Flickerless™ 25W Dual-Channel Solid-State Lighting LED Driver for Color Corrected, Sunset Dimming Applications

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Sunset dimming LED driver

The iW3640 is a highly integrated LED driver for off-line, sunset dimming solid state lighting applications up to 25W. With a dual driver output, the iW3640 allows for additional amber LEDs to be used in parallel with the main white LEDs, providing LED color mixing to create a dimming profile that accurately recreates the warmth of incandescent dimming all in a single controller IC. By integrating the secondary driver and using the digital engine to control the transitions, the iW3640 removes the cost of an external MCU and its dedicated power supply and provides an easy-to-use solution.

With Flickerless™ technology integrated, the iW3640 allows for full 1%-100%, flicker-free phase-cut dimming while working with most dimmer types, including leading-edge, trailing-edge and digital dimmers. The device is fully featured and with its two-stage approach, offers a powerful combination of high power factor (>0.95), low THD (<15%) and low ripple voltage (<20%).

The iW3640 is fully protected, including a built-in over-temperature protection derating feature that monitors an external NTC device and scales back the output LED current at high temperatures, permitting reliable and predictable operating life for LED luminaires. For more information on the OTP derating function, click here.


  • 2-channel, Sunset Dimming SSL LED Driver: 25W Output Power
  • Low BOM Cost – no MCU or Its Dedicated Power Supply
  • PrimAccurate™ Isolated Off-Line Controller
    • Eliminates Secondary-Side Regulator and Optical Feedback Isolator
  • LED Over-Temperature Derating
  • High Power Factor (PF) > 0.95, Low Total Harmonic Distortion (THD) < 15%
  • Phase-cut Dimming with Wide Dimmer Compatibility, Automatic Detection of Dimmer Type


  • Wide Dimming Range: 1% to 100%
  • Meets Global Energy Standards, Including European Union IEC61000-3-2
  • NEMA SSL 6 Compliant
  • Zhaga Hot-Plug Compliant
  • Fully Protected from Fault Conditions
    • LED Open-Circuit and Short-Circuit Protection
    • Over-Temperature Protection
    • Input Over-Voltage and Frequency
    • Sense-Resistor Short Circuit Protection


  • 25W Dimmable Solid State Lighting Retrofit Lamps
  • Warm Lighting/Sunset Lighting Dimmable Luminaires and LED Ballasts

Block Diagrams

Typical Applications Diagram
Functional Block Diagram


Product Briefs and Summaries

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