Differential Chopper Comparator With Kickback Noise Compensation

Solution Overview

Problem

Comparators in analog-to-digital converters generate kickback noise due to capacitive coupling, which degrades system performance, causes signal errors, and hinders operating speed.

Innovation Solution

A differential chopper comparator with input terminal, chopper circuits, comparison, and compensation circuits to amplify and offset input signals, effectively removing kickback noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a comparator is used to compare sample points with reference voltages, then digital code generation is achieved, but kickback noise is generated that degrades system performance

Engineering Contradiction:

Improvedigital code generationVSAvoidkickback noise

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary compensation circuit between the comparator and the input signal source. This compensation circuit includes a compensation capacitor and compensation transistor that generate a compensating signal to counteract the kickback noise before it propagates back to the input terminal, thus eliminating the harmful effect while maintaining the comparator's digital code generation function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the output signal from the comparator is fed back through a feedback network including a feedback capacitor and feedback transistor. This feedback signal is used to generate a compensating signal that is injected back into the input terminal to cancel the kickback noise, creating a closed-loop system that actively suppresses the harmful effect

Inventive Principle:

Principle #23Feedback

2Measurement precision

If kickback noise is present in the comparator, then signal errors occur and settling time increases, but the comparator structure remains simple

Engineering Contradiction:

Improvesignal accuracyVSAvoidcomparator structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary compensation circuit between the comparator and the input signal source. This compensation circuit includes a compensation capacitor and compensation transistor that generate a compensating signal to counteract the kickback noise before it propagates back to the input terminal, thus eliminating the harmful effect while maintaining the comparator's digital code generation function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrical parameters of the comparator circuit by introducing adjustable compensation capacitors and transistors with controllable gain. These parameter changes allow the compensation circuit to dynamically adjust its compensating effect to match the kickback noise characteristics, improving signal accuracy without requiring a complete redesign of the comparator structure

Inventive Principle:

Principle #35Parameter changes

3Speed

If kickback noise is generated by capacitive coupling, then operating speed is hindered, but the comparator design is conventional

Engineering Contradiction:

Improveoperating speedVSAvoidcapacitive coupling noise

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary compensation circuit between the comparator and the input signal source. This compensation circuit includes a compensation capacitor and compensation transistor that generate a compensating signal to counteract the kickback noise before it propagates back to the input terminal, thus eliminating the harmful effect while maintaining the comparator's digital code generation function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary action by proactively generating the compensating signal before the kickback noise can significantly degrade the signal quality or slow down the operating speed. The compensation circuit is designed to anticipate and counteract the noise generation mechanism, allowing the comparator to operate at higher speeds without the detrimental effects of capacitive coupling noise

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12470206B2Differential chopper comparator capable of removing kickback noise

Publication Date: 2025.11.11 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed is a differential chopper comparator, which includes an input terminal circuit that receives a first input signal and a second input signal and selectively switches the first and second input signals to intermediate circuit, at least one chopper circuit that generates a first amplified signal and a second amplified signal by amplifying a difference between the first and second input signals at the intermediate circuit points, a comparison circuit that compares the first amplified signal with the second amplified signal, digitizes the comparison result, and outputs a digital signal at a logic level, and a compensation circuit that offsets the first amplified signal and the second amplified signal and thereby removes kickback noise induced in the input terminal circuit. The differential chopper comparator of the present disclosure may shorten the settling time and may operate at high speed.