Switch Mode Power Supply (SMPS) Utilizing Flyback Converter Topology: Simulation and Experiment

Abstract

This paper presents simulation and experimental works of a single, 5 volt DC output switch mode power supply (SMPS). The main objective of this work is to design, build and evaluate the SMPS using flyback converter topology. In this work, a 555 timer was chosen as the pulse width modulator. The 555 timer was chosen because it is easily available, cheap and has the capability to produce stable pulse width modulation. The complete circuit of the SMPS consist of full bridge rectifier, smoothing capacitor, pulse width modulator, high frequency transformer and flyback converter. The complete SMPS circuit was firstly designed and simulated using Proteus software. After obtaining acceptable results from the simulation process, the hardware part of the project, soon follows. Next, the SMPS circuit was constructed on a breadbroad. Testing and measurements of important parameters such as the input and output voltages and duty cycle were carried out using digital oscilloscope and multi meter. Both simulation and experimental results have shown that the designed circuit can convert single 24 Vrms 50 Hz AC voltage input into a stable single 5±0.15 V DC outputs. This work also has shown that pulsed DC voltage with peak value of 3.8 V and frequency lower than 4 kHz is adequate in controlling the switching frequency of a MOSFET transistor, thus regulating the output voltage within the desired range. Further analysis also shows close correlation between the simulation and experimental results.