The buck-boost converter consists of a transistor for switching purpose, diode, inductor, and capacitor. Buck-boost converter is the combination of the buck converter and boost converter and connected in cascade. Buck-boost converter is a converter whose output voltage is greater than or less than the input voltage. The output polarity the of the buck-boost converter is opposite of input polarity, due to this buck-boost converter is also known as inverting converter. There are two modes in buck-boost converter one is continuous mode and second is discontinuous mode. These modes depend on switching actions of transistors and the current flowing through the inductor. The buck-boost converter is similar to flyback converter but in the flyback converter, it uses the transformer and in the buck-boost converter, it uses a single inductor. Buck-boost converter is a DC to DC converter means its input is also DC and output is also DC. Buck-boost converter is a non-isolated type of converter. When the transistor or any switch is on the current in the inductor increases and the diode is in off condition and when the transistor or switch is off then the diode allows the flow of current.
The buck-boost converter is also known as chopper amplifier-converter. In buck-boost converter both input current and diode current are discontinuous.