Transition-mode dimmable LED driver for illumination applications

A transition-mode (TM) dimmable high brightness light-emitting-diode (LED) driver for general and residential illumination applications is presented. An improved pulse-width modulation dimming technique utilizing a low cost micro-controller is studied and implemented with a current-regulated LED drive. Under universal input voltage operation, high power factor and high efficiency can be achieved by a coupled inductor flyback converter, regulated by a TM power-factor-correction controller. The operation principles of the proposed LED driver will be discussed and evaluated. A laboratory prototype is also designed and tested for verification.