Attention Makers


Light engine with low cost and high light quality

MAKERS: Peter COUNTRY: United States

Conventional AC light engines give out light with 120 Hz modulation which causes headaches. This new light engine modulates the light at 350 Hz, which nobody can see.

The Purpose

Light engines are circuit cards which connect directly to the power line and use LEDs to light up. They are inexpensive and easy to install in light fixtures. Existing products have a powerful light modulation at 120 Hz which gives some people headaches. This new invention has 2X less modulation and moves it up to a frequency of 350 Hz which nobody can see. The circuit which does this draws power from the line with a power factor greater than 0.9. It can be used for downlights, street lights and warehouse lights with lower cost and better light quality.

The Technology

The invention uses a new circuit principle which has not been previously described. Using only capacitors, diodes and resistors (plus a 2 transistor switch) it draws power from the power line with power factor greater than 0.9 and puts out light with a flicker index of 0.15. This had previously been thought to be impossible. The circuit only uses small ceramic capacitors, and has an electrical efficiency of 85%. Details of the circuit operation are in US patent application 20160100464. The novel circuit principle can only work if it has already been working, and thus takes several cycles to stabilize.

Additional Details

This new circuit concept is applicable to decorative lights, down lights, exterior building lights, parking lot lights and street lights, all with lower cost and better light quality than existing solutions. Existing AC light engines have notoriously poor light quality (flicker index of 0.34) and are limited in size to about 30W by the power capability of an IC control chip. The new circuit (the Photalume light engine) can be scaled up from 5W to 500W using the same circuit topology. It can be dimmed down to 3% using a trailing edge dimmer.

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