Patent ID: 6489913
Filing Date: 2002-12-03
Classification: H03M

Abstract:
An improved sub-ranging analog-to-digital (ADC) converter of the type having a first converter stage with an analog signal to be converted as an input, a difference amplifier with an analog version of the output from the first converter stage and the analog signal to be converted as inputs, a second converter stage with the output from the difference amplifier as an input, and a digital correction circuit with the outputs from the two converter stages as inputs to produce as an output a converted digital signal corresponding to the analog signal to be converted wherein the first converter stage comprises:a sigma delta modulator having as an input the analog signal to be converted and having as an output a one-bit signal, the output being one of the inputs to the digital correction circuit; and a first analog filter having as an input the one-bit signal and having an output coupled as the analog version for input to the difference amplifier.