Patent ID: 6194959
Filing Date: 2001-02-27
Classification: H03F,H03H

Abstract:
An active filter circuit comprising:a first current amplifier comprising a first MIS transistor circuit arrangement, the first current amplifier including a first input terminal, a first output terminal, and at least one first control terminal configured to control a first current amplifier transconductance;a first capacitor connected at one first capacitor electrode to the first input terminal of the first current amplifier;a second current amplifier comprising a second MIS transistor circuit arrangement, the second current amplifier including a second input terminal, a second output terminal, and at least one second control terminal configured to control a second current amplifier transconductance, the second input terminal connected to the first output terminal of the first current amplifier, and the second output terminal connected by a DC conductor to the first input terminal of the first current amplifier; anda second capacitor connected at one second capacitor electrode to a node between the first output terminal and the second input terminal;wherein, when an input signal is input to the other terminal of the first capacitor, an output signal corresponding to the input signal filtered through a band-pass filter is obtained from the first output terminal of the first current amplifier and an output signal corresponding to the input signal filtered through a high-pass filter is obtained from the second output terminal of the second current amplifier.