Anti-Fuse Circuit Long-Pulse Detection for Write Protection
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Solution Overview
Problem
Existing semiconductor devices using anti-fuse elements for one-time programmable memory are prone to circuit defects and abnormalities due to unintentional DC current flow when erroneous DC voltage is applied, leading to unintended dielectric breakdown.
Innovation Solution
Incorporating a long-pulse detection circuit that stops the transistor drive based on a detection signal, preventing the flow of unintentional DC current to the anti-fuse element by detecting abnormal signals and halting the writing operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a write pulse is applied to the anti-fuse element for programming, then the anti-fuse element can be programmed successfully, but if a DC voltage is erroneously applied instead of a write pulse, then unintentional DC current flows causing circuit defects or abnormality
Solution Approach 1:
The long-pulse detection circuit performs preliminary detection of the write signal pulse width before the programming operation proceeds. By detecting whether the pulse exceeds a predetermined duration threshold, the circuit proactively identifies erroneous DC voltage conditions and prevents them from causing damage to the anti-fuse element, thus resolving the contradiction between enabling programming and preventing harmful DC current flow.
Solution Approach 2:
The long-pulse detection circuit continuously monitors the write signal and provides feedback to the control circuit. When an abnormal pulse duration is detected, the feedback mechanism triggers the control circuit to stop the programming operation, creating a closed-loop control system that prevents unintentional DC current flow while allowing normal programming operations to proceed.
2Reliability
If continuous monitoring of write signals is performed to detect long pulses, then circuit safety is improved, but device complexity increases due to additional detection circuit
Solution Approach 1:
The long-pulse detection circuit is implemented with localized functionality, focusing specifically on pulse width detection rather than comprehensive signal analysis. By concentrating the monitoring function on a single critical parameter (pulse duration) and using a dedicated detection circuit with a predetermined threshold, the solution achieves reliable safety monitoring without excessive complexity.
Solution Approach 2:
The detection circuit operates by comparing the write signal pulse width against a predetermined threshold parameter. This parameter-based approach allows the circuit to distinguish between normal programming pulses and erroneous DC voltage conditions using a simple threshold comparison mechanism, achieving effective monitoring with minimal circuit complexity.
Data Source
AI summary
A semiconductor device includes: a semiconductor substrate; an anti-fuse element arranged on the semiconductor substrate and connected to a first terminal with a first potential; a first transistor arranged on the semiconductor substrate and connected between the anti-fuse element and a second terminal with a second potential different from the first potential; a logic circuit connected to a gate of the first transistor; and a long-pulse detection circuit connected to the logic circuit. The long-pulse detection circuit is connected to a third terminal into which a write signal for the anti-fuse element is inputted, and drive of the first transistor is stopped based on a long-pulse detection signal outputted from the long-pulse detection circuit.