Technologies have specific life cycles, driven by internal innovation, subsequently reaching maturity. Power electronics appears to be a much more complex case as an enabling technology spanning an enormous range of powers, functions and applications. Power electronics is also divided into many constituent technologies. Up to the present, the development of power electronics has been driven chiefly by internal semiconductor technology and converter circuit technology, approaching maturity in its internally set metrics (ex. efficiency). The fundamental functions found in electronic energy processing, the constituent technologies comprising power electronics and the power electronics technology space are examined critically in the light of the internal driving philosophy of power electronics and its historical development. It is finally concluded that, although approaching the limits of its internal metrics indicate internal maturity, the external constituent technologies of packaging, physical impact and converter control technology still present remarkable opportunities for development. As an enabling technology, these developments, together with internal developments such as wide band-gap semiconductors, will be driven externally by applications in future.