Input Buffer Offset Adjustment for Accurate Inversion Point Detection

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Solution Overview

Problem

Reduced voltage amplitudes in semiconductor memory devices cause variations in offset voltages (Voff) of input buffers, leading to undesired errors in determining the inversion point, which are not effectively addressed by existing technologies.

Innovation Solution

An offset voltage adjustment circuit is implemented, utilizing a test input buffer and a main input buffer with switches to adjust the offset voltage (Voff) by coupling the input pad to either the main or test input buffer and the reference voltage, allowing for precise adjustment of Voff through control flags, eliminating the need for a switch between the input pad and main input buffer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If reduced voltage amplitudes are provided to reduce power consumption, then power consumption is reduced, but offset voltage variations cause undesired errors in determining the inversion point

Engineering Contradiction:

Improvepower consumptionVSAvoidinversion point determination accuracy

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The patent adjusts the reference voltage parameter dynamically to compensate for offset voltage variations. By changing the reference voltage level based on detected offset conditions, the system maintains accurate inversion point determination even when operating at reduced voltage amplitudes for lower power consumption.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback mechanism where the offset voltage is detected and measured, then this information is used to adjust the reference voltage accordingly. This closed-loop feedback ensures that inversion point determination remains accurate despite operating at reduced voltages that minimize power consumption.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If a switch is added between the input pad and main input buffer to enable offset adjustment, then offset voltage can be adjusted, but device complexity increases

Engineering Contradiction:

Improveoffset voltage adjustabilityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the offset adjustment functionality with the existing input buffer circuit by directly coupling the reference voltage generator to the main input buffer. This integration eliminates the need for separate switches and additional control logic, achieving offset adjustability without significantly increasing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reference voltage generator is designed to serve multiple functions: it provides the reference voltage for inversion point determination and simultaneously enables offset voltage adjustment. This multi-functionality allows the system to adapt to different offset conditions without adding dedicated adjustment circuitry.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP3516655B1Apparatus of offset voltage adjustment in input buffer

Publication Date: 2026.01.28 MICRON TECHNOLOGY INC

Figure 1A~1B
Figure 2
Figure 3A

AI summary

Apparatuses for providing external terminals of a semiconductor device are described. An example apparatus includes an input pad, an input buffer including a first input node and a second input node, a switch that couples the first input node and the second input node in an active state and further decouples the first input node and the second input node in an inactive state, a control circuit that provides a signal causing the switch to be in the active state or an inactive state. The first input node of the input buffer is coupled to the input pad by a conductive wiring.