Switched Mode Power Supply Topologies

The way power is transferred in an SMPS is determined by its circuit configuration, also called topology. It means, the efficiency of a switching mode power supply is mostly due to the topology of its circuit. The standard efficiency of linear power supplies is 30% but it can be as high as 80% in an SMPS device.

Losses during conversion of power does not benefit the system in any way. In fact, it imposes an additional burden on the user as well as the system. It was this quest for efficiency that led the transition from linear power supply to the switching mode power supply.

There are over 10 billion power supplies working worldwide. About 3.5 billion of these are located in the US itself. Of them, custom power supplies constitute a meager number, though they offer a number of advantages over both linear power supplies and SMPS.

These common power supplies use about 110 to 150 billion kWt hrs of energy, with a loss of about 3-4%. So more and more people are turning to switching mode power supplies and where feasible, custom power supplies, to power electrical devices.

In SMPS units, some power gets wasted during rise and fall times. In that small window, the switching transistor enters a linear operating area. Nevertheless, embedded engineers have lauded SMPS units for their efficiency, leading to their enhanced adoption in industry.