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LM3509

ACTIVE

High efficiency boost for white LED's and/or OLED displays with dual current sinks

Product details

Number of channels 2 Vin (min) (V) 2.7 Vin (max) (V) 5.5 Vout (min) (V) 0 Vout (max) (V) 21 Type Inductive Switching frequency (max) (kHz) 1250 Duty cycle (max) (%) 90 LED current per channel (mA) 30 Peak efficiency (%) 88 Topology Boost Features I2C control Operating temperature range (°C) -40 to 85 Rating Catalog
Number of channels 2 Vin (min) (V) 2.7 Vin (max) (V) 5.5 Vout (min) (V) 0 Vout (max) (V) 21 Type Inductive Switching frequency (max) (kHz) 1250 Duty cycle (max) (%) 90 LED current per channel (mA) 30 Peak efficiency (%) 88 Topology Boost Features I2C control Operating temperature range (°C) -40 to 85 Rating Catalog
WSON (DSC) 10 9 mm² 3 x 3
  • Integrated OLED Display Power Supply and LED Driver
  • Drives up to 10 LED’s at 30mA
  • Drives up to 5 LED’s at 20mA and Delivers up to 21V at 40mA
  • Over 90% Efficient
  • 32 Exponential Dimming Steps
  • 0.15% Accurate Current Matching Between Strings
  • Internal Soft-Start Limits Inrush Current
  • True Shutdown Isolation for LED’s
  • Wide 2.7V to 5.5V Input Voltage Range
  • 21V Over-Voltage Protection
  • 1.27MHz Fixed Frequency Operation
  • Low Profile 10-Pin WSON Package (3mm x 3mm x 0.8mm)
  • General Purpose I/O
  • Active Low Hardware Reset

All trademarks are the property of their respective owners.

  • Integrated OLED Display Power Supply and LED Driver
  • Drives up to 10 LED’s at 30mA
  • Drives up to 5 LED’s at 20mA and Delivers up to 21V at 40mA
  • Over 90% Efficient
  • 32 Exponential Dimming Steps
  • 0.15% Accurate Current Matching Between Strings
  • Internal Soft-Start Limits Inrush Current
  • True Shutdown Isolation for LED’s
  • Wide 2.7V to 5.5V Input Voltage Range
  • 21V Over-Voltage Protection
  • 1.27MHz Fixed Frequency Operation
  • Low Profile 10-Pin WSON Package (3mm x 3mm x 0.8mm)
  • General Purpose I/O
  • Active Low Hardware Reset

All trademarks are the property of their respective owners.

The LM3509 current mode boost converter offers two separate outputs. The first output (MAIN) is a constant current sink for driving series white LED’s. The second output (SUB/FB) is configurable as a constant current sink for series white LED bias, or as a feedback pin to set a constant output voltage for powering OLED panels.

All trademarks are the property of their respective owners.

When configured as a dual output white LED bias supply, the LM3509 adaptively regulates the supply voltage of the LED strings to maximize efficiency and insure the current sinks remain in regulation. The maximum current per output is set via a single external low power resistor. An I2C compatible interface allows for independent adjustment of the LED current in either output from 0 to max current in 32 exponential steps. When configured as a white LED + OLED bias supply the LM3509 can independently and simultaneously drive a string of up to 5 white LED’s and deliver a constant output voltage of up to 21V for OLED panels.

Output over-voltage protection shuts down the device if VOUT rises above 21V allowing for the use of small sized low voltage output capacitors. The LM3509 is offered in a small 10-pin thermally- enhanced WSON package and operates over the -40°C to +85°C temperature range.

The LM3509 current mode boost converter offers two separate outputs. The first output (MAIN) is a constant current sink for driving series white LED’s. The second output (SUB/FB) is configurable as a constant current sink for series white LED bias, or as a feedback pin to set a constant output voltage for powering OLED panels.

All trademarks are the property of their respective owners.

When configured as a dual output white LED bias supply, the LM3509 adaptively regulates the supply voltage of the LED strings to maximize efficiency and insure the current sinks remain in regulation. The maximum current per output is set via a single external low power resistor. An I2C compatible interface allows for independent adjustment of the LED current in either output from 0 to max current in 32 exponential steps. When configured as a white LED + OLED bias supply the LM3509 can independently and simultaneously drive a string of up to 5 white LED’s and deliver a constant output voltage of up to 21V for OLED panels.

Output over-voltage protection shuts down the device if VOUT rises above 21V allowing for the use of small sized low voltage output capacitors. The LM3509 is offered in a small 10-pin thermally- enhanced WSON package and operates over the -40°C to +85°C temperature range.

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Technical documentation

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Type Title Date
* Data sheet HE Boost for White LED's / OLED Displays w/ Dual Sinks & I2C Brightness Control datasheet (Rev. D) 03 May 2013
White paper Common LED Functions and LED Driver Design Considerations 21 Sep 2020
Technical article How energy harvesting can extend the life of your fault indicator on the grid PDF | HTML 18 Oct 2017
Application note Analog PWM Dimming in White-LED Drivers 21 Dec 2016
EVM User's guide AN-1594 LM3509 Evaluation Board (Rev. A) 30 Apr 2013

Design & development

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Evaluation board

LM3509SDEV — LM3509SD Evaluation Board

The LM3509 current mode boost converter offers two separate outputs. The first output (MAIN) is a constant current sink for driving series white LED's. The second outut (SUB/FB) is configurable as a constant current sink for series white LED bias, or as a feedback pin to set a constant output (...)

User guide: PDF
Not available on TI.com
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Reference designs

TIDA-00998 — Energy Harvesting and Fault Indicator Subsystem for Overhead Fault Indicators Reference Design

This reference design shows multiple architectures for extending primary battery life using a secondary battery or supercapacitor with energy harvested from a current transformer (CT) or solar cells. Optimal power management is done using efficient LED drivers to drive series or parallel (...)
Design guide: PDF
Schematic: PDF
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WSON (DSC) 10 Ultra Librarian

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