Reduced Power Read Sensing for OTP Memories

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Solution Overview

Problem

One-time programmable (OTP) memory cells with low resistance states consume significant power during sensing operations, posing a challenge in low-power systems such as battery-powered devices or those with limited power sources.

Innovation Solution

A sensing circuit with multiple bias circuits and a differential sense amplifier is used to equilibrate and limit current through OTP memory cells, reducing power dissipation by providing mirrored reference currents and controlling the program and read word lines, allowing for low-power data sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional sensing means are used for OTP memory cells with low resistance states, then data can be read, but power consumption becomes high

Engineering Contradiction:

Improvedata sensing capabilityVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

A current limiting circuit is introduced as an intermediary component between the memory cell and the sensing circuit. This mediator restricts the maximum current that can flow through the memory cell during sensing operations, thereby limiting power consumption while still allowing the sensing circuit to detect the resistance state of the memory cell

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensing circuit parameters are optimized to operate effectively with current-limited memory cells. By adjusting sensing thresholds and timing parameters, the circuit maintains accurate data detection capability despite the reduced current available due to the current limiting circuit

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If oxide breakdown is used for memory programming, then memory can be programmed, but low resistance states result in high power consumption during sensing

Engineering Contradiction:

Improveprogramming capabilityVSAvoidsensing power consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The current limiting circuit serves as a mediator that decouples the programming mechanism (oxide breakdown creating low resistance) from the sensing operation power consumption. It allows the memory to maintain its programmed state while restricting power during subsequent read operations

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If low resistance memory cells are used, then programming is achieved, but power dissipation during sensing increases significantly

Engineering Contradiction:

Improvememory state storageVSAvoidpower dissipation

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The current limiting circuit acts as an energy loss mitigation intermediary, allowing the low resistance state to be maintained for reliable data storage while preventing excessive power dissipation during sensing by capping the maximum current flow

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensing operation parameters are modified to be compatible with current-limited conditions, ensuring that data can be reliably detected from memory cells with controlled current flow, thus maintaining reliability while reducing energy loss

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20170025186A1Reduced Power Read Sensing for One-Time Programmable Memories

Publication Date: 2017.01.26 SYNOPSYS INC

AI summary

A low power consuming read circuit for a memory array is disclosed. The circuit is particularly useful in applications where oxide breakdown one-time programmable memory is integrated into a system having low power available from the power sources supplying the system.