Memory Page Buffer Sensing Node Precharge Voltage Sampling

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Solution Overview

Problem

Semiconductor memory devices face challenges in maintaining data integrity and sensing margin, particularly under low power conditions and varying trip voltages, which affect the read and write operations of nonvolatile memory devices.

Innovation Solution

The solution involves partially charging a sensing node in a page buffer to a precharge voltage, boosting it to a higher voltage, and transferring this voltage to a sensing latch to reflect the data stored in a memory cell, while compensating for variations in trip voltage by sampling and adjusting the precharge voltages based on the trip voltage of the latch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the sensing node is charged to a fixed precharge voltage, then the circuit operation is simple, but the sensing margin decreases due to trip voltage variations

Engineering Contradiction:

Improvecircuit operation complexityVSAvoidsensing margin

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent dynamically adjusts the precharge voltage level based on the sampled trip voltage. Instead of using a fixed precharge voltage, the system modifies the precharge voltage parameter to compensate for trip voltage variations, thereby maintaining an adequate sensing margin while adapting to different operating conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the trip voltage is sampled and used to adjust the precharge voltage. This closed-loop control ensures that the sensing node is charged to an appropriate voltage level that compensates for trip voltage variations, improving sensing reliability without requiring overly complex circuit operations.

Inventive Principle:

Principle #23Feedback

2Reliability

If the precharge voltage is increased to compensate for trip voltage variations, then the sensing margin is improved, but the risk of overcharging and data loss increases

Engineering Contradiction:

Improvesensing marginVSAvoiddata loss

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent samples the trip voltage before charging the sensing node to the precharge voltage. This preliminary measurement allows the system to determine the appropriate precharge voltage level in advance, preventing both undercharging (which would reduce sensing margin) and overcharging (which would cause data loss).

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the precharge voltage parameter based on the sampled trip voltage to achieve optimal sensing margin while preventing data loss. By changing the precharge voltage parameter adaptively rather than using a fixed high voltage, the system maintains reliability without risking information loss.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If additional voltage sampling and adjustment circuits are added, then the sensing margin is improved, but the device complexity increases

Engineering Contradiction:

Improvesensing marginVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the voltage sampling and adjustment circuits to serve multiple functions within the page buffer. The same circuitry is used for both sampling the trip voltage and adjusting the precharge voltage, reducing the need for separate dedicated components and minimizing the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses the existing sensing node and associated transistors as intermediaries to implement the trip voltage sampling and precharge voltage adjustment. By leveraging existing circuit elements rather than adding completely new components, the patent improves sensing margin while minimizing the increase in device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10290343B2Memory devices that sample latch trip voltages prior to reading data into latches and methods of operating same

Publication Date: 2019.05.14 SAMSUNG ELECTRONICS CO LTD

AI summary

Methods of operating a memory device include at least partially charging a sensing node within a page buffer of the memory device to a first precharge voltage, by sampling a trip voltage of a sensing latch within the page buffer. Thereafter, a voltage of the sensing node is boosted from the first precharge voltage to a higher second precharge voltage. Then, a voltage of the sensing node that reflects a value of data stored in a memory cell of the memory device is developed at the sensing node. The developed voltage is then transferred to the sensing latch so that data stored by the sensing latch reflects the value of data stored in the memory cell.