Understanding SMPS

As all we know that,SMPS is one of the important part of any computer system and after that only very few people know about it.An SMPS(Switched Mode Power Supply) is an electronic power unit that is used as a switching regulator.The main task of any SMPS is to switch the power supply between the saturation (full on) and cutoff (completely off) with a variable duty cycle whose average is the desired output voltage.After this the resulting rectangular waveform that is formed passed through a combination of a capacitor and inductor.The main advantage of this method is greater efficiency because the switching transistor dissipates little power in the saturated state and the off state compared to the semi conducting state (active region).In addition to these advantages,SMPS is light in weight and in smaller size so that it can easily fit into your pc.On the other hand it also have some disadvantages like greater complexity, the generation of high amplitude, high frequency energy that the low-pass filter must block to avoid EMI and a ripple voltage at the switching frequency and the harmonic frequencies thereof.

SMPS can be classified into four types according to the input and output waveforms, as follows.

AC in, DC out: rectifier, off-line converter input stage.
DC in, DC out: voltage converter, or current converter, or DC to DC converter
AC in, AC out: frequency changer, cycloconverter
DC in, AC out: inverter
AC and DC are abbreviations for alternating current and direct current.