Light-Emitting Commutating Diodes for Optical Wireless Communications Within LED Drivers

Abstract

Although visible light communication (VLC) systems provide high density links for use in Internet-of-Things (IoT) devices, the design of high rate VLC transmitters that maintain luminaire efficacy is an open problem. In this article, a novel approach to the integration of VLC within light-emitting diode (LED) drivers is proposed through the replacement of freewheeling/blocking diodes with light-emitting devices termed a light-emitting commutating diodes (LECDs). In this manner, communications and illumination can be provided using a simple, cost effective design while employing no additional components. The subtle change of LED driver control signals facilitates the transmission of data from LECDs while simultaneously supporting illumination functions. Lighting controls such as dimming are maintained and combined with modulation through the use of overlapping pulse position modulation (OPPM) and performance is quantified. Prototype buck and boost converters with LECDs are implemented and their efficacy is measured. Though current commercial LEDs are not intended for such signalling applications, we experimentally demonstrate their feasibility in this application and suggest methods to make such converters reliable. It is demonstrated that the addition of an LECD improves the efficacy of the luminaire as compared to conventional LED drivers while simultaneously enabling a VLC downlink.

CaO:Tb³⁺ green-emitting phosphor for white light-emitted diode-phosphor applications: the improvement of light output intensity

“…The study performs the simulations of three phosphor packages, consisting of in-cup phosphor, conformal phosphor, and two-layered remote phosphor. The Mie-scattering theory is applied to validate the phosphor layers' diffusing [16]- [18]. The study demonstrates that this CaO:Tb 3+ phosphor considerably promotes the illuminating beam and hue homogeneity of all three pc-WLEDs.…”

The role of indium composition in InxGa1−xN prestrained layer towards optical characteristics of EBL free GaN/InGaN nanowire LEDs for enhanced luminescence

“…1,2 Various works on LEDs have been reported, such as InGaN LEDs used in an optical link, 3 parallel flip-chip AlGaN LED whose electrical and optical characteristics display strong size dependence for communication in the UV range, 4 and introduction of light-emitting commutating diodes (LECDs). 5 III-nitride materials are capable of manufacturing lasers and LEDs, 6,7 but it is still difficult to get high efficiency GaN/InGaN LED. The strong piezoelectric polarization (PZ), along the c-plane direction, induced by high lattice mismatch within GaN and InGaN layers causes the quantum-confined Stark effect (QCSE) 8 which eventually causes reduction of device's efficiency (EQE).…”

“…In the UV wavelength range, LEDs are used in a broad range of applications, such as water purification, sterilization, chemical and bio‐chemical sensing, smart sensor networks, advanced manufacturing, and many more 1,2 . Various works on LEDs have been reported, such as InGaN LEDs used in an optical link, 3 parallel flip‐chip AlGaN LED whose electrical and optical characteristics display strong size dependence for communication in the UV range, 4 and introduction of light‐emitting commutating diodes (LECDs) 5 . III‐nitride materials are capable of manufacturing lasers and LEDs, 6,7 but it is still difficult to get high efficiency GaN/InGaN LED.…”

Discrete State-Feedback Control Design with D-Stability and Genetic Algorithm for LED Driver Using a Buck Converter

“…is phenomenon causes the current to have a great increment in its value when the voltage has small variations [1][2][3][4][5][6][7][8][9][10][11].…”