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Product details

Parameters

Input voltage (type) AC/DC Vin (Min) (V) 8 Vin (Max) (V) 12 Iout (Max) (A) 2 Vout (Min) (V) 9 Vout (Max) (V) 60 Regulated outputs (#) 1 Topology Buck, Flyback Dimming method Forward Phase (Triac), PWM, Reverse Phase Power factor correction (Min) Active, Passive Features Adjustable Switch Frequency, Enable/Shutdown, Thermal Shutdown Operating temperature range (C) -40 to 125 Switching frequency (Min) (kHz) 30 Switching frequency (Max) (kHz) 1000 Iq (Typ) (mA) 2 Vref (V) 0.75 open-in-new Find other General lighting LED drivers

Package | Pins | Size

SOIC (D) 14 52 mm² 8.65 x 6 VSSOP (DGS) 10 9 mm² 3 x 3 open-in-new Find other General lighting LED drivers

Features

  • TRIAC Dim Decoder Circuit for LED Dimming
  • Application Voltage Range 80 VAC to 277 VAC
  • Capable of Controlling LED Currents Greater
    Than 1 A
  • Adjustable Switching Frequency
  • Low Quiescent Current
  • Adaptive Programmable Off-Time Allows for
    Constant Ripple Current
  • Thermal Shutdown
  • No 120-Hz Flicker
  • Low Profile 10-Pin VSSOP Package or 14-Pin
    SOIC
  • Patented Drive Architecture
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Description

The LM3445 is an adaptive constant off-time AC/DC buck (step-down) constant current controller designed to be compatible with TRIAC dimmers. The LM3445 provides a constant current for illuminating high power LEDs and includes a TRIAC dim decoder. The dim decoder allows wide range LED dimming using standard TRIAC dimmers. The high frequency capable architecture allows the use of small external passive components. The LM3445 includes a bleeder circuit to ensure proper TRIAC operation by allowing current flow while the line voltage is low to enable proper firing of the TRIAC. A passive PFC circuit ensures good power factor by drawing current directly from the line for most of the cycle, and provides a constant positive voltage to the buck regulator. Additional features include thermal shutdown, current limit and VCC under-voltage lockout.

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Technical documentation

= Top documentation for this product selected by TI
No results found. Please clear your search and try again. View all 17
Type Title Date
* Datasheet LM3445 TRIAC Dimmable Offline LED Driver datasheet (Rev. M) Nov. 30, 2015
White papers Common LED Functions and LED Driver Design Considerations Sep. 21, 2020
Selection guides Power Management Guide 2018 (Rev. R) Jun. 25, 2018
Technical articles Here's how body electronics and lighting technology are changing the driving experience Sep. 26, 2016
Technical articles LED brightness adjustment: high-frequency PWM dimming Aug. 26, 2016
User guides 120Vac Valley Fill Buck Triac Dimmable LED Driver May 12, 2015
Technical articles Take better selfies with innovative LED flashes Nov. 18, 2014
Technical articles Solving the automotive EMI issues in new cars with all the screens Sep. 10, 2014
Application notes AN-1656 Design Challenges of Switching LED Drivers (Rev. A) May 03, 2013
User guides AN-1935 LM3445 Off-Line TRIAC Dimmer LED Driver Demo Board (Rev. I) May 01, 2013
User guides AN-1978 LM3445 120VAC Small Evaluation Board (Rev. G) May 01, 2013
User guides AN-1995 LM3445 208-277V AC Non-Isolated Evaluation PCB (Rev. B) May 01, 2013
Application notes AN-2034 LM3445 -120VAC, 8W Isolated Flyback LED Driver (Rev. C) May 01, 2013
User guides AN-2061 LM3445 A19 Edison Retrofit Evaluation Board (Rev. C) May 01, 2013
Application notes An Improved Line Regulation Solution Used in LM3444/5 Non-Isolated LED Lighting Oct. 25, 2012
User guides 230 Vac Off-line Triac Dimmer Retrofit with 6 LEDs Reference Design User Guide Jan. 27, 2012
Application notes AN-2069 LM3445 - 230VAC, 6W- 15W Isolated Flyback LED Driver (Rev. B) Nov. 23, 2010

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

EVALUATION BOARDS Download
79
Description

This demonstration board highlights the performance of a LM3445 based Flyback LED driver solution that can be used to power a single LED string consisting of 4 to 8 series connected LEDs from an 90 VRMS to 135 VRMS, 60 Hz input power supply. The key performance characteristics under typical (...)

