Is it possible to implement TRIAC dimming? Is there any reference schematic?

The only device that supports Triac Dimming is the HV9931. Our HV9931 solution works in a certain range and has restrictions. The primary restrictions of our recommended solution are:

  1. 120 VAC only
  2. Pulsed light output with 120 Hz cycle

Decent dimming performance for non 120 VAC applications is extremely hard to achieve (non 120 VAC as in 230 VAC or universal line range 85 VAC - 265 VAC). US dimmable bulbs generally dim over a small range or exhibit flicker on the low end. The problem is the small amplitude of the AC load current. Triac dimming controls require substantial load current for predictable behavior and this requirement is in direct contradiction with high efficiency LED lighting.

The problem manifests itself as a light flicker at low brightness settings. Some drivers may be better than others, but the flicker is almost unavoidable. Even our 120 VAC driver flickers when nominal LED power dips below a certain level. Our driver generates LED current, which is modulated at twice the line frequency, 120 Hz in the US.

It has been shown that this type of flicker creates headaches and fatigue after long exposure.

For more information, please read the HV9910B datasheet, which refers to PWM or LINEAR dimming.

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