Ring Oscillator Voltage Glitch Detection With Digital Counters

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Solution Overview

Problem

Current voltage glitch detection methods, particularly analog sensors, are not easily implementable in digital semiconductor fabrication processes and are not portable to advanced processes like the 16 nanometer fin FET process, making them ineffective against supply voltage glitch attacks.

Innovation Solution

A digital voltage glitch detection circuit utilizing a ring oscillator with multiple counters and a combined result circuit that compares the combined count values with a reference value to detect voltage glitches, allowing for high-resolution detection of momentary voltage transients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If analog glitch sensors are used for voltage detection, then voltage glitch detection capability is achieved, but ease of manufacture in digital semiconductor fabrication deteriorates

Engineering Contradiction:

Improvevoltage glitch detection capabilityVSAvoidease of manufacture in digital semiconductor fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces analog sensing mechanisms with a digital detection system based on ring oscillators and counters. The ring oscillator converts voltage variations into frequency changes, which are then counted and processed digitally. This substitution of analog sensing with digital measurement enables compatibility with digital semiconductor fabrication processes while maintaining voltage glitch detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If analog glitch sensors are used for voltage detection, then voltage glitch detection capability is achieved, but adaptability to advanced semiconductor processes deteriorates

Engineering Contradiction:

Improvevoltage glitch detection capabilityVSAvoidadaptability to advanced semiconductor processes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If ring oscillator with multiple counters is used for voltage detection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvedetection resolutionVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the detection function into multiple independent counters, each counting oscillations during a specific time interval. This segmentation allows the system to achieve high measurement precision by combining results from multiple counters while keeping each individual counter relatively simple. The multiple counters work in parallel to provide both high resolution and robustness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic counting intervals where multiple counters operate during different time periods. By distributing the counting function across multiple time intervals and counters, the system achieves high measurement precision without requiring a single complex counter, thereby managing device complexity through temporal distribution of functions.

Inventive Principle:

Principle #19Periodic 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 enables the detection of short-duration voltage transients with improved resolution and portability across different semiconductor processes, effectively addressing the limitations of existing analog sensors.

Implementation Method 1

the ring oscillator is a voltage-controlled ring oscillator having a plurality of series-connected stages connected in a continuous ring so that an output of one stage is connected to an input of a subsequent stage

Methodology Applied

Scientific EffectVoltage-controlled oscillation:

Data Source

PatentUS11947672B2Voltage glitch detection circuit

Publication Date: 2024.04.02 NXP BV

AI summary

A voltage glitch detector includes a ring oscillator, a plurality of counters, a combined result circuit, and a result evaluation circuit. The ring oscillator includes a plurality of series-connected stages. An output of a last stage of the ring oscillator is coupled to an input of a first stage of the ring oscillator. Each counter of the plurality of counters has an input coupled to a node located between two stages of the plurality of series-connected stages. The combined result circuit is coupled to each of the plurality of counters. The combined result circuit combines the count values received from each counter of the plurality of counters to provide a combined result. The result evaluation circuit is coupled to compare the combined result with a reference value to determine when a voltage glitch is detected.