In applications like regulated DC power supplies the input voltage might fluctuate but the output voltage is kept constant by adjusting the duty cycle ratio accordingly. In this applet the buck converter has a controller that automatically adjusts the duty cycle to keep the output voltage constant. The switching frequency, load level and input voltage all affect the duty cycle and whether the converter is operating in continuous or discontinuous conduction mode.

• Change the red time line to examine discontinuous current conduction mode.
• Adjust the input voltage and observe the change in the duty cycle.
• What impact do switching frequency and output resistance have on the conduction mode?