A fully-integrated compact LED module with inductor-less and capacitor-less LED driver

Abstract

As LED chip and package continue to improve the luminous efficiency and reliability, the power supply driver starts to play a more important role in a high quality LED lighting system. The conventional LED driver using electrolytic capacitors as the energy storage element has relatively short lifetime, affecting the reliability of the entire LED lighting system. These drivers also contain many components that need to be surface mounted or soldered to a separate PCB which are large in size. This takes physical space in the lighting system, limits the design flexibility such as thermal management and optic design, and adds cost. Much effort has been given to develop high reliability, compact, low cost LED drivers in the recent years in order to accelerate the fast adoption of LED in broader lighting market. A novel LED Light Engine (Disclight™) that integrates a high voltage MOSFET based driver IC with multi LED chip arrays on a single substrate is presented in this paper. Leveraging its innovative control algorithm design and advanced IC technology, this integrated module is capable of connecting to either 110V or a 220V AC power line directly, and can drive the LED array without requiring any additional electronic components such as AC/DC convertor, inductors and electrolyte capacitors. The compact LED module significantly improves the reliability, reduces system cost, and cuts down the physical size of the module by more than 70 percent. These factors make it an excellent choice for indoor lighting applications ranging from 3–20W, such as candle lights, MR16, GU10 lamps and A-lamps. In this paper, we will discuss the working principle of this driver, the LED array structures including both COB and SMD array package, and the electro-optical characteristics of the modules. We will demonstrate an applications of C35 lamp and A60 light bulb with Disclight™ light engine inside and show module testing data that features a high power factor of 0.99 and low THD of <20%, high total lumen efficiency (including driver and LED) of 100m/W at warm white and CRI greater than 80. The LED light engine is also dimmable and is compatible with majority of existing Triac dimmer circuits. In addition, the module complies with EMI and other safety requirements.