Random Number Generator Circuit Using Differential Amplifier and XOR Logic

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Solution Overview

Problem

Existing random number generators face challenges in achieving high bit rates while maintaining a compact circuit scale, particularly when utilizing high-frequency components of flicker noise, as they often require high-gain circuits that are sensitive to low-frequency components and necessitate multiple comparators and reference voltages.

Innovation Solution

A random number generator design incorporating a differential amplifier, multiple binarization circuits with distinct threshold values, and an exclusive OR circuit to generate random number sequences, allowing for high bit rates without increasing circuit complexity by utilizing high-frequency components of flicker noise effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a high-gain circuit is used to amplify high-frequency noise components, then the amplification factor is improved, but the circuit becomes sensitive to low-frequency components and the input voltage range is restricted

Engineering Contradiction:
Improveamplification factorVSAvoidcircuit sensitivity to low-frequency components
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent segments the noise signal processing into two independent paths: one path handles high-frequency components through a differential amplifier with bandwidth limiter, while another path handles low-frequency components separately. This segmentation allows each path to be optimized independently, resolving the contradiction between amplification factor and sensitivity to low-frequency components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a bandwidth limiter as an intermediary component between the differential amplifier and subsequent circuitry. This intermediary restricts the amplifier's bandwidth to pass only high-frequency components, preventing low-frequency components from affecting the amplification process while maintaining high amplification factor for the desired frequency range.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple comparators with different threshold voltages are used to generate binarized signals, then the random number generation quality is improved, but the circuit scale increases

Engineering Contradiction:
Improverandom number generation qualityVSAvoidcircuit scale
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple comparators into a single differential amplifier followed by a single comparator with a reference voltage. The differential amplifier performs the threshold comparison function that would otherwise require multiple comparators with different threshold voltages, thereby reducing circuit scale while maintaining the ability to generate multiple binarized signals through subsequent logic operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes a single comparator circuit universal by using it in combination with a differential amplifier that can be configured to provide multiple effective threshold levels. The same comparator hardware serves multiple comparison functions by processing the amplified differential signal, eliminating the need for multiple dedicated comparator circuits.

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

3Quantity of substance

If flicker noise is used for random number generation, then the noise intensity is improved, but the low-frequency components dominate and prevent high bit rate generation

Engineering Contradiction:
Improvenoise intensityVSAvoidbit rate
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The patent dynamically controls the frequency response of the amplification stage by introducing a bandwidth limiter with a cutoff frequency that can be set to pass only high-frequency components of the flicker noise. This dynamic frequency selection allows the system to exploit the high intensity of flicker noise while excluding the dominant low-frequency components that would limit the bit rate.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the frequency domain parameters of the noise signal by using a differential amplifier configured with specific bandwidth limitations. By adjusting the amplifier's bandwidth and center frequency, the system transforms the spectral distribution of the flicker noise to emphasize high-frequency components, enabling high bit rate generation while maintaining the advantage of high noise intensity.

Inventive Principle:
Principle #35Parameter changes

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

This design achieves a high bit rate in random number generation while preventing circuit scale expansion, using high-frequency components of flicker noise and reducing the need for multiple comparators and threshold voltage generation, thus enhancing the stability and efficiency of the random number generation process.

Implementation Method 1

an amplifier to amplify a difference between a noise signal and a reference signal to generate an amplified signal

Methodology Applied
Scientific EffectDifferential amplification:

Implementation Method 2

a plurality of binarization circuits configured to binarize the amplified signal by using different inherent threshold values to obtain a plurality of binarized signals

Methodology Applied
Scientific EffectThreshold comparison:

Implementation Method 3

an exclusive OR circuit to perform an exclusive OR operation on the a plurality of binarized signals to generate random number sequence

Methodology Applied
Scientific EffectLogical operation:

Data Source

PatentEP1975780B1Random number generator
Publication Date: 2009.09.23 KK TOSHIBA
  • EP1975780B1 patent drawingFigure 1~2
  • EP1975780B1 patent drawingFigure 3A~3C
  • EP1975780B1 patent drawingFigure 4

AI summary

A random number generator includes an amplifier (101) to amplify a difference between a noise signal and a reference signal to generate an amplified signal, a plurality of binarization circuits (102-1,...,102-n) configured to binarize the amplified signal by using different inherent threshold values to obtain a plurality of binarized signals, and an exclusive OR circuit (103) to perform an exclusive OR operation on the a plurality of binarized signals to generate random number sequence.