Patent ID: 6285311
Filing Date: 2001-09-04
Classification: H03M

Abstract:
An apparatus including a switched capacitor filter circuit having reduced offsets and allowing for offset compensation without a closed feedback loop, comprising:a chopper stabilized amplified filter circuit that receives one or more chop control signals, receives and low pass filters an input data signal and provides a low pass filtered signal with an out of band signal frequency component which is at a frequency of said one or more chop control signals and represents an offset and 1/f noise of said chopper stabilized amplified filter circuit;an output filter circuit, coupled to said chopper stabilized amplified filter circuit, that receives and filters said low pass filtered signal and provides a filtered output data signal in which said out of band signal frequency component is substantially reduced in magnitude; andan analog-to-digital conversion (ADC) circuit, coupled to said output filter circuit, that receives and converts said filtered output data signal and provides a digital output signal;wherein as a result of said providing of said low pass filtered signal and said filtered output data signal by said chopper stabilized amplified filter circuit and said output filter circuit, respectively, said digital output signal includes a residual offset within one least significant bit (LSB) of a value of said digital output signal.