Patent ID: 8497731
Filing Date: 2013-07-30
Classification: H03H

Abstract:
1. A low pass filter circuit, comprising: an amplifier having a single-ended output; a first line and a second line arranged to receive a differential signal; a first switch for selectively connecting the first line to a first input of the amplifier in a first cycle of operation having a first observation window; a second switch for selectively connecting the second line to a second input of the amplifier in a second cycle of operation having a second observation window, wherein the first and second observation windows are at least partially coincident; a first resistor connected in series between the first line and the first switch; a first reference voltage supply connected to a first node between the first resistor and the first switch; a second resistor connected between the first reference voltage supply and the first node; a first capacitor, wherein a first terminal thereof is connected to a second node between the first switch and the first input of the amplifier; a third resistor connected in series between the second line and the second switch; and a second capacitor connected in a feedback path between the amplifier output and the second input of the amplifier, and wherein the low pass filter circuit is arranged for one of the first switch and the second switch to connect selectively the first reference voltage supply to a respective one of the first and second inputs of the amplifier and for the one of the first switch and the second switch to connect selectively a second reference voltage supply to the respective one of the first and second inputs of the amplifier.