Constant-frequency clamped-mode resonant converters

Two clamped-mode resonant converters are proposed which operate at a constant frequency while retaining the desired features of conventional series- and parallel-resonant converters. State-plane analyses are performed which identify all possible circuit-operating modes of a clamped-mode series-resonant converter and define their mode boundaries. The control-to-output characteristics are derived to specify design regions for both natural and forced commutations. A breadboarded circuit was built to demonstrate the feasibility of the constant-frequency clamped-mode operation. All the predicted operating modes were verified experimentally.<>