Application of novel D²T control to single-switch two-output switching power converters

A novel method for programming current in dc/dc converters operating in discontinuous conduction mode is described in this paper. The control variable is the product of the square of the duty cyle and the switching period, i.e., D2T, which is directly proportional to input and output currents of a discontinuous-mode converter. A method of controlling D2T is applied to converters that utilize one switch (or one set of synchronous switches) for achieving two control functions. In particular a single-switch two-output boost converter, in which a continuous-mode converter and a discontinuous-mode converter share one active switch, is studied. In this system, current-mode control is used to regulate the output voltage of the continuous-mode converter and the proposed D2T control is used to regulate the other discontinuous-mode converter. The result is a generic current-mode controlled two-output converter.