Molecular electronics seeks to decrease the cost, power consumption and size of devices, using a variety of approaches. However, few attempts have been made to address circuit simulation. The availability of common semiconductor components means they can be used for modeling and simulating molecular circuits to speed progress in molecular electronics. The present study examines the switching of a gated oligo-phenylenevinylene (OPV) molecule as a NMOS molecular transistor, resistance as an indicator of methyl molecules, and the linking of these abilities using LTspice simulation software. The circuit simulation of molecules of basic logic gates, half-adder, full-adder, and multiplier logic circuits are carried out. The numerical results may shed light on the next applications of molecular systems and make them a good, promising candidate for field-effect transistors.

Designing and Modeling of Logic Circuits Based on Switching of the Gated Oligo-Phenylenevinylene Molecule

A novel flyback light emitting diode (LED) driver with adaptive switching frequency for smart lighting is proposed in this investigation. Switching loss and severe harmonic distortion of conventional flyback LED drivers when the LED is operating in high switching frequency and high voltage are resolved. The proposed flyback LED driver design auto-adjusts the switching frequency by detecting the conduction period and the current of LED. Adaptive switching frequency approach is then applied to enhance efficiency and maintain the color and brightness.

A flyback driver with adaptive switching frequency control for smart lighting1

Currently, the use of Light Emitting Diodes (LED) bulbs has been intensively increasing since LED possess various qualifications of high efficiency in light production, not radiating heat, no toxic substance, lifespan longer than other bulbs. However, when the circuit of LED Driver is connected directly to high power LED with an AC source, it causes high losses of energy and the occurrence of the non-sinusoidal waveforms thus causing the harmonic series in the power supply system. In the research, a circuit for driving high power LED at high power of 30 watts was created by using a Fly-Back converter converting AC into DC current. At the same time, IC LinkSwitch-PH model LNK418EG was applied to act as a factor correction for electric power and control the constant output currents and electromotive force. After the input AC current at 180-240 volts was applied on the experimental circuit, the input current which has the waveform close to a sine shape resulted in the low distortion of the input current but provided the constant output current and electromotive force. LED’s high luminance could be detected at ​​300 luxs at a distance of one meter and its performance was 90 percentages.

Development of High Power LED Driver Using LNK418EG

This paper is an investigation into the high inrush current effect that emerges during the energizing of drivers of different circuit types loaded by light-emitting-diode (LED) strips. Two different driver circuit types were analyzed—a voltage stabilization (VS) circuit utilizing a Zener diode, and a current stabilization (CS) circuit type in the form of an integrated circuit (IC). Inrush current waveforms were calculated for drivers loaded by various numbers of LEDs. In the frame of the study, analysis executed for drivers energized by diverse input voltage RMS values at different switching-on phases was performed. The analysis is comprised of experimental verification of LT SPICE simulation results of current waveforms and calculations of current peak values appearing while switching on the supply voltage. The developed models for simulation needs were elaborated concerning precise reflection of the real current and voltage waveforms obtained during oscilloscopic registration of the switching-on process. The assumed simulation model parameters were mainly attuned in view of steady-state current simulations, and the implemented method of high-frequency (HF) transient modeling allowed for precise current waveform reflection. Finally, the utilization effectiveness of the proposed simple inrush current limiting circuit was estimated.

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Modeling of Inrush Current Surges—LED Strip Drivers Case Study

LED technology has been used widely in various applications due to its advantage in term of functionality, high efficiency, low cost, small size and high reliability. In order to improve LED performance and prolong LED's life, High Power LED driver is been developed. LED driver is used to control output voltage by using current mode controlled method. This development of LED driver can increase the LED operation efficiency, provide high voltage protection, decreases the driver size and lastly make possible of user friendly installation. Voltage source is step up by using boost converter as main circuit. In control circuit, current mode controlled is used to regulate output characteristic of High Power LED. LTC 3783 is used as PWM controller to drive the gate and provide pulse signal to the MOSFET. This driver is designed to operate load that consists of 6 units LED each rating of 5 Watt connected in series. Theoretical calculation is made to obtain component specification. The LTspice software is used to simulate the driver circuit by using calculated parameters before move on to hardware implementation. Eagle software is used to design the Printed Circuit Board (PCB). Then, all components are mounted on the PCB which is made of FR4 material. The hardware built is tested experimentally and the output waveform is recorded.

/pdf/development-of-high-power-led-driver-using-ltspice-software-2vf1ss7s6y.pdf

Mohamad Fakhrudin Sulaiman Mustahim

Papers

Development of High Power LED driver using LTspice software