Continuous-time delta-sigma modulator

Abstract

A continuous-time delta-sigma modulator includes a loop filter, a quantizer, a finite impulse response (FIR) filter, and a digital to analog converter. The loop filter integrates a difference between an input signal and a feedback signal. The quantizer quantizes a signal output from the loop filter to convert the quantized signal into a digital signal. The FIR filter performs an FIR filtering process on the digital signal output from the quantizer. The digital to analog converter converts a signal output from the FIR filter into an analog signal and outputs the converted analog signal as a feedback signal.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the priority of Korean Patent Application No. 10-2018-0068451, filed on Jun. 14, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.BACKGROUNDField[0002]The present disclosure relates to a continuous-time delta-sigma modulator.Description of the Related Art[0003]A delta-sigma modulator is implemented by a discrete-time manner or a continuous-time manner. A delta-sigma modulator according to the discrete-time manner stores or transmits an input signal to a capacitor in the form of charges, based on a switched capacitor technique. The discrete-time delta-sigma modulator operates for the input signal in accordance with a sampling process, but a continuous-time delta-sigma modulator may operate for the input signal without performing a sampling process.[0004]As compared with the discrete-time manner, according to the continuous-time manner, a design requirement...

AI Technical Summary

Benefits of technology

The invention provides a continuous-time delta-sigma modulator that can remove an aliasing error caused by a parasitic capacitor generated in a chopper circuit. The modulator includes a chopper circuit that removes low frequency noise from the Gm-C integrator, and a loop filter that includes a transconductor Gm and capacitors. Additionally, an FIR filter is used to increase the input range and remove the aliasing error. This invention allows for improved signal quality and reduced noise in the modulation process.

Problems solved by technology

In the case of a loop filter using a Gm-C integrator, due to a characteristic of an open loop, an input node of an amplifier is not caught as a virtual ground, so that it is difficult to obtain a broad input voltage range and a good linearity.

This may limit an input range and the linearity of the continuous-time delta-sigma modulator.

Images