Type - Secondary

White LED

Mounting Type

Surface Mount

Topology

PWM, Step-Up (Boost)

Number Of Outputs

Frequency

Adjustable/Selectable

Voltage - Supply

2.7 V ~ 22 V

Package / Case

24-WFQFN Exposed Pad

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Voltage - Output

Operating Temperature

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High-Efficiency LED Backlight Driver for Notebooks

General Description

The LP8545 is a white LED driver with integrated boost con-

verter. It has six adjustable current sinks which can be con-

trolled by PWM input or with I

The boost converter has adaptive output voltage control

based on the LED driver voltages. This feature minimizes the

power consumption by adjusting the voltage to lowest suffi-

cient level in all conditions.

LED outputs have 8-bit current resolution and up to 13-bit

PWM resolution with additional 1-3 bit dithering to achieve

smooth and precise brightness control. Proprietary Phase

Shift PWM control is used for LED outputs to reduce peak

current from the boost converter, thus making the boost ca-

pacitors smaller. The Phase Shifting scheme also eliminates

audible noise.

Internal EEPROM is used for storing the configuration data.

This makes it possible to have minimum external component

count and make the solution very small.

LP8545 has safety features which make it possible to detect

LED outputs with open or short fault. As well low input voltage

and boost over-current 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.

LP8545 is available in National's LLP-24 package.

NOTICE: This document is not a full datasheet. For more

information regarding this product or to order samples,

please contact your local National Semiconductor sales

office or visit http://www.national.com/support/dir.html.

Typical Application (1)

C-compatible serial interface.

LP8545 PRODUCT BRIEF

301084

Features

■

Applications

■

High-voltage DC/DC boost converter with integrated FET

with four switching frequency options: 156/312/625/1250

kHz

Configurable for use with external FET for applications

needing higher output voltage

2.7V – 22V input voltage range to support 1x…5x cell Li-

Ion batteries

Programmable PWM resolution

-8 to 13 true bit (steady state)

-Additional 1 to 3 bits using dithering during brightness

changes

PWM output frequency and LED current set through

resistors

Optional synchronization to display V

6 LED outputs with LED fault (short/open) detection

Low input voltage, over-temperature, over-current

detection and shutdown

Minimum number of external components

LLP-24 package, 4 x 4 x 0.8 mm

Notebook and Netbook LCD Display LED Backlight

LED Lighting

C and PWM brightness control

SYNC

30108470

signal

April 23, 2010

www.national.com

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LP8545SQE/NOPB Summary of contents

Page 1

... LP8545 is available in National's LLP-24 package. NOTICE: This document is not a full datasheet. For more information regarding this product or to order samples, please contact your local National Semiconductor sales office or visit http://www.national.com/support/dir.html. Typical Application (1) © 2010 National Semiconductor Corporation ...

Page 2

www.national.com 2 ...

Page 3

Typical Application for Low Input Voltage (2) Note: Separate 5V rail to V can be also used to improve efficiency for applications with higher battery voltage. No power LDO sequencing requirements between Typical Application for High Output ...

Page 4

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...

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