Electrical Fuse Circuit Misprogramming Prevention
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Solution Overview
Problem
Electrical fuses in system LSI circuits are prone to misprogramming when the power source is turned ON/OFF or when partial power or ground connections are cut off or recovered, due to unstable voltage levels and misalignment of VDD_IO and VDD_CORE voltages.
Innovation Solution
An electrical fuse circuit configuration that includes a series circuit of a fuse device and a MOS transistor, a logic circuit with controlled gate inputs, a common program power source, and potential fixing means to ensure the MOS transistor remains nonconductive unless explicitly enabled for programming, preventing misprogramming by maintaining a nonactivation level when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If VDD_IO power source is used for programming fuse device, then sufficient current for programming is ensured, but misprogramming occurs when VDD_IO is applied before VDD_CORE due to unstable level shifter output
Solution Approach 1:
The patent applies preliminary action by enabling the fuse programming function only after VDD_CORE is confirmed to be applied. The detection circuit checks the VDD_CORE voltage status before allowing the MOS transistor to become conductive, ensuring that the control circuit is properly powered before programming operations commence. This prevents misprogramming that would occur if the level shifter operated with unstable voltage conditions.
Solution Approach 2:
The patent implements feedback through a detection circuit that monitors VDD_CORE voltage status and uses this information to control the programming operation. The detection circuit provides feedback signals to the control logic, which then determines whether to enable the MOS transistor. This feedback mechanism ensures that programming only occurs when both VDD_IO and VDD_CORE are properly applied, preventing misprogramming while maintaining sufficient programming current.
2Loss of energy
If power source or ground is cut off for leakage current suppression, then power consumption is reduced, but misprogramming occurs when cut-off timing is slightly delayed
Solution Approach 1:
The patent applies preliminary action by establishing a确定的 control signal state before power or ground is cut off. The detection circuit ensures that the MOS transistor gate is properly controlled based on VDD_CORE status before leakage suppression is activated. This preliminary control prevents indefinite output states that would cause misprogramming during the transition to low-power mode.
Solution Approach 2:
The patent applies preliminary anti-action by preparing the control circuit to prevent misprogramming before the harmful condition occurs. The detection circuit monitors voltage status and preemptively controls the MOS transistor gate to ensure it remains non-conductive or in a known state during power transitions. This preliminary protective action counteracts the potential misprogramming that would result from timing delays during cut-off operations.
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
Prevents misprogramming of the fuse device during power source or ground state changes, ensuring accurate programming and reducing errors in LSI systems.
Implementation Method 1
the MOS transistor is made conductive by the signal obtained through the conversion, thereby performing programming
Implementation Method 2
passing a current to change a resistance value of the fuse device from a low level to a high level
Data Source
AI summary
A gate of a MOS transistor connected to a fuse device in series is controlled by an AND circuit connected to the same power source as the fuse device is connected, thereby pulling down one input of the AND circuit to a ground. Thus, misprogramming of the fuse device when an LSI power source is turned ON/OFF can be prevented.