Voltage Sensing Circuit with Self-Referencing Attack Detection
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Solution Overview
Problem
Existing semiconductor devices face challenges in reliably monitoring and securing circuits from external malicious attacks, as monitoring systems themselves can be compromised, leading to unreliable security and operation.
Innovation Solution
A semiconductor device with a voltage sensing circuit and comparing circuit, utilizing a current mirror structure with transistors and resistive elements, generates monitoring output signals to determine if target voltages are within reference ranges, autonomously recognizing and processing deviations due to external attacks without relying on external inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a monitoring circuit is used to monitor signals supplied to each of the plurality of circuits, then security information leakage is prevented, but the monitoring circuit itself can be compromised by external malicious attacks, leading to unreliable security
Solution Approach 1:
The patent changes the parameter of voltage monitoring by introducing a self-referencing mechanism where the monitoring circuit compares its own internal reference voltage with the target voltage. This allows the circuit to detect voltage deviations caused by external attacks by monitoring changes in its own operating parameters, thereby maintaining security reliability even when external reference voltages are compromised.
Solution Approach 2:
The monitoring circuit performs self-diagnosis by using its own internal reference voltage and comparing it with the target voltage. The circuit can autonomously detect when it is under attack by monitoring changes in its own operation, eliminating the need for external trusted reference sources that could be compromised by malicious attacks.
2Measurement precision
If external reference voltages are used for monitoring, then voltage levels can be compared, but external attacks on reference voltages render the monitoring unreliable
Solution Approach 1:
The patent introduces an internal reference voltage as an intermediary element that mediates between the target voltage and the comparison operation. This internal reference voltage serves as a trusted reference that is generated within the monitoring circuit itself, preventing external attacks from compromising the reference source and maintaining measurement precision and reliability simultaneously.
Solution Approach 2:
Instead of using external reference voltages as the basis for comparison, the patent inverts the approach by using the target voltage itself as one input and comparing it with an internally generated reference. This inversion makes the monitoring circuit immune to external attacks on reference voltages, as the reference is now internal and controlled by the monitoring circuit itself.
Data Source
AI summary
A semiconductor device is provided and includes: a voltage sensing circuit configured to output first and second sensing voltages based on a target voltage applied thereto; and a comparing circuit configured to generate a monitoring output signal based on levels of the first and second sensing voltages, wherein the voltage sensing circuit includes: a first transistor including a gate to receive a reference bias voltage, a source connected to an input node, and a drain connected to one end of a first resistive element; a second transistor provided in a current mirror structure with the first transistor, and including a drain connected to a third resistive element; and a second resistive element connected to another end of the first resistive element, the first sensing voltage being provided to both ends of the second resistive element, and the second sensing voltage being provided to both ends of the third resistive element.