Analog Counter Reduces Circuit Area in Semiconductor Storage

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Solution Overview

Problem

The existing semiconductor storage devices using ΔΣmodulation require large circuit areas for digital counters to read multi-level data, leading to increased chip size and noise between bit lines, which complicates data reading and increases the need for complex address allocation.

Innovation Solution

The implementation of an analog counter within the sense amp, utilizing ΔΣmodulation, reduces the circuit area and allows for simultaneous reading from multiple bit lines, thereby reducing noise and simplifying data reading by averaging the bit line potential through charge accumulation and voltage sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a digital counter is used to read multi-level data in a sense amp using ΔΣmodulation, then data reading capability is improved, but the circuit area becomes enormous

Engineering Contradiction:

Improvedata reading capabilityVSAvoidcircuit area of the counter

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent replaces the digital counter system with an analog integration system. Instead of using a digital counter to count quantized values, the invention uses an analog integrator to accumulate the modulated current signal directly, converting the digital counting process into an analog integration process. This substitution dramatically reduces the circuit area while maintaining the ability to read multi-level data.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters from digital domain to analog domain. By using an analog integrator with a capacitor to accumulate charge proportional to the modulated current, the system operates in the analog domain throughout the sensing process, eliminating the need for digital counting circuits and their associated large area requirements.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If the memory cell holds multi-level data, then data storage capacity is improved, but the circuit area of the digital counter becomes enormous

Engineering Contradiction:

Improvedata storage capacityVSAvoidcircuit area of the digital counter

Core Design Contradiction:

Quantity of substanceVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If simultaneous reading from multiple bit lines is implemented, then data retrieval speed is improved, but noise between bit lines increases

Engineering Contradiction:

Improvedata retrieval speedVSAvoidnoise between bit lines

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the sense amp circuit into multiple independent analog integrator units, with each integrator dedicated to a specific bit line. This segmentation allows simultaneous operation of multiple integrators without mutual interference, as each integrator processes its bit line signal independently through separate capacitor-based accumulation circuits.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces capacitor-based analog integrators as intermediary elements between the bit lines and the data output. These integrators act as mediators that accumulate and average the current signals over time, effectively filtering out high-frequency noise and interference while preserving the data information.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach minimizes the chip area required for data reading, reduces noise between bit lines, and enables faster data retrieval from all bit lines simultaneously, improving the accuracy and efficiency of data sensing.

Implementation Method 1

an accumulation unit which accumulates an amount of charge in accordance with a potential of the bit line

Methodology Applied

Scientific EffectCharge accumulation: Capacitance

Data Source

PatentUS8542521B2Semiconductor storage device including memory cells capable of holding data

Publication Date: 2013.09.24 KIOXIA CORP

AI summary

According to one embodiment, a semiconductor storage device includes first cells, first bit and first word, and first sense. The first cells are capable of holding 2-level or higher-level data. The first bit and first word are capable of selecting the first cells. The first sense detects a first current. The first sense includes a first supply unit, a first accumulation unit, a detector, and a counter. The first supply unit supplies a second current when the data is read. The first accumulation unit accumulates an amount of charge. The detector detects the potential the amount of charge. The counter counts output from the detector. The counter includes a second supply unit, a second accumulation unit, and a sensing unit. The second supply unit charges a first node. The second accumulation unit accumulates a charge. The sensing unit detects the amount of charge of the second accumulation unit.