Patent ID: 7606051

Claim:
A fully clamped coupled inductor power conversion circuit formed by applying an improvement method to a unclamped coupled inductor power conversion circuit, wherein said unclamped coupled inductor power conversion circuit has at least two operating states, and wherein said unclamped coupled inductor power conversion circuit comprises at least a first coupled inductor having at least a first winding and a second winding, an inductance connected in series with said first coupled inductor, and a first switch means, wherein at least one of said windings of said first coupled inductor is unclamped in at least one of said operating states of said unclamped coupled inductor power conversion circuit, said improvement method comprising the following steps, Step (1): adding an active clamp network such that said active clamp network is coupled to said unclamped winding of said first coupled inductor, said active clamp network comprising, second switch means, wherein said second switch means are placed in a conducting state during said operating state of said unclamped coupled inductor power conversion circuit in which said unclamped winding of said first coupled inductor was unclamped and wherein said second switch means are placed in a non-conducting state during all other operating states, and a capacitor coupled to said unclamped winding of said first coupled inductor through said second switch means during said operating state of said unclamped coupled inductor power conversion circuit in which said unclamped winding of said first coupled inductor was unclamped, Step (2): repeating step (1) for each of said windings and each of said operating states of said unclamped coupled inductor power conversion circuit until all of said windings of said coupled inductor are clamped during all of said operating states, whereby said fully clamped coupled inductor power conversion circuit becomes fully clamped by application of said improvement method to said unclamped coupled inductor power conversion circuit thereby eliminating ringing and over shoot associated with said inductance.