Patent ID: 6157248
Filing Date: 2000-12-05
Classification: H03H

Abstract:
An active filter circuit comprisingan input terminal of the active filter circuit for inputting an input signal;an output terminal of the active filter circuit for outputting an output signal;a first differential amplifier;a second differential amplifier;a third differential amplifier;a first capacitor; anda second capacitor,wherein an input terminal of the active filter circuit is connected to a non-inverting input terminal of the first differential amplifier,an output terminal of the first differential amplifier is connected to a non-inverting input terminal of the second differential amplifier wherein the first capacitor is connected between the connection of the output terminal of the first differential amplifier to the non-inverting input terminal of the second differential amplifier and ground,an output of the second differential amplifier is connected to a non-inverting input terminal of the first differential amplifier via the second capacitor, an inverting input terminal of the first differential amplifier, an inverting input terminal of the second differential amplifier, a non-inverting input terminal of the third differential amplifier, and output terminal of the third differential amplifier and the output terminal of the active filter circuit, andan inverting input terminal of the third differential amplifier is connected to ground.