US 5,731,666 A · Integrated-magnetic filter having a lossy shunt

Abstract

A two-winding, integrated-magnetic EMI filter provides damped common-mode and differential-mode inductances. The preferred embodiment of the filter has a magnetic core structure that incorporates a high-permeability C-core, a high-permeability I-core, and a low-permeability, lossy shunt. The three core pieces are assembled so as to form a structure that, similar to an E-I configuration, has two winding windows. The loss in the shunt aids in dissipating noise and it diminishes the effects of unwanted parasitic resonances by providing damping for the differential-mode inductance. Damping for the common-mode inductance is provided by losses in the C and I core pieces. Varying the reluctance of the shunt allows the differential-mode inductance to be adjusted separately from the common-mode inductance in order to tune the filter to remove desired noise frequencies. Another embodiment of the invention incorporates a high-permeability toroid core and a low-permeability, lossy shunt.

Claims6

Dependent claims

An integrated-magnetic assembly for a filter having improved damping comprising:

a C-core having an upper portion, a first leg and a second leg, the C-core having a permeability;
an I-core positioned adjacent to the first and the second legs to form a magnetic flux path between the first and second legs, the I-core having a permeability;
a shunt core having a permeability, the permeability of the shunt core being less than either the permeability of the I-core or the permeability of the C-core, the shunt core positioned between the C-core and the I-core;
a first winding encircling the I-core between the first leg and the shunt core;
a second winding encircling the I-core between the second leg and the shunt core;
a shunt magnetic path formed between the C-core and the I-core, the shunt magnetic path having at least one air gap, the shunt core having a reluctance, the air gap having a reluctance, the shunt magnetic path having a reluctance, the reluctance of the shunt magnetic path being a sum of the reluctance of the air gap and the reluctance of the shunt core, the reluctance of the shunt magnetic path primarily determined by the magnitude of the reluctance of the shunt core.

3 more elements

Dependencies are inferred from the claim text.

Integrated-magnetic filter having a lossy shunt

Life of this patent

Integrated-magnetic filter having a lossy shunt

Life of this patent

Abstract

Claims6