Everyone must be familiar with the term – Switched Mode Power Supply or SMPS. Yes, they are used in every personal computer. In fact, the Switched Mode Power Supply is widely used with many other devices. Once it is understood that what SMPS actually is, its countless applications can be easily imagined. An SMPS is used for converting the electronic power supply efficiently. Any SMPS has some storage components which store electrical energy to supply to the load device and some switching components which turn on and off at high frequencies charging and discharging the storage components.
A computer is an assembly of several essential and optional electronic parts such CD drive, motherboard, hard disk etc. Every peripheral has its own power requirement and to serve the same regulated power supplies such as linear power supplies, ferro resonant power supplies and switched mode power supplies, are used.Switched mode power supplies are unanimously preferred as computer power supply units for their small size and high efficiency. SMPS units dissipate less power by employing a transformer that regulates input voltage and provides constant current to the peripherals attached to the computer.
D.C. to D.C. converters and D.C. to A.C. Converters belong to the category of Switched Mode Power Supplies (SMPS). The various types of voltage regulators, used in Linear Power Supplies (LPS), fall in the category of dissipative regulator, as they have a voltage control element usually transistor or zener diode which dissipates power equal to the voltage difference between an unregulated input voltage and a fixed supply voltage multiplied by the current flowing through it. The switching regulator acts as a continuously variable power converter and hence its efficiency is negligibly affected by the voltage difference. Hence the switching regulator is also known as ‘non-dissipative regulator’. In a SMPS, the active device that provides regulation is always operated in cut-off or in saturation mode.