ADC Digital Calibration for True Random Number Accuracy

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Solution Overview

Problem

The calibration accuracy of compensation parameters in analog-to-digital converters (ADCs) used in true random number generator circuits is low, affecting the randomness of generated random numbers.

Innovation Solution

A digital calibration method that iteratively selects and tests compensation calibration code values within a predefined range to determine the optimal calibration code by sampling the ADC's output multiple times and adjusting the calibration code until the output meets specified accuracy criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional calibration methods are used for ADC compensation parameters, then the calibration process is simple, but the calibration accuracy is low

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the ADC output is sampled multiple times, the results are counted and compared against expected ranges, and the compensation parameter is adjusted based on whether the count falls within the acceptable range. This closed-loop feedback process iteratively refines the calibration accuracy by continuously monitoring and adjusting the compensation parameter until the output meets the specified accuracy criteria.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary actions by pre-defining the acceptable range for the calibration code and pre-setting the sampling次数 before actual calibration begins. These preliminary preparations establish the criteria for successful calibration in advance, allowing the calibration process to systematically test and verify compensation parameters against known good ranges, thereby improving accuracy without requiring complex real-time decision-making.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple sampling and iterative testing are performed to improve calibration accuracy, then the calibration precision improves, but the calibration time increases

Engineering Contradiction:
Improvecalibration precisionVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing a fixed number of sampling operations rather than continuous monitoring, and by testing compensation parameters in discrete steps rather than continuously. This approach achieves sufficient calibration precision through a limited number of targeted measurements, avoiding unnecessary time consumption while still meeting the accuracy requirements for true random number generation.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The calibration process uses periodic action by sampling the ADC output at regular intervals and systematically iterating through different compensation parameter values. This structured periodic approach allows the system to efficiently explore the parameter space and converge on an accurate calibration value without requiring constant monitoring, thus balancing precision with time efficiency.

Inventive Principle:
Principle #19Periodic action

3Reliability

If the ADC compensation parameter calibration is not accurate, then the calibration process is fast, but the randomness of the true random number generator output deteriorates

Engineering Contradiction:
Improverandomness qualityVSAvoidcalibration circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex analog calibration circuits with a digital calibration approach that uses software-based iterative testing and counting. Instead of relying on complex hardware calibration mechanisms, the system uses digital sampling, counting, and comparison operations to achieve accurate compensation parameter calibration, thereby improving reliability while avoiding the need for complex calibration circuitry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses copying by creating multiple copies of the ADC output through repeated sampling and using these copies to perform statistical analysis (counting). By generating multiple identical copies of the signal and analyzing their collective behavior, the system can accurately determine the compensation parameter without requiring complex single-shot calibration circuits, thus improving randomness quality through a relatively simple calibration approach.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3836404B1Digital calibration method, digital calibration device and true random number generator circuit
Publication Date: 2022.12.07 SHENZHEN GOODIX TECH CO LTD
  • EP3836404B1 patent drawingFigure 1
  • EP3836404B1 patent drawingFigure 2
  • EP3836404B1 patent drawingFigure 3

AI summary

A digital calibration method, a device, and a true random number generator circuit are provided. In one aspect, the embodiment of the present disclosure uses the digital calibration method to calibrate compensation of a circuit to be calibrated, output of the circuit to be calibrated is sampled and tested multiple times, and whether a current test compensation calibration code value can make the circuit to be calibrated meet specified accuracy is judged based on a probability that the output result is a target result. Through sampling the output of the circuit to be calibrated multiple times, the selected compensation calibration code has higher accuracy. Therefore, the technical solution provided by the embodiments of the present disclosure can solve a problem of low calibration accuracy of the circuit for calibrating compensation in the prior art.