Non-Volatile Memory Driver Biasing for High-Temperature Stability

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Solution Overview

Problem

Existing driving circuits for non-volatile memory fail to stably provide driving signals at high temperatures, leading to increased leakage current and operational issues due to transistors operating beyond safe voltage differences, which affects the normal operation of the non-volatile cell array.

Innovation Solution

The driving circuit design incorporates a specific configuration of transistors and biasing circuits to maintain transistors within a safe operation area by managing voltage differences and using multiple supply voltages, ensuring that nodes are not in a floating state, thereby preventing excessive leakage current and maintaining stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the driving circuit operates at high temperature, then the leakage current increases, but the circuit cannot provide stable driving signals

Engineering Contradiction:
Improveoperating temperatureVSAvoidsignal stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent applies parameter changes by using multiple supply voltages (first supply voltage VDD1, second supply voltage VDD2, third supply voltage VDD3) to dynamically adjust the operating parameters of transistors. The biasing circuits adjust the gate-source voltage and gate-drain voltage of transistors based on temperature conditions, changing the electrical parameters to keep transistors within the safe operation area and reduce leakage current at high temperatures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements beforehand cushioning by using biasing circuits that proactively adjust the voltage levels of transistors before they enter the unsafe operation region. The first biasing circuit connected to the gate terminal of the first transistor and the second biasing circuit connected to the gate terminal of the second transistor预先 adjust the gate voltages to prevent excessive voltage differences that would cause transistors to operate beyond safe limits, thus cushioning against the harmful effects of high temperature before they occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If transistors operate beyond safe voltage differences, then leakage current increases, but normal operation is maintained

Engineering Contradiction:
Improveoperation continuityVSAvoidleakage current
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent employs feedback mechanisms through the biasing circuits that continuously monitor and adjust the voltage levels. The first biasing circuit receives feedback from the operating conditions of the first transistor and adjusts its gate voltage accordingly, while the second biasing circuit does the same for the second transistor. This feedback control ensures that transistors remain within safe operation limits, preventing excessive leakage current while maintaining normal circuit operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The biasing circuits serve as intermediary elements between the power supply and the transistors. Instead of directly applying voltage from the power supply to the transistor gates, the biasing circuits act as mediators that condition and regulate the voltage levels. This intermediary function allows the circuit to maintain normal operation while preventing transistors from entering unsafe operation regions that would generate harmful leakage current.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If multiple supply voltages and biasing circuits are added, then transistor operation is stabilized, but circuit complexity increases

Engineering Contradiction:
Improvetransistor operation stabilityVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing biasing circuits that perform multiple functions simultaneously. The first biasing circuit not only adjusts the gate voltage of the first transistor but also helps regulate the overall voltage levels in the circuit. Similarly, the second biasing circuit serves multiple purposes including gate voltage adjustment and protection against voltage spikes. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in circuit complexity while achieving reliable transistor operation stabilization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3346474B1Driving circuit for non-volatile memory
Publication Date: 2019.08.28 EMEMORY TECH INC
  • EP3346474B1 patent drawingFigure 1~2
  • EP3346474B1 patent drawingFigure 3A~3C
  • EP3346474B1 patent drawingFigure 4A

AI summary

A driving circuit includes a first driver, a switching circuit and a second driver. The first driver receives an input signal and an inverted input signal, and generates a driving signal. The switching circuit receives the driving signal and a first mode signal. Moreover, an output signal is outputted from an output terminal. The second driver is connected with the output terminal.