Switched Capacitor Sampling Circuit for Stable Reference Voltage

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Solution Overview

Problem

Switched capacitor circuits face challenges in maintaining a predictable level of reference voltage, leading to variability in linearity and accuracy of operations, especially when dealing with differential inputs, which affects the overall performance and stability of electronic circuits.

Innovation Solution

The implementation of a switched capacitor circuit configuration that includes main and replica sampler circuits, along with an amplifier, where the main sampler circuit stores charges based on a reference voltage and the replica sampler circuit holds charges using a different reference voltage, ensuring a balanced supply of charges regardless of input levels, thereby maintaining a predictable reference voltage level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single reference voltage is used for both main sampler circuits, then the circuit structure is simple, but the amount of charge change in reference voltage varies with input level, affecting linearity and accuracy

Engineering Contradiction:

Improvelinearity and accuracyVSAvoidcircuit structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The reference voltage supply is segmented into two separate reference voltages (first reference voltage and second reference voltage) instead of using a single reference voltage. This segmentation allows independent control of charge supply to each main sampler circuit, ensuring that the amount of charge change in reference voltage remains even regardless of input level, thereby improving linearity and accuracy

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A replica sampler circuit is introduced as a copy of the main sampler circuit to model and control the charge supply. The replica sampler circuit receives the same input as the main sampler circuit and generates a replica output that reflects the charge change in reference voltage. This copying mechanism enables precise control and balancing of charge supply to maintain even charge change across different input levels

Inventive Principle:

Principle #26Copying

2Reliability

If reference voltage level varies with input level, then the circuit adapts to different inputs, but the electrical state fluctuation affects operation stability

Engineering Contradiction:

Improveoperation stabilityVSAvoidinput adaptation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The replica sampler circuit provides feedback information about the charge change in reference voltage to the control logic. By monitoring the replica output and comparing it with the actual input conditions, the system can adjust the reference voltages to maintain stable electrical states while adapting to different input levels. This feedback mechanism ensures operation stability without sacrificing adaptability

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If more charge supply circuits are added to maintain even reference voltage, then linearity improves, but circuit area and power consumption increase

Engineering Contradiction:

ImprovelinearityVSAvoidcircuit area

Core Design Contradiction:

Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The replica sampler circuit serves multiple functions: it models the charge supply behavior, provides feedback information, and enables control logic to adjust reference voltages. This multi-functionality allows the system to achieve even charge change and improved linearity without adding multiple separate charge supply circuits, thereby minimizing circuit area while maintaining high precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the linearity and accuracy of the switched capacitor circuit operations, reduces power consumption, and allows for faster operation speeds while being implemented on a small circuit area at a low cost.

Implementation Method 1

a first capacitive element for storing charges corresponding to one input of a differential input

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10476449B2Switched capacitor circuit to make amount of change in reference voltage even regardless of input level

Publication Date: 2019.11.12 SAMSUNG ELECTRONICS CO LTD

AI summary

A switched capacitor circuit includes a first main sampler circuit, a second main sampler circuit, a first replica sampler circuit, and a second replica sampler circuit. The first main sampler circuit samples a first input of a differential input, and generates a first output corresponding to the sampled first input based on a first reference voltage. The second main sampler circuit samples a second input of the differential input, and generates a second output corresponding to the sampled second input based on a second reference voltage. The first replica sampler circuit receives the first input, and holds the received first input based on the second reference voltage. The second replica sampler circuit receives the second input, and holds the received second input based on the first reference voltage.