  In this paper we propose a PI passivity-based controller, applicable to a
large class of switched power converters, that ensures global state regulation
to a desired equilibrium point. A solution to this problem was reported in
\cite{HERetal} but it requires full state-feedback, which makes it practically
unfeasible. To overcome this limitation we construct a state observer that is
implementable with measurements that are available in practical applications.
The observer reconstructs the state in finite-time, ensuring global convergence
of the PI. The excitation requirement for the observer is very weak and is
satisfied in normal operation of the converters. Simulation results illustrate
the excellent performance of the proposed PI.
