Input Buffer Voltage Generation Circuit for Stable Reference Levels

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Solution Overview

Problem

Semiconductor circuits face challenges in maintaining stable output characteristics due to variations in supply voltages, particularly between external and internal supply voltages.

Innovation Solution

A voltage generation circuit and input buffer configuration that includes diode-connected transistors and a compensation circuit to generate reference voltages, which are insensitive to variations in internal supply voltage levels, ensuring stable output signals regardless of supply voltage fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the internal supply voltage level rises, then the threshold voltage of the second transistor rises, but the second reference voltage level varies significantly

Engineering Contradiction:

Improvesecond reference voltage level stabilityVSAvoidoutput characteristic stability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The voltage generation circuit uses feedback through the third transistor configured to operate according to a first reference voltage. The third transistor adjusts the second reference voltage based on the first reference voltage, creating a feedback mechanism that compensates for threshold voltage variations of the second transistor, thereby stabilizing the second reference voltage level despite internal supply voltage changes.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The circuit changes the operating parameters by using the first reference voltage (generated from external supply voltage) to control the third transistor, which in turn adjusts the second reference voltage. This parameter change approach allows the circuit to compensate for threshold voltage variations and maintain stable output characteristics regardless of internal supply voltage fluctuations.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If diode-connected transistors are used to generate reference voltages, then the circuit complexity is reduced, but the output characteristic stability under supply voltage variations deteriorates

Engineering Contradiction:

Improvevoltage generation circuit complexityVSAvoidoutput characteristic stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The voltage generation circuit achieves multi-functionality by using a combination of diode-connected transistors (first and second transistors) for simple voltage generation and a controlled transistor (third transistor) for stabilization. This universal approach allows the circuit to perform both simple voltage generation and stable reference voltage maintenance, achieving output characteristic stability without excessive complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11550347B2Voltage generation circuit and input buffer including the voltage generation circuit

Publication Date: 2023.01.10 SK HYNIX INC

AI summary

A voltage generation circuit may include: a first transistor coupled to an internal supply voltage terminal, and configured as a diode-connected transistor; a second transistor coupled to the first transistor and configured as a diode-connected transistor; and a third transistor coupled between the second transistor and a ground voltage terminal, and configured to operate according to a first reference voltage generated based on an external supply voltage. The voltage generation circuit may limit a variation in level of a second reference voltage which is generated through a drain terminal of the second transistor as a threshold voltage of the second transistor rises according to a rise in level of the internal supply voltage.