The simulation results are shown in Fig. 5. Fig. 5(a) shows
that power loss in the MOSFET (sum of the switching and
conduction loss) increases with any increase in the ON-state
resistance, and Fig. 5(b) and (c) shows the output voltage and
duty cycle of the converter, respectively. The PI controller
maintains a fixed output voltage by changing the duty ratio to
compensate for any variation in RDS(ON). The failure rate of
the MOSFET increases with any increase in RDS(ON) due to
increased thermal stress and thereby increases the failure rate
of the converter as well. These are shown in Fig. 5(d) and
(e), respectively. It should be noted that increased RDS(ON)
in a closed-loop system do not increase the reliability of the
converter as opposed to the open-loop system discussed in [2].
The MTTF of the converter is reduced by about 2238 h (0.2556
years) for the variation in RDS(ON) from 34 to 44 mΩ, and this
is shown in Fig. 5(f)