Intermittent Open-Circuit Detection in IC Wire Mesh
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Solution Overview
Problem
Conventional wire-mesh tamper-detection systems in integrated circuits require constant power to detect tampering, leading to higher costs and manufacturing expenses due to the continuous power draw and the need for larger resistors.
Innovation Solution
Implementing a low-power, active open-circuit detection system that checks for open-circuit conditions intermittently using a pseudo-random binary sequence and switch control to reduce power consumption and allow for smaller resistor sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant power is supplied to the wire-mesh tamper-detection system, then the system can continuously monitor for tampering, but power consumption increases and manufacturing costs rise
Solution Approach 1:
The patent implements periodic monitoring by using a pseudo-random binary sequence generator to intermittently activate detection circuits. Instead of continuous monitoring, the system checks for open-circuit conditions at random intervals determined by the pseudo-random sequence, significantly reducing power consumption while maintaining effective tamper detection capability.
Solution Approach 2:
The patent introduces dynamic control of the detection system through switchable circuit paths controlled by pseudo-random binary sequences. The monitoring activity transitions from static continuous operation to dynamic intermittent operation, allowing the system to adapt power consumption levels while maintaining security effectiveness.
2Measurement precision
If larger resistors are used in the wire-mesh system, then detection sensitivity improves, but manufacturing costs and device area increase
Solution Approach 1:
The patent changes the operational parameters of the detection system by using intermittent measurement cycles instead of continuous monitoring. This allows the use of smaller resistors because the detection sensitivity is maintained through repeated periodic checks rather than requiring large resistors for continuous high-sensitivity operation. The pseudo-random timing provides sufficient detection probability with reduced component sizes.
Data Source
AI summary
An open-circuit detection system for an integrated circuit (IC) includes a wire (e.g., part of a wire mesh for device protection) and circuitry for detecting open-circuit conditions in the wire. A first signal generator (e.g., a linear-feedback shift register) applies a binary sequence to a first end of the wire. Switched resistors are connected between a second end of the wire and both a voltage supply and ground. A comparator compares the binary sequence and a signal based on the voltage at the second end of the wire to check for the open-circuit condition. Logic circuitry closes one of the first and second switches as a function of a value in the binary sequence. The comparator checks for the open-circuit condition in the wire randomly and intermittently, which reduces power consumption.