Electromagnetic interference isolator with common mode choke
First Claim
Patent Images
1. A common mode choke comprisinga first series connected transformer comprising a core, a primary winding and a secondary winding, said primary winding and said secondary winding being wound around the core;
- and,a second series connected transformer comprising a core, a primary winding and a secondary winding, said primary winding and said secondary winding being wound around the core,wherein, in use, with a respective load applied across an output of said primary winding and said secondary winding of each of said first transformer and said second transformer and an input of each of said secondary windings connected to a ground, said common mode choke appears as a substantially constant impedance to any differential mode component of signals applied to an input of said primary windings of said first transformer and said second transformer whilst attenuating any common mode component.
2 Assignments
0 Petitions
Accused Products
Abstract
A termination is provided for a differential transmission line such as unshielded twisted pair (UTP) to isolate a connected device from electromagnetic interference present on the UTP in the form of differential mode and common mode noise. An example of an electromagnetic interference isolator comprises a common mode and a differential mode termination, a common mode choke which exhibits substantially constant impedance over a wide bandwidth and a centre tapped isolation transformer.
137 Citations
9 Claims
-
1. A common mode choke comprising
a first series connected transformer comprising a core, a primary winding and a secondary winding, said primary winding and said secondary winding being wound around the core; - and,
a second series connected transformer comprising a core, a primary winding and a secondary winding, said primary winding and said secondary winding being wound around the core, wherein, in use, with a respective load applied across an output of said primary winding and said secondary winding of each of said first transformer and said second transformer and an input of each of said secondary windings connected to a ground, said common mode choke appears as a substantially constant impedance to any differential mode component of signals applied to an input of said primary windings of said first transformer and said second transformer whilst attenuating any common mode component. - View Dependent Claims (2, 3)
- and,
-
4. A termination for two or more differential transmission lines, each of said transmission lines having two signal paths, said termination having a common mode choke comprising:
-
a first series connected transformer comprising a core, a primary winding and a secondary winding, said primary winding and said secondary winding being wound around the core; and
,a second series connected transformer comprising a core, a primary winding and a secondary winding, said primary winding and said secondary winding being wound around the core, wherein, in use, with a respective load applied across an output of said primary winding and said secondary winding of each of said first transformer and said second transformer and an input of each of said secondary windings connected to a ground, said common mode choke appears as a substantially constant impedance to any differential mode component of signals applied to an input of said primary windings of said first transformer and said second transformer whilst attenuating an in-band common mode component. - View Dependent Claims (5, 6, 7, 8, 9)
-
Specification