Created: May 03, 2016
The circuit shown is a simple design of a buck converter. Buck converter or step-down converter is primarily a DC-DC converter. It basically steps down voltage from its supply input whereas stepping up current to its output load. Well, you can also d
The circuit shown is a simple design of a buck converter. Buck converter or step-down converter is primarily a DC-DC converter. It basically steps down voltage from its supply input whereas stepping up current to its output load. Well, you can also derive your source from the AC main lines via rectifier.
This buck converter is designed to have an output voltage of 5V from its 10V input supply with 4A load current. The design consists of a transistor and an LCD circuit (also known as flywheel circuit). Transistor's main function is switching only, thus, controlling the current that flows to the load via the inductor. Knowing that the inductor stores energy, its action opposes changes in the current flow which prevents the switching transistor from increasing its peak value immediately. In the event that the switching transistor is in the "on" state, current flows to the load allowing the inductor to store its energy and capacitor to charge gradually but diode here is reversed biased. When the inductor reached its peak energy storage in the form of a magnetic field, it then releases its energy back into the circuit as a back electromotive force as the current from the transistor is switched off. When the transistor now is in the "off" state, the back electromotive force from the inductor causes back the current to flow around the circuit via the load and diode which now is now forward biased, the charge stored in the capacitor becomes the main source of current keeping it to flow through the load until the next "on" period begins.
Buck converter can be used as voltage regulator converter for high digital content ICs in graphic cards, netbook, desktop and note book PC. Also, in notebooks microprocessor power supplies, battery charger for notebook PC and even in advanced telecom and datacom systems.