Patent ID: 7683704
Filing Date: 2010-03-23
Classification: H03H

Abstract:
1. A balanced low pass filter comprising: a first coil coupled between a first input and a first output terminal of said filter; a second coil coupled between a second input and a second output terminal of said filter; a capacitor coupled between said first and said second output terminals; a current sense circuit having first inputs coupled across a first impedance coupled between said first input terminal and said first coil, second inputs coupled across a second impedance coupled between said second input terminal and said second coil, and an amplifier having an input coupled to an output of said current sense circuit and having an output connected to a ground terminal via third and fourth coils forming part of a filter enhancement means, said third coil being magnetically coupled to said first coil, said fourth coil being magnetically coupled to said second coil, said first, second, third and fourth coils being located on a same core of a transformer, wherein said amplifier includes a cascade coupling of a frequency dependent amplifier and a transconductance amplifier configured to translate an output voltage of said frequency dependent amplifier into a corresponding current.