Voltage Threshold Detector Using Diode Drop for Glitch Protection
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Solution Overview
Problem
Integrated circuits are vulnerable to voltage variations, which can lead to security breaches through voltage attacks, damage to components, and timing failures.
Innovation Solution
A voltage variation detector is implemented, comprising a transistor stack, a transistor diode, and an inverter, which monitors the operating voltage and generates a detection signal when the voltage crosses a predefined threshold, triggering defensive actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage attacks are launched to extract secure information, then hackers can cause hold violations and read out information through JTAG outputs, but implementing traditional voltage detection methods with analog references and clock references increases cost and complexity
Solution Approach 1:
The patent extracts the voltage detection function from complex analog reference circuits and clock reference systems, implementing a simplified digital-only detection mechanism using transistor stacks and logic gates that operates independently of analog references and clock signals
Solution Approach 2:
The patent replaces expensive, complex analog reference circuits with inexpensive digital logic components (transistor stacks, inverters, AND gates) that provide adequate voltage detection functionality without requiring precision analog components
2Reliability
If voltage glitches cause setup time failures on security engine control logic, then security checks can be bypassed giving complete access to secured content, but traditional detection methods require expensive analog references
Solution Approach 1:
The patent substitutes analog reference-based detection mechanisms with a digital logic-based system using transistor stacks and logic gates, eliminating the need for expensive analog references while maintaining detection capability for voltage glitches that could bypass security checks
3Reliability
If rapid voltage changes due to workload affect chip operation, then localized voltage drops can occur, but implementing comprehensive voltage monitoring increases device complexity
Solution Approach 1:
The patent segments the voltage monitoring function into discrete transistor stack units, each corresponding to a specific voltage threshold, allowing distributed monitoring of different voltage levels without requiring a monolithic complex monitoring circuit
Solution Approach 2:
The transistor stack-based detection circuit serves multiple functions: detecting overvoltage conditions, detecting undervoltage conditions, and providing threshold-based monitoring across different voltage levels, replacing multiple specialized circuits with a single versatile mechanism
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 voltage variation detector provides fast and efficient detection of voltage glitches and droops, enabling protective measures to prevent data breaches and component damage, while reducing the need for expensive analog references and clock references.
Implementation Method 1
detecting at least one transition of a voltage across a voltage threshold, wherein the detecting is based on a transistor diode being reversed biased
Data Source
AI summary
The disclosure provides a voltage detecting circuit that detects voltage increases and voltage decreases using a diode drop and voltage thresholds. The voltage detecting circuit, referred to as a voltage variation detector, uses the diode to maintain a differential between the voltage being monitored and a voltage threshold. When the diode is reversed bias, the voltage variation detector generates a detecting signal indicating the monitored voltage crossed the voltage threshold. In one example a voltage variation detector is disclosed that includes: (1) a transistor stack that corresponds to a voltage threshold, (2) a transistor diode, and (3) an inverter that receives an input signal and provides an detection signal that controls one or more gates of the transistor stack, wherein the transistor stack and the transistor diode provide the input signal and the detection signal indicates when the voltage crosses the voltage threshold.