公开(公告)号：EP1790075A1

公开(公告)日：2007-05-30

申请号：EP05774833.7

申请日：2005-08-18

申请人： Koninklijke Philips Electronics N.V.

发明人： TRAA, Boris, Philips IP & Standards ,  VAN DALFSEN, Age J., Philips IP & Standards

IPC分类号： H03H1/00 ,  H03H11/10

CPC分类号： H03H11/10 ,  H03H7/427 ,  H03H11/42

摘要： The invention relates to an Electromagnetic Interference (EMI) filter circuit (Fa) for suppressing a Line Conducted Interference (LCI) signal. The EMI filter circuit (Fa) comprises a filter inductance (Lo) to carry a supply current (Isup) between a supply voltage (Vsup) and a load (L). The EMI filter circuit (Fa) further comprises an active circuit (Ca), arranged in parallel with the filter inductance (Lo). The active circuit (Ca) comprises a sensing circuit (Mm) to sense the LCI signal and further comprises a suppressing circuit (Ms) to suppress the LCI signal. In an embodiment of the active EMI filter circuit (Fa), the active circuit (Ca) comprises a negative inductance generating circuit to create a negative inductance value. Selecting the negative inductance generating circuit to create an inductance value (Lca) larger than the inductance value of the filter inductance (Lo) creates a resulting inductance (Lr) which is higher compared to the inductance value of the filter inductance (Lo). In one embodiment, the negative inductance generating circuit comprises a negative impedance converter.