A power converter including a power switch, an output filter, and a controller. The output filter receives a switched input voltage and produces a filtered power converter output characteristic represented by a state vector. A controller coupled to the power switch and the output filter estimates the state vector of the output filter and controls the power switch by partitioning a state-vector plane into a first region and a second region employing a line passing through a desired output characteristic. The controller turns the power switch on when the estimated state vector lies in the first region and off when it lies in the second region. The steady-state switching frequency of the power converter is controlled by offsetting a state-vector component at a desired switching frequency. To estimate the state vector of the output filter, the controller may advantageously be coupled to the switched input voltage.