All You Need To Know About Working Principles And Usage Of Fly-Back Converter And Forward Converter!

ByAvinash Mittal

When the power supply is included with the switching regulator to convert electrical power from one form to another with specific features, it is called switch-mode power supply (SMPS). This power supply is used to get regulated DC output voltage from DC input voltage.

Here are some working principles of some common type of SMPS:

Fly-back Converter SMPS Working

Any SMPS circuit with a very low output power of less than 100W is defined as a fly-back converter SMPS. Such SMPS types have a very low and straightforward circuit compared to other SMPS circuits, and their usage is restricted to low power applications. The unregulated input voltage with a constant magnitude is changed into a defined output voltage by switching fast through a MOSFET; with a frequency, rate switching around 100 kHz. The voltage isolation can be achieved using a transformer.

A fly-back transformer has distinct features when compared to standard transformers. This type of transformers has two windings which act like a coupled magnetic inductor. The output is delivered through a diode and capacitor to filter and rectify.

Forward Converter type SMPS Working

Such type of SMPS is quite similar to fly back converter type SMPS. But, in a forward converter, a control is connected at the output of secondary winding to control switch. As compared to the flyback converter, the filtering and rectification circuit is complicated.

Such SMPS is also called DC-DC buck converter, with a transformer used for scaling and isolation. In addition to the diode and capacitor, an inductor and a diode are connected at the end of the output channel. If the switch gets on, then the input is given to the transformer’s primary winding. This is the reason why a scaled voltage is produced at the transformer’s secondary winding.

Such a Switch Mode Power Supply (SMPS) is regularly used for various switching applications with a power ranging within 100 W to 200 W.

There are other types of switch-mode power supply converters, and some common types are Buck-boost converter Self Oscillating fly-back converter, Buck converter, Boost converter, Cuk, Sepic, Boost-buck. A few other types of SMPS are AC-DC converter, DC-DC converter, Forward and Fly-back converter. It is always better to have a clear idea of the primary working model before going for an in-depth study about any of them.