LED lighting has been facing the constant challenge of dimming, and digital dimmers are particularly problematic. Power is an issue, for example. With digital technology the MPU needs approximately 20mA of power even when dimmers are turned off. Driver compatibility challenges also arise based on the level of legacy products they attempt to be compatible with.

The solution to dimming will be multi-faceted. One, for example, is to simplify and reduce the number of components, where possible, providing a more straight-forward solution while reducing cost.

In this vein, Diodes recently launched single-stage dimmable LED controllers, the AL1663 and AL1663R, designed to support fly-back and buck-boost topologies and provide accurate constant-current output while eliminating optocouplers and secondary control circuitry.

The single-stage dimmable LED controllers provide a cost-effective driver solution featuring:

  • Operation up to 150W
  • Multiple dimming options
  • High efficiency
  • Low EMI
  • Operation in boundary-conduction mode with valley switching control maintaining high power-factors and low total harmonic distortion.
  • Primary-side regulation (PSR) controller
  • Low total BOM component count and cost

Both versions, the AL1663 and AL1663R combine low start-up current and low operating current with the integration of such multiple protection features as over-voltage, short-circuit, over-current, and over-temperature.

The devices support PWM dimming and analogue dimming. The AL1663, for example, provides an additional dimming input pin capable of accepting a high-frequency signal and for PWM-to-DC conversion, while the AL1663R’s single dimming pin accepts analogue signals between 0.3 and 2.4V DC or a digital PWM input when connected with a suitable input capacitor. Both are housed in SO-8 packages.

Targeting such applications as general-purpose constant current source, LED backlighting driver, smart LED lighting, and general LED lighting driver with dimming function, the controllers are available now.