Electromagnetic interference shielding for small magnetic apparatus

Application Number  00128385 Application Date  2000.11.28
Publication Number  1298189 Publication Date  2001.06.06
Priority Information   1999/11/29 US 09/450,934  
Applicant(s) Name  Lucent Technologies Inc.  
Inventor(s) Name  Jao.L. Andress;Michael.R. Beyle  
Patent Agency Code  11038 Patent Agent  wang maohua
AbstractThe present invention provides magnetic structure, particularly an isolation transformer, which includes a shield to prevent radiation of electromagnetic interference (EMI). The magnetic structure includes a support structure, or bobbin, on which are mounted windings formed from electrical conductors. The windings are electrically connected to termination points, which provide the electrical interconnections for the magnetic structure. A magnetic core can be included in the support structure to provide optimal magnetic properties to the device. An EMI shield formed from a metallic foil such as copper is wrapped around the winding to prevent the radiation of EMI. The EMI shield is connected to a shield pin in the support structure by a conductive strap such that the shield pin is electrically connectable to a fixed potential through a safety rated capacitor to provide a low impedance path for currents induced in the EMI shield.