Landsman based PFC with PWM dimming for high brightness LED driver

Abstract

This paper presents a Landsman converter fed power factor correction (PFC) based light emitting diode (LED) driver. The application is targeted for high brightness (HB) projection application with brightness control of high brightness red-green-blue (HB-RGB) LED. A pulse width modulation (PWM) technique is used for current control to achieve effective brightness required without compromising the efficiency (overall 85%). This PFC converter is used to feed a dual output flyback DC-DC converter which supplies power to the forced cooling unit and the LED module with galvanic isolation. The brightness control of LED is performed by synchronous buck converter via current modulation. The PFC converter is designed to operate in discontinuous input inductor current mode for inherent PFC at universal AC mains. A prototype of the proposed PFC LED driver is developed and experimentally verified. The power quality parameters of the proposed LED driver are evaluated at rated and light load conditions for universal AC mains (90-265V) with brightness control. The power quality parameters are found within acceptable range of international harmonic standard IEC 61000-3-2 for universal AC mains.