So first off, I will explain why we use switching regulators over other types of regulators, one of the major causes of the inefficiency of a linear regulator is that the pass transistor operates in the linear region. Meaning that it will constantly see both a high current and a high voltage or at the very least a moderate one. This ends up resulting in a large amount of power dissipation.
This is where the switching regulators come into play, switching regulators rely on the efficiency of the transistor switch. When the transistor is turned off or (not in saturation), there is no current flow, so therefore no power is being dissipated. Now when the transistor is turned on (in saturation), a high current will flow, but the voltage across the transistor, which is your Vce(sat), is quite small.
This is where you get the largest amount of dissipation from a switching regulator. The switching interval is the only time that the current or voltage is quite large. And due to the speed of switching this period is very short compared to the overall cycle time.
However, even though switching back on and off can be very efficient, this normally results in pulses that are not appropriate for most loads. To help smooth this out we can use and arrange inductors and capacitors. This is pertinent in the use of a switching regulator.
Above is a basic switching regulator. The signal coming out of the control element is a pulse train, unlike a linear regulator. It is then passed to the LC filter network to smooth out the pulses.
Now the heart of the circuit is actually in the pulse width modulator, this is where they duty cycle comes in to give the type of pulse waveform, depending on what the system requires.
Although there are many advantages to the switching regulator it does have its disadvantages as well. First off it is more complex than the basic linear regulators. This can be detrimental when looking at your low-power designs specifically. This circuit can also cause a noisy electrical noise when operating. In turn, if certain precautions such as shielding are not introduced will cause major interference to the nearby surrounding circuits.
Shown below are two other types of switching regulators:
The Buck Switching Regulator:
Boost Switching Regulator:
The Buck-Boost Switching Regulator:
Fiore, James. (May 22, 2022) Switching Regulators. LibreTexts Engineering. https://eng.libretexts.org/Bookshelves/Electrical_Engineering/Electronics/Operational_Amplifiers_and_Linear_Integrated_Circuits_-_Theory_and_Application_(Fiore)/08:_Voltage_Regulation/8.04:_Switching_Regulators
Electronics Tutorials. Switch Mode Power Supply. https://www.electronics-tutorials.ws/power/switch-mode-power-supply.html