Adaptive Supply Voltage Glitch Sensing for Compact IC Detection
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Solution Overview
Problem
Existing power supply disturbance detectors in integrated circuits are inefficient due to high variability in transistor threshold voltages, large size, and inability to detect disturbances within tolerance ranges specific to different power supply voltages, leading to operational limitations and increased electrical consumption.
Innovation Solution
A compact power supply disturbance detection circuit using a voltage comparator and operational transconductance amplifier with adaptive reference voltages, allowing for precise detection of transient voltage variations independent of component variability and adaptable to various power supply voltages, utilizing a filter capacitor for high-pass filtering and reducing component size and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transistor threshold voltage detection is used, then detection simplicity is improved, but manufacturing precision deteriorates due to high variability in transistor threshold voltages
Solution Approach 1:
The patent introduces an operational amplifier as an intermediary component between the power supply voltage and the transistor threshold voltage detector. The operational amplifier amplifies the voltage difference between the power supply voltage and the reference voltage (which includes the transistor threshold voltage), thereby compensating for the variability in transistor threshold voltages and enabling precise detection despite manufacturing variations.
Solution Approach 2:
The patent changes the detection parameter from directly monitoring transistor threshold voltage to monitoring the amplified voltage difference through an operational amplifier. This parameter transformation allows the system to overcome the limitations of transistor threshold voltage variability while maintaining detection simplicity.
2Use of energy by moving object
If low power supply voltage is used, then energy consumption is reduced, but detection precision deteriorates because power supply variations become much lower than transistor threshold voltage levels
Solution Approach 1:
The patent implements a dynamic detection mechanism using an operational amplifier that continuously monitors and amplifies voltage variations. This dynamic approach enables the detection of small power supply variations even at low voltage levels, maintaining detection precision while allowing the system to operate at reduced power consumption.
Solution Approach 2:
The patent embeds the disturbance detection function within the existing low-voltage power supply structure by using the operational amplifier to detect variations nested within the normal operating voltage range. This allows detection of disturbances without requiring separate high-voltage detection circuits, thus maintaining low overall power consumption.
3Reliability
If RC filters with high capacitance are used, then filtering performance is improved, but device area increases due to large capacitor size
Solution Approach 1:
The patent replaces the traditional RC filter mechanism with an active filtering approach using an operational amplifier. The operational amplifier provides the necessary filtering function through its gain and frequency response characteristics, eliminating the need for large physical capacitors and reducing the overall circuit area while maintaining or improving filtering performance.
4Device complexity
If fixed threshold detection is used, then device complexity is reduced, but adaptability deteriorates because detectors cannot adjust to different power supply voltage values
Solution Approach 1:
The patent implements a dynamic reference voltage system where the reference voltage is derived from a voltage divider that scales with the power supply voltage. Combined with the operational amplifier's ability to amplify varying voltage differences, this creates an adaptive detection system that automatically adjusts to different power supply voltage levels without requiring complex switching or configuration circuits.
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 precise detection of power supply disturbances across a range of voltages, reducing size and power consumption while maintaining detection sensitivity, allowing for effective countermeasures against fault injection attacks and improving operational reliability.
Implementation Method 1
A filter capacitor is provided in series between a power supply terminal and the second input of the voltage comparator
Data Source
AI summary
A circuit includes a voltage comparator with an output, a first input and a second input, the first input being coupled to a first reference voltage terminal. An operational transconductance amplifier has an output coupled to the second input of the voltage comparator, an inverting input coupled to the output of the operational transconductance amplifier, and a non-inverting input coupled to a second reference voltage terminal. A filter capacitor is coupled in series between a power supply terminal and the second input of the voltage comparator.