Antifuse OTP Memory Program Control Circuit
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Solution Overview
Problem
Existing antifuse-type one-time programming (OTP) memory cell arrays face challenges in accurately programming memory cells due to variations in semiconductor chip processes, leading to inconsistent program voltages and currents, which can result in over-programming or under-programming of memory cells.
Innovation Solution
A program control circuit is introduced that monitors the program current from the OTP memory cell in real-time and adjusts the program voltage accordingly. The circuit includes a program voltage generator, a proportional current generator, a detection circuit, and a current mirror to ensure that the program current is sufficient before confirming the completion of the program action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional antifuse-type OTP memory cell array is programmed without real-time monitoring, then the programming process is simple and fast, but the program voltage and current are inconsistent due to semiconductor chip process variations, leading to over-programming or under-programming
Solution Approach 1:
The patent implements real-time monitoring of the program current through a detection circuit that provides feedback to the program control circuit. This feedback mechanism allows the control circuit to adjust the program voltage dynamically based on the actual current flowing through the memory cell, ensuring consistent programming despite process variations. The feedback loop includes a current detection circuit, a comparison circuit, and a voltage adjustment mechanism that operates during the programming sequence.
Solution Approach 2:
The patent dynamically changes the program voltage parameter during the programming process based on real-time current monitoring. The control circuit adjusts the voltage level in response to detected current characteristics, transitioning from a fixed voltage approach to a variable voltage approach. This parameter change enables the system to compensate for manufacturing variations and achieve precise programming control.
2Manufacturing precision
If real-time monitoring of program current is implemented, then programming precision is improved, but the programming time and energy consumption increase
Solution Approach 1:
The feedback mechanism enables the control circuit to detect when the programming condition is satisfied and terminate the programming sequence early, avoiding unnecessary time consumption. Instead of using a fixed long programming duration, the system monitors current in real-time and stops when the target is achieved, reducing average programming time while maintaining precision.
Solution Approach 2:
The detection circuit and control logic are prepared in advance during the programming sequence initialization. The monitoring function is established before the actual programming begins, allowing immediate detection and response without adding significant overhead time. The preliminary setup includes configuring the detection circuit and establishing the feedback loop, which then operates efficiently during the programming process.
3Reliability
If fixed program voltage is used without adjustment, then the control circuit is simple, but the programming reliability is low due to process variations in semiconductor chips
Solution Approach 1:
The feedback mechanism provides continuous monitoring of the program current and dynamically adjusts the program voltage to maintain optimal programming conditions. This closed-loop control ensures that even with process variations, the programming remains reliable by adapting to actual cell characteristics. The feedback path includes current detection, comparison with reference values, and voltage adjustment based on the comparison results.
Solution Approach 2:
The patent transitions from a static fixed voltage approach to a dynamic variable voltage approach. The program voltage is no longer fixed but changes in real-time based on the programming progress and detected current characteristics. This dynamic adjustment allows the system to handle process variations and achieve reliable programming across different manufacturing batches.
Data Source
Figure 1A~3
Figure 4A
Figure 4B
AI summary
A program control circuit for an antifuse-type one time programming memory cell array is provided. When the program action is performed, the program control circuit monitors the program current from the memory cell in real time and increases the program voltage at proper time. When the program control circuit judges that the program current generated by the memory cell is sufficient, the program control circuit confirms that the program action is completed.