Fuse Read Stabilization Circuit for Signal Oscillation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In integrated circuits, parasitic capacitance causes instability and oscillation in output signals generated by sense amplifiers due to electrical fuses, leading to incorrect read signals during programming operations.
Innovation Solution
The implementation of a stabilization circuit, including an inverter and an NMOS transistor, coupled to the output node of the sense circuit, which stabilizes the voltage and prevents oscillation by pulling the node down to ground, and alternative stabilization circuits using capacitive units or pull-up transistors to sustain or raise the voltage of operation nodes during read operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sense amplifier is used to detect sensing current during fuse read operations, then the read operation can be performed, but parasitic capacitance causes the output signal to oscillate and become unstable
Solution Approach 1:
A stabilization circuit is introduced as an intermediary component between the sense amplifier output and the read operation. This stabilization circuit includes a first NMOS transistor with its gate connected to a control node, drain connected to the sense amplifier output, and source connected to ground. The stabilization circuit acts as a mediator that filters out the oscillations caused by parasitic capacitance while preserving the valid signal, thereby resolving the contradiction between enabling read operations and eliminating harmful parasitic effects.
Solution Approach 2:
The harmful oscillation component is extracted and separated from the valid signal through the stabilization circuit. By using the NMOS transistor as a switch controlled by the control node, the circuit selectively removes the high-frequency oscillations generated by parasitic capacitance while maintaining the lower-frequency valid read signal, thus extracting the harmful factor from the system.
2Measurement precision
If the sense amplifier generates output signal during read operation, then fuse state can be detected, but the output signal becomes incorrect due to oscillation
Solution Approach 1:
The stabilization circuit serves as an intermediary filtering stage that processes the sense amplifier output before it is used for fuse state detection. The NMOS transistor in the stabilization circuit, controlled by the control node, selectively passes or blocks signal components based on their frequency characteristics, ensuring that only valid signal components reach the detection stage, thereby improving both measurement precision and output signal correctness.
Data Source
AI summary
A circuit includes a fuse cell, a sense circuit and an output control circuit. The fuse cell includes an electrical fuse. The sense circuit is electrically coupled to the fuse cell and configured for generating a sense signal indicative of a programmed condition of the electrical fuse, at an output of the sense circuit. The output control circuit is electrically coupled to the output of the sense circuit, and the output control circuit is configured for latching the sense signal indicative of the electrical fuse having been programmed, during a read operation of the fuse cell.