LM3530 Datasheet, PDF (1/4 Pages) National Semiconductor (TI) – High Efficiency White LED Driver with Programmable Ambient Light Sensing Capability and I2C Compatible Interface

LM3530 PRODUCT BRIEF
November 29, 2010
High Efficiency White LED Driver with Programmable
Ambient Light Sensing Capability and I²C Compatible
Interface
General Description
The LM3530 current mode boost converter supplies the pow-
er and controls the current in up to 11 series white LED’s. The
839mA current limit and 2.7V to 5.5V input voltage range,
makes the device a versatile backlight power source ideal for
operation in portable applications.
The LED current is adjustable from 0 to 29.5mA via an I²C
compatible interface. The 127 different current steps and 8
different maximum LED current levels give over 1000 pro-
grammable LED current levels. Additionally, PWM brightness
control is possible through an external logic level input.
Additionally, the device features two Ambient Light Sensor
inputs. These are designed to monitor analog output ambient
light sensors and provide programmable adjustment of the
LED current with changes in ambient light. Each ambient light
sensor input has independently programmable internal volt-
age setting resistors which can be made high impedance to
reduce power during shutdown. The LM3530's 500kHz
switching frequency allows for high converter efficiency over
a wide output voltage range accommodating from 2 to 11 se-
ries LEDs. Finally, the support of Content Adjusted Backlight-
ing maximizes battery life while maintaining display image
quality.
The LM3530 is available in a tiny 12-bump (1.6mm × 1.2mm
× 0.425mm) micro SMD package and operates over the -40°
C to +85°C temperature range.
Notice: This document is not a full datasheet. For more
imformation regarding this product, or to order samples,
please contact your National Semiconductor sales office
or visit http://www.national.com/support/dir.html.
Features
■ ^{Drives up to 11 LED’s in series}
■ ^{1000:1 Dimming Ratio}
■ ^{90% Efficieny}
■ ^{Programmable Dual Ambient Light Sensor Inputs with}
internal ALS Voltage Setting Resistors
■ ^{I2C Programmable Logarithmic or Linear Brightness}
Control
■ ^{External PWM Input for Simple Brightness Adjustment}
■ ^{True Shutdown Isolation for LED's and Ambient Light}
Sensors
■ ^{Internal Soft-Start Limits Inrush Current}
■ ^{Wide 2.7V to 5.5V Input Voltage Range}
■ ^{40V Over-Voltage Protection}
■ ^{500 kHz Fixed Frequency Operation}
■ ^{839mA Peak Current Limit}
■ ^{Low Profile 12-bump micro SMD Package}
Applications
■ ^{Smartphone LCD Backlighting}
■ ^{Personal Navigation LCD Backlighting}
■ ^{2 to 11 series White LED Backlit Display Power Source}
LM3530 Layout Example
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