The mode of operation of boost converter is based on two
states; ON state and OFF state. It is also known as charging
mode instead of ON state, and discharging mode instead of
OFF state. During the charging mode; when the switch is
closed, the diode is in reversed-biased condition. When the
switch is open that is discharging mode, the inductor current
cannot change instantaneously, thus the diode becomes
forward-biased in order to provide a path for inductor
current. A current generator IZ is added in parallel with the
load resistor to facilitate in examining the response of the
converter to the load changes.