E-Fuse Trim Circuit With Current Mirroring and Fault Tolerance
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Solution Overview
Problem
Current trim circuits for e-fuse units occupy large circuit areas and fail to operate normally when one of the elements is damaged.
Innovation Solution
A trim circuit design that includes a mirroring device and a driving transistor, where the mirroring device generates a driving voltage to turn on the driving transistor, allowing the e-fuse unit to be melted to a high impedance state, even if one of the elements is damaged, using a current mirror configuration with protection and current prohibition circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional trim circuit design is used, then the e-fuse unit can be melted, but the circuit occupies a large circuit area
Solution Approach 1:
The patent combines the protection function and current prohibition function into the same circuit structure using shared transistors (T13, T14) and control signals. The mirroring device integrates multiple control transistors (T12-1, T12-2) that simultaneously provide current mirroring and protection capabilities, reducing the overall circuit area while maintaining all required functions.
Solution Approach 2:
The control transistor T14 serves multiple functions: it acts as a current prohibition device that can block current flow to protect the e-fuse unit, and simultaneously functions as part of the mirroring device control structure. This multi-functionality reduces the number of discrete components needed, thereby reducing circuit area.
2Area of stationary object
If a compact circuit design is used to reduce circuit area, then the circuit size is minimized, but the circuit may fail when elements are damaged
Solution Approach 1:
The patent segments the control function into multiple transistors (T12-1, T12-2, T13, T14) that work in parallel and can compensate for each other. This segmentation provides redundancy within a compact structure, where if one transistor fails, others can maintain circuit operation. The segmented design achieves both area reduction through integration and reliability through distributed control paths.
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 reduces the circuit area and ensures normal operation of the trim circuit even when one of the elements is damaged, achieving efficient melting of the e-fuse unit while minimizing circuit size.
Implementation Method 1
When the mirroring device is triggered by the enable signal, the mirroring device generates a driving voltage. In response to the driving voltage generated by the mirroring device, the driving transistor is turned on to generate an MOS current to an output node coupled to the e-fuse unit. In response to the MOS current transmitted from the output node, the e-fuse unit is melted to a high impedance state.
Data Source
AI summary
A trim circuit for an e-fuse unit includes: a mirroring circuit for receiving an enable signal, when triggered by the enable signal, the mirroring circuit generating a driving voltage; and a driving transistor coupled to the mirroring circuit, in response to the driving voltage from the mirroring circuit, the driving transistor turning ON to generate a MOS current to an output node, wherein the output node is coupled to the e-fuse unit, and in response to the MOS current from the output node, the e-fuse unit is burned out.