A detection circuit for active shielded wiring

Abstract

The invention relates to a detection circuit of active shielding wiring, and belongs to the technical field of safety protection detection of chips. The circuit comprises a first-stage amplifier, a stored-value circuit, a second-stage amplifier, an A / D converter, a CPU controller, a write-once memory and a comparator. The first-stage amplifier is composed of a first amplifier, a plurality of switches and a plurality of detected shielded wires. One end of the stored-value circuit is connected with the output end of the first-stage amplifier. The other end of the stored-value circuit is connected with the positive input end of the second-stage amplifier. The input end of the A / D converter is connected with the output end of the second-stage amplifier. The output end of the A / D converter is connected with the input end of the comparator. The CPU controller is respectively connected with the first-stage amplifier and the write-once memory. The write-once memory is connected with the CPU controller and the comparator. The input end of the comparator is respectively connected with the output end of the write-once memory and the output end of the A / D converter. The detection circuit can reduce the influences of mismatch of the circuit, the process bias of the circuit and the temperature of the circuit, and therefore the accuracy of the detection circuit is improved.

Description

technical field [0001] The invention belongs to the technical field of chip safety protection detection, and particularly relates to a detection circuit in an active shielding wiring safety chip. Background technique [0002] Through active shielding and wiring, preventing FIB (Focused Ion Beam, focused ion beam) attacks has been widely used in chip physical protection technology. There are many ways to detect shielded wires, but most of them can only detect shielded wire breaks caused by FIB, or short circuits in a very large range, but cannot effectively detect shielded wires that are next to a small section of shielded wires. The road changes. The safety of physical protection requires that the shielded wire detection circuit can effectively detect the bypass change of the shielded wiring. [0003] At present, there are mainly four detection methods for shielded wires: comparing charge, comparing potential, comparing delay and comparing signal integrity. The principle ...

AI Technical Summary

Problems solved by technology

It is still relatively delayed in nature

The disadvantage of the second, third, and fourth detection methods is that the detection accuracy is low, and it is difficult to detect the shielded wire bypass processing caused by FIB

[0005] At present, the applicant has not seen any domestic and foreign research on detection circuits for shielding wire resistance comparison

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