Features
  • Drop-in compatibility with TRIAC dimmers
  • Line injection circuitry enables PFC values greater than 0.95
  • Adjustable LED current and switching frequency
  • Flicker free operation

Applications:

  • Retro-fit TRIAC Dimming
  • Solid State Lighting
  • Industrial and Commercial Lighting
  • Residential Lighting

 

EVALUATION BOARDS Download
document-generic User guide
79
Description

The evaluation board included in this shipment converts 85VAC to 135VAC input and drives five to thirteen series connected LED`s at the currents listed in the Evaluation Board Operating Conditions section. This is a two-layer board using the bottom and top layer for component placement. The board is (...)

EVALUATION BOARDS Download
document-generic User guide
49
Description

The LM3445EVM-695 implements a dimming solution using the LM3445 integrated circuit from Texas Instruments. The LM3445 is an adaptive constant off-time AC/DC buck constant current controller with built in phase dimming decoder. Line cycles are analyzed continuously by an internal low power digital (...)

Features
  • Constant Current Buck LED Driver
  • 120Vac Nominal Input
  • Triac Dimmable
  • Good Line Regulation
  • Small Form Factor

Design tools & simulation

SIMULATION TOOLS Download
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — 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 (...)
Features
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)

Reference designs

REFERENCE DESIGNS Download
230 V in to 180 V out at 200 mA constant-current LED driver reference design
PMP30439 — This reference design is a low-side Buck (the output voltage is referenced to the positive DC input (+Vin node), not to the GND node). The controller drives a LED string up to 180V with 200mA constant current. The low-side Buck topology simplifies the schematic thanks to direct-driving of the FET (...)
document-generic Schematic document-generic User guide
REFERENCE DESIGNS Download
230V AC input to 23V,0.42A Flyback LED Driver
PMP7752 — It is a TRAIC dimmable offline flyback LED driver using LM3445. It has an adaptive constant off-time AC/DC constant current controller feature. It can be used with input supply of 230V AC and can light 7 LEDs in string supplying 420mA of current.
REFERENCE DESIGNS Download
Non-isolated Dimmable LED Driver with improved line regulation
PMP4327A — This reference design demonstrates a high efficiency non-isolated dimmable LED driver solution using LM3445. With additional feed-forward circuit, improved line regulation <+/-2% performance is achieved. The input range is 90~132Vac and output is 40V310mA.
Design files
REFERENCE DESIGNS Download
230 Vac Off-line Triac Dimmer Retrofit with 6 LEDs Reference Design
LM3445-REF The main purpose of the power supply is to convert the rectified AC Input to DC regulated current for 6 LEDs.  The power supply provides protection for the LEDs, limits the transient input voltage and protect against inrush current at plug in.  The overall power supply conformity (e.g (...)
REFERENCE DESIGNS Download
120V AC input and 24.5V output LED Driver
PMP7770 — It is an offline AC-DC LED driver. It has TRIAC dimming capability. It is basically a low side buck which has valley filled PFC. It takes an input voltage of 120V AC. This circuit uses LM3445 which is an adaptive constant off-time AC/DC buck (step-down) constant current controller designed to be (...)
Design files
REFERENCE DESIGNS Download
Forward converter with Universal input driving 2x6 LEDs
PMP7762 — PMP7762 is an offline LED driver with TRIAC dimming. It has short circuit protection as well as op amp control for dimming. It uses 2 op amp control for each LED string to ensure that current in the LED strings match. LM3445 includes a bleeder circuit to ensure proper triac operation by allowing (...)
Design files
REFERENCE DESIGNS Download
LM3445 – 220VAC, 7W Dimmable Isolated
PMP7751 — This demonstration board highlights the performance of a LM3445 based Flyback LED driver solution that can be used to power a single LED string consisting of 6 / 7 series connected LEDs from an 198 VRMS to 264 VRMS, 50 Hz input power supply. This is a two-layer board using the bottom and top layer (...)

CAD/CAE symbols

Package Pins Download
SOIC (D) 14 View options
VSSOP (DGS) 10 View options

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