Better Do the Math Ignore Transfer Functions at Your Own Peril

Better Do the Math Ignore Transfer Functions at Your Own Peril 

It seems that there must be at least two distinct groups of people working in power. 

By presenting examples of interesting transfer function interactions, I am hoping to show that it does actually help significantly if engineers try to think in a relatively abstract manner, and it can translate into a better product, not just some yellowing seminar material fighting for immortality on a dusty shelf. 

The dc transfer function of a topology is simply the expression connecting the input and output voltages. Most engineers realize that it follows directly from the fact that we have a voltseconds law in existence, which must be diligently upheld by the concerned inductor of any viable topology. Viable implies that the topology (discovered or yet-to-be) can exist indefinitely in a steady and stable state. If not, we will certainly hear about it from the switch. 

Now consider the equation for the output of a buck-boost in discontinuous conduction mode ( DCM ) 

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