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A linear continuous low frequency small signal model, valid for all types of converters (boost,buck, buck boost), both in heavy and light modes, is presen ted in this paper. Its interesting characteristics are that it is valid for free running as well as for fixed frequency converters and that it allows easily to take into account both input and output filters.Thanks to its modularity and its simple general form, it gives a strong insight into the influence of various parameters, (such as input filters) on perfor mance dynamics and into the design of efficient control loops.Finally, a computer program, using state analysis, has been developed allowing the automatic performance analysis of complete controlled converters. 1.With this in mind, it appeared to the authors that it should be interesting to dispose of a method gathe ring, on a practical point of view, the advantages of the state approach (namely its generality, the possibi lity to deal in the same way of all types of converters, in heavy and light modes, the easy description of a complex graph in which the cell is imbedded...) and those of the block diagram methods with their physical significance.The "injected current methods" seem in the author^ opinion to be a significant step towards this objective.In Section 2, the principles of the method will be briefly recalled and it will be shown how the method can take into account both input and output filters. The general model thus obtained gives new insight onthe way an input filter might destabilize a cell.In Section 3, some particularities of the model, as given in Section 2, will be discussed. Attention will be focused on the precautions which are to be taken when using it on simulation purposes in account of its non minimality. A minimal model will then be derived.In Section 4, it will be shown, using graph theory and state representation, how the previous results can be used for a fully automatic analysis of complete controlled converters.

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