US 12,294,346 B2
Electromagnetic interference filter having controlled impedance magnitude
Alessandro Amaducci, Deitingen (CH); and Enrico Mazzola, Gerlafingen (CH)
Assigned to Schaffner EMV AG, Luterbach (CH)
Filed by Schaffner EMV AG, Luterbach (CH)
Filed on Feb. 11, 2022, as Appl. No. 17/670,311.
Claims priority of application No. 21157900 (EP), filed on Feb. 18, 2021.
Prior Publication US 2022/0263486 A1, Aug. 18, 2022
Int. Cl. H03H 7/06 (2006.01); H03H 1/00 (2006.01); H03H 7/01 (2006.01)
CPC H03H 7/06 (2013.01) [H03H 7/0115 (2013.01); H03H 1/0007 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An electromagnetic interference (EMI) filter for suppressing interferences in a DC network, the network comprising:
a source device powering a load device via a bus connectable to the source device at an input side and to the load device at an output side;
the EMI filter being connected to the bus and comprising an active filter circuit having an active filter bandwidth and being configured to sense a noise component superimposed in the bus at the input side traveling towards the output side and inject a cancelling noise in the bus to suppress said noise component;
wherein the EMI filter further comprises a passive circuit including a passive source circuit connected to the bus at the input side and a passive load circuit connected to the bus at the output side, the passive circuit being configured to provide, at each frequency of the active filter bandwidth, a source impedance at the input side that differs from a load impedance at the output side by a factor of at least two.