Power supply design

Abstract

Most of the devices in laboratories are electrically powered and need a stable source of power supply to function. A power supply transforms the incoming alternating current (AC) source to a suitable steady output of direct current (DC) supply. In addition, a power supply must produce the correct electrical quantities of voltage, current, and frequency. The user must determine the correct specification required for use, as failure to do so may cause damage to the devices and pose a threat to lives. There are three types of power supplies: linear, switch mode, and unregulated power supply. Our focus will be on the linear and switch-mode power supplies commonly used in laboratories. Both power supplies produce DC supply. However, they differ in terms of the process of producing the output. Linear power supplies have fixed voltages for a spectrum of input voltages. Any extra incoming voltages are eliminated to produce a maximum output voltage to the connected load. The switching power supply works like the linear power supply, with an integrated switching transformer. Choosing which type to use depends on the user’s application, efficiency requirements, and budget. In past investigations, it was found that linear power supply needs more significant semiconductor parts to control the output supply and hence produces additional heat, making it less efficient due to the considerable difference in input and output voltages. On the other hand, SMPS has a wide output range and generates lower heat, although it has high ripple output and electromagnetic interference as it switches in high frequencies. The project aims to produce a power supply that best fits and is applicable for the desired usage and address the issues accordingly. A deliverable of a regulated DC bench power supply with an adjustable output of up to 30V, 3 Amperes is detailed in this report.