APPLICATION NOTE
16
Figure 15: Efficiency Calculation
Step Load Change Response
VRMs may need to supply current to loads that are transient in nature. Such sudden loading or unloading
of VRM may pose an additional challenge for the VRM controller. Sudden transients can even trip the
VRM or its output may swing outside the specified range. Such situation necessitates the simulation of
VRM under transient load conditions. This is done by simulating step load change at the output of VRM
and variation in output voltage, and performance of feedback loop can be verified under various operating
conditions. In order to simulate step load response additional circuitry has been added to simulate
transient load. This additional circuit (refer figure 16) creates 33% step jump in load current and after
some time (5mSec) this additional load is disconnected. Load Step_Current_Responce display setting to
see the load current variation and its impact on output voltage.
