DC/DC-Converter Basic Topologies


Buck-Boost Converter

To open and close the switch of the buck-boost converter click on the power switch.

The left-hand applet shows the time behavior of the switch gate signal, and of characteristic currents and voltages of the buck-boost converter. Drag the vertical (red) time-marker line with the mouse. The according switching states are shown in the animated circuit in the right-hand top applet. The (orange) gate-signal cannot be dragged with the mouse because the duty cycle is set by the output voltage controller.

Normalized current: i= Iout,avg/(U2/(2*L*f))

The right-hand applet shows a diagram of the duty cycle in dependency of the normalized load. To change the constant voltage ratio drag the (red) curve with the mouse. Change the actual load by dragging the red point with the mouse. The green line defines the borderline between continuous and discontinuous inductor current mode.
Remark: Here the output voltage is kept constant by the output voltage controller. Therefore, changing the voltage transfer ratio u2/u1 does change the input voltage.