Multilevel Command And Address Signaling for Compact Memory Dies

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Solution Overview

Problem

The increasing demand for faster and more capable semiconductor memories leads to a need for more memory control information, which often requires additional external terminals, increasing semiconductor memory die size and circuit complexity.

Innovation Solution

Implementing multilevel command and address signals to convey commands and addresses, allowing for the same number of external terminals to represent a larger number of commands and addresses, or maintaining the same number of terminals while expanding the command and address space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If additional external terminals are added to provide more command and address signals, then the memory control information capacity increases, but the semiconductor memory die size and circuit complexity increase

Engineering Contradiction:

Improvememory control information capacityVSAvoidcircuit complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The patent changes the voltage parameter of the command and address signals to have multiple distinct voltage levels (e.g., first voltage level for first set of commands, second voltage level for second set of commands). This allows the same physical terminal to convey more information by varying the voltage parameter, thereby increasing memory control information capacity without adding external terminals or increasing circuit complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent makes the existing command and address terminals multi-functional by enabling them to represent multiple different commands and addresses through multilevel voltage signaling. Instead of requiring dedicated terminals for each command/address, the same terminals serve multiple functions by encoding different values through different voltage levels, thus increasing information capacity without increasing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Loss of information

If additional external terminals are added to provide more command and address signals, then the memory control information capacity increases, but the semiconductor memory die size increases

Engineering Contradiction:

Improvememory control information capacityVSAvoidsemiconductor memory die size

Core Design Contradiction:

Loss of informationVSArea of stationary object

Solution Approach 1:

The patent utilizes multiple voltage levels on existing terminals to encode additional command and address information. By changing the voltage parameter from binary to multilevel, the information capacity per terminal increases without requiring additional terminal pins, thus preventing die size expansion while improving memory control information capacity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adds a voltage level dimension to the command and address signaling. Instead of using more terminals in the spatial dimension, the invention exploits the voltage level dimension to encode additional information, allowing the same physical terminal to represent multiple commands and addresses through different voltage levels, thereby increasing capacity without increasing die size

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the number of commands and memory addresses increases, then the memory performance and capability improve, but the number of external terminals required increases

Engineering Contradiction:

Improvememory capabilityVSAvoidnumber of external terminals

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent changes the signaling parameter from binary voltage levels to multilevel voltage levels on existing terminals. This allows each terminal to represent multiple different commands and memory addresses by varying the voltage level, thereby supporting increased memory capability and command diversity without increasing the quantity of external terminals

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent enables existing external terminals to serve multiple functions by implementing multilevel voltage encoding. Each terminal can represent multiple different commands and addresses through different voltage levels, making the terminal system more versatile and adaptable to increased memory capabilities without requiring additional terminals

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12462853B2Apparatuses and methods including multilevel command and address signals

Publication Date: 2025.11.04 LODESTAR LICENSING GROUP LLC

AI summary

Multilevel command and address (CA) signals are used to provide commands and memory addresses from a controller to a memory system. Using multilevel signals CA signals may allow for using fewer signals compared to binary signals to represent a same number of commands and/or address space, or using a same number of multilevel CA signals to represent a larger number of commands and/or address space. A number of external command/address terminals may be reduced without reducing a set of commands and/or address space. Alternatively, a number of external terminals may be maintained, but provide for an expanded set of commands and/or address space.