Power Integrations introduced a new reference design (DER-281) detailing an 85%-efficient, 15 W PAR38 downlight driver that delivers flicker-free dimming without the use of unreliable high-voltage electrolytic bulk capacitors.

Typical TRIAC dimmers were designed for incandescent lights that use an order of magnitude more power than LED lights of equivalent lumen output. The low current requirement of LED lights, especially when dimmed, can cause TRIACs to switch off unexpectedly or oscillate, creating an annoying flickering effect. Early-generation LED lighting designs addressed this problem either by storing energy in an unreliable electrolytic bulk capacitor, adversely affecting bulb lifetime, or by allowing a continuous flow of current into the bulb, wasting energy and thereby defeating the main benefit of LED lighting. Single-stage LinkSwitch-PH ICs, combined with the innovative active damping and bleeding circuitry employed in DER-281, eliminate these pitfalls, providing flicker-free dimming with high efficiency and long lifetime.

The advanced, single-stage approach embodied in DER-281 meets every one of the LED designer’s checkboxes – it is highly efficient, accurate, and meets all PFC and harmonic content rules. It’s also long-lived and compatible with existing home dimmers.