Photalume AC LED light engine technology is unique, using US patents 9,723,671, 9,585,212 and 9,491,821. Previous generations of AC LED light engines used integrated circuit control chips, which limited the power possible. These older conventional AC LED circuits were typically limited to about 30W, unless several were mounted on one PCB in which case the component count was doubled or more. Photalume technology light engines can be made as powerful as is desired, using the same basic circuit. Described below is a nominally 4000 lumen light engine which runs at approximately 40W. Furthermore the light output from Photalume light engines is modulated using a band of frequencies around 360Hz, which is higher than the highest frequency which the human eye can perceive. (200 Hz). The 4000 lumen light engine described below is currently the most powerful single array flat AC LED light engine to be constructed. Furthermore it has a lower flicker index (0.21) by far than legacy AC LED light engines (0.34). In reality the difference is even greater because the flicker index metric is not frequency sensitive. A flicker metric which takes into account frequency is the CFD index developed by DerLichtpeter in Germany. Older legacy light engines have a CFD metric of 53%, while the 4000 lumen Photalume light engine has a CFD index of 23.5%, a factor of two lower because of the frequency response of the human eye. Some competing AC LED light engines achieve low flicker index using banks of bulky, short lived electrolytic capacitors. By contrast all the capacitors in a Photalume light engine are long lived ceramic capacitors which make the lifetime of the product limited only by the lifetime of the LEDs. Although a 4000 lumen light engine is described below, the same basic technology could be used to make a 10,000 lumen street light. An important consideration is the fact that since legacy AC LED light engine technologies have to double the component count to achieve power levels above 30W (or more for higher power levels) then Photalume technology is the lowest cost way to make light engines of above 30W and simultaneously has flicker performance which is 1.5X better than legacy technologies.
The circuit of the 4000 lumen light engine
4000 lumen light engine
The Bill of material for this product and a licence to use this technology can be obtained by contacting firstname.lastname@example.org. It can be laid out as a circular disk, a square or in a linear configurtion. At 10,000 piece distributor pricing, the BOM cost including the PCB and connector is about $16.00.
THE PERFORMANCE OF THE 3000 LUMEN LIGHT ENGINE.
Below is a picture showing a scope shot of the input current (top) and the output iight profile (bottom).
The horizontal time scale is 4 msecs per division. It can be seen that the AC line current at the top approximates to a sinusoidal waveform, which provides good power factor and THD. The frequencies present in the light output waveform are on the order of 360 Hz, which is much higher than the highest frequency which the human eye can resolve. Below is a tabulation of the main performance parameters.