Second-Stage Buck LED Driver with Exceptional Deep Dimming Performance for Commercial Lighting Applications

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Deep Dimming with Virtually No Flicker Even Down to 1%

The iW3638 second-stage buck LED driver provides constant current to LEDs directly from DC power supplies. It supports a non-isolated buck converter topology to post-regulate from an off-line AC/DC converter, minimizing low frequency output ripple current and eliminating virtually all flicker in the system, even down to 1%.

A wide range of DC input voltages simplifies design by enabling the use of just one second-stage driver across any commercial lighting product portfolio.


  • Single-Stage DC/DC Buck
  • Supports Wide DC Input Voltage with Tight Output Current Regulation (±3%)
  • Output Power up to 90W
  • PrimAccurate™ Primary-Side Control for Excellent Output Current Regulation with No Direct Voltage and Current Feedback Components Needed
  • Independent Maximum Load Current Setting Interface
  • PWM Dimming
  • Supports 0-10V Dimming with iW339 Dimming Interface
  • Wide Dimming Range: 1% - 100%, with 1% Resolution
  • Configurable Minimum Dimming Setting
    • Dim-to-Off, 1%, 5%, or 10%


  • Fully Protected
    • Output Over-Voltage, Output Open, Output Short, Over-Current, Peak Current Limit, Sense-Resistor Short Protections
    • Input Voltage Under-Voltage Protection
    • Built-In Over-Temperature Protection or External NTC
    • Brown-In and Brown-Out Protection
  • Small SOIC 8-Lead Package


  • Commercial Lighting:
    • T8
    • 0-10V Dimming
    • External Fixture Drivers
    • Wireless and Intelligent LED Lighting Systems

Block Diagrams

Functional Block Diagram
Typical Applications Diagram


Product Briefs and Summaries

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