Runo's Power Design

SMPS is an abbreviation of Switch Mode Power Supply.
SMPS deals with techniques for conversion of electric energy from a arbitrary input voltage to one or several fixed output voltages. It works by chopping the current at high frequency, in some cases putting the chopped current through a transformer, and subsequently recovering the chopped energy in the new form. 

An SMPS involves at least two fast switches, e.g. mosfet transistors and diodes, together with capacitors and inductors and often also transformers. The transistors are turned on and off repeatedly at high frequency in a certain time pattern, controlled by a feedback loop, which enables us to control and stabilize the output voltage or current. 
In principle, the conversion in an SMPS takes place without loss of energy.

SMPS converters can be designed in a vast number of topologies, i.e. different ways to connect the above components together, in order to achieve desired properties. Some of the simplest are known as BUCK or BOOST converters, but a lot of other interesting topology groups exist, for instance resonance converters, a group of converters which is gaining increasing attention.

The advantage of converting energy at a high frequency is that the inductors, transformers, and capacitors involved can be small and lightweight.

A disadvantage is that an SMPS emits noise which can interfere with radio communication.

SMPS techniques have gained increasing popularity during the last 30 - 40 years for supply of nearly all sorts of electronic equipment.

home