AC Direct LED Driver Enables High-Performance, Low-Cost Phase-Cut Dimming

The iW3989 AC direct LED driver from Dialog Semiconductor offers a high-performance, low BOM cost approach for phase-cut dimming SSL LED driver applications by integrating a high-voltage MOSFET and eliminating the need for magnetics, an RC damper and an external bleeder.

Designed for downlights and replacement bulbs such as GU10, PAR, A19 and BR types, the device can operate with virtually all dimmer types including leading-edge, trailing-edge and smart dimmers, while providing very fast dimmer transient response.

The iW3989 achieves efficiency similar to a switch-mode converter without utilizing magnetics for energy storage, which addresses the thermal challenges of SSL lighting without adding unnecessary cost.

Applications are expected to include SSL Replacement Bulbs (GU10, AR19, BR, PAR), Downlights, etc.

And by removing the magnetic component, there is no audible noise when interfacing with a TRIAC dimmer, providing a noise-free, flicker-free and robust solution that approaches the feel of an incandescent lighting experience.

Typical application. (click on schematic to enlarge)

Summary of features:

  • 15W Output Power
  • AC Direct LED Driver – No Magnetics
  • Integrated High Voltage MOSFET
  • Good Phase-Cut Dimmer Compatibility
    • Leading-Edge
    • Trailing-Edge
    • Smart Dimmers
  • Flicker-free and No Audible Noise
  • Wide Dimming Range: 1% – 100%, with 1% Resolution
  • Fully Protected
    • LED Open-Circuit and Short-Circuit
    • Current Setting Resistor Short Circuit
    • Over-Temperature Derating
    • Thermal Shutdown
  • Small, QFN Package

Functional block diagram (click on image to enlarge).

(click on table to enlarge)

Dialog Semiconductor plc
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