Starvation-Voltage Random Number Generator Circuit
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Solution Overview
Problem
Existing random number generation methods in digital systems, particularly in integrated circuits, face challenges in producing high-entropy random numbers efficiently, especially when operating outside specified voltage ranges, which can lead to biased and predictable delays rather than truly random outcomes.
Innovation Solution
The proposed solution involves using a signal-source circuit (SSC) operating at a 'starvation' power-supply voltage below the specified range, where logic gates still function but do not meet all electrical parameters, resulting in noisy outputs with high entropy delays. This is achieved through a SSC power supply circuit (SSC-PS) that generates a reduced voltage, and a digitization circuit that samples these noisy outputs to generate random numbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the SSC is powered with a reduced voltage below the specified operating range, then the output signal entropy is improved, but the electrical parameter specifications are not met
Solution Approach 1:
The patent changes the operating voltage parameter of the signal-source circuit from the specified operating range to a reduced voltage below that range. This parameter change increases thermal noise and propagation delay variations, thereby improving output entropy while accepting that electrical parameters will not meet specifications. The digitization circuit then processes this noisy output to generate random numbers.
2Loss of information
If the SSC operates at starvation voltage to generate noisy output, then the randomness of output is improved, but the logical functionality may fail
Solution Approach 1:
The patent applies partial action by reducing the voltage to a level that is sufficient to maintain basic logical functionality but insufficient to meet full electrical specifications. This allows the circuit to operate in a marginal state where logic functions are preserved while thermal noise effects are enhanced, providing the needed randomness without complete functional failure.
Solution Approach 2:
The patent converts the harmful effect of voltage reduction (which causes electrical parameter failures and potential logic errors) into a beneficial effect. By deliberately operating at starvation voltage, the increased thermal noise and propagation delay variations become the source of high-entropy random numbers, transforming a reliability problem into a randomness advantage.
3Device complexity
If the SSC-PS connects the SSC to a fixed reduced voltage, then the circuit complexity is reduced, but the oscillation frequency control precision is worsened
Solution Approach 1:
The patent extracts the voltage regulation function from the system by using a fixed reduced voltage provided by the SSC-PS. This removes the need for complex feedback control circuits, simplifying the overall design. The fixed voltage is sufficient to maintain the circuit in the starvation regime needed for random number generation, even if it provides less precise frequency control.
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 approach effectively generates random numbers with high entropy by exploiting the increased variations in propagation delays due to thermal noise, even when operating outside typical voltage specifications, enhancing the randomness and unpredictability of the output signals.
Implementation Method 1
The SSC-PS is configured to power the SSC with a reduced voltage that is below the specified operating voltage range, thereby causing the output signal to be noisy
Data Source
AI summary
An integrated circuit includes signal-source circuitry (SSC), an SSC power supply circuit (SSC-PS) and a digitization circuit. The SSC is configured to generate an output signal, which is guaranteed to meet specified electrical parameters provided that a supply voltage to the SSC is within a specified operating voltage range. The SSC-PS is configured to power the SSC with a reduced voltage that is below the specified operating voltage range, thereby causing the output signal to be noisy. The digitization circuit is configured to digitize the noisy output signal so as to generate a respective sequence of random numbers.