Edge-Detected TRNG Circuit for Reliable Noise Digitization

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Solution Overview

Problem

Existing truly random number generator (TRNG) circuits face challenges in digitizing noise signals due to unpredictable variation ranges, making them difficult to configure and prone to operational failures.

Innovation Solution

A random number generator circuit that utilizes a noise source with random telegraph noise, an edge detector to produce voltage pulses, and an analogue-to-digital converter to generate a random bit sequence, where the voltage pulses have a known amplitude range, simplifying digitization and preventing operational failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple comparator and D flip-flop are used to digitize the noise signal, then the circuit is compact and inexpensive to manufacture, but the circuit becomes inoperative because the reference voltage may not be located in the variation range of the noise signal

Engineering Contradiction:

Improvemanufacturing cost and circuit simplicityVSAvoidoperational reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by using an edge detector to pre-process the noise signal and generate voltage pulses with known amplitude ranges before digitization. This preliminary transformation ensures that the subsequent comparator can reliably compare against a fixed reference voltage, eliminating the reliability issue while maintaining circuit simplicity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The edge detector acts as an intermediary component between the noise source and the comparator. It transforms the unpredictable noise signal into standardized voltage pulses with known characteristics, enabling the simple comparator to function reliably without requiring complex adaptive reference voltage mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a predefined reference voltage is used for digitization, then the circuit structure is simplified, but the circuit risks becoming inoperative due to unpredictable noise signal variation ranges

Engineering Contradiction:

Improvedigitization circuit complexityVSAvoidadaptability to noise signal variations

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter characteristics of the signal being digitized. By transforming the noise signal through an edge detector to produce voltage pulses with known amplitude ranges, the signal parameters become predictable and suitable for comparison with a fixed reference voltage, resolving the contradiction between simple circuit structure and adaptability to noise variations.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the noise signal is digitized directly without edge detection, then the configuration is simpler, but the variation range of the noise signal makes digitization difficult and unpredictable

Engineering Contradiction:

Improveconfiguration easeVSAvoiddigitization precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The edge detector performs preliminary action by detecting transitions in the noise signal and generating standardized voltage pulses before digitization. This pre-processing step establishes known amplitude ranges that enable precise and reliable digitization while maintaining ease of configuration, as the comparator only needs a fixed reference voltage.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a reliable and simpler-to-configure TRNG circuit that effectively generates random bits, resistant to temperature variations and secure for cryptographic applications, with improved resistance to noise source deviations.

Implementation Method 1

The present invention relates to a random number generator circuit... TRNGs are electronic circuits that produce the randomness from a physical entropy source, by transformation of analogue signals into digital signals. The physical entropy source is generally a noise source, for example the thermal noise of a semiconductor device... This TRNG circuit 10 makes use of the random telegraph noise (RTN), produced by a resistive random access memory 11 (RRAM). This noise results from the trapping and detrapping of electrons in the vicinity of the conductive path

Methodology Applied

Scientific EffectRandom telegraph noise:

Implementation Method 2

an edge detector configured to produce voltage pulses, each voltage pulse corresponding to a rising or falling edge of the noise signal

Methodology Applied

Scientific EffectEdge detection:

Implementation Method 3

an analogue-to-digital converter configured to generate a random bit sequence from voltage pulses... The digitisation of the analogue signal can thus be carried out by comparing it to a non-zero reference value less than the supply voltage of the edge detector

Methodology Applied

Scientific EffectAnalogue-to-digital conversion:

Data Source

PatentUS12131131B2Random number generator circuit

Publication Date: 2024.10.29 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

A random number generator circuit includes a noise source capable of providing a noise signal that varies randomly; and a circuit for extracting the noise signal including an edge detector configured to produce from the noise signal an analogue signal including voltage pulses, each voltage pulse corresponding to a rising or falling edge of the noise signal, and an analogue-to-digital converter configured to generate a random bit sequence from the analogue signal.