Input rectification: This process takes the AC mains voltage and converts it into a DC rectified wave using a diode bridge. A capacitor is added at the output of the bridge to reduce the ripple voltage.

Power factor correction (PFC): Because of the nonlinear current in the rectifier, the harmonic content of the current is quite large. There are two ways two resolve this. The first is passive PFC, using a filter to dampen the effect of the harmonics, but it is not very efficient. The second option, called active PFC, uses a switching boost converter to make the current waveform follow the input voltage shape. Active PFC is the only method of designing a power converter that meets current standards of size and efficiency.

Isolation: Switching power supplies can be isolated or non-isolated. A device is isolated when the power supply’s input and output are not physically connected. Isolation is done through the use of transformers, which galvanically isolate the two halves of the circuit. However, transformers can only transfer electric power when there is a variation in current, so the rectified DC voltage is chopped up into a high-frequency square wave, which is then transferred to the secondary circuit, where it is rectified again and finally transmitted to the output.

There are many different aspects to consider when designing a switching power supply, especially related to safety, performance, size, weight, etc. The control circuits for switching power supplies are also more complex than in linear power supplies, which is why many designers find it useful to implement integrated modules in their power supplies.