Internal Clock Pulse Control with Fuse-Selectable Delay Cells
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Solution Overview
Problem
Conventional pulse control devices in DRAMs experience varying pulse widths due to changes in process conditions and temperature, leading to operational inconsistencies and potential errors in data transmission.
Innovation Solution
A pulse control device with a fuse set and mode register that selectively outputs delay increase and decrease signals to adjust the number of delay cells, maintaining a constant pulse width by programming the fuse or mode register based on process conditions and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pulse width is determined by fixed delay cells, then the circuit structure is simple, but the pulse width varies with process and temperature changes
Solution Approach 1:
The patent implements dynamic adjustment of delay cell quantity through fuse set and mode register set configurations. The delay cell quantity is no longer fixed but can be dynamically selected based on process conditions and temperature, allowing the circuit to adapt and maintain consistent pulse width across varying operating conditions.
Solution Approach 2:
The patent changes the parameter of delay cell quantity to compensate for process and temperature variations. By programmatically selecting different numbers of delay cells through fuse or mode register configurations, the system adjusts the total delay to maintain constant pulse width despite environmental changes.
2Reliability
If the number of delay cells is increased to compensate for process variation, then the pulse width consistency improves, but the device complexity increases
Solution Approach 1:
The patent segments the delay function into multiple individual delay cells that can be independently selected and configured. This segmentation allows flexible combination of delay cells to achieve the desired total delay, enabling precise adjustment without requiring a completely different circuit design for each condition.
Solution Approach 2:
The patent creates a universal delay structure where the same delay cell design can be used in different quantities and configurations to handle various process conditions and temperature ranges. The fuse set and mode register set provide a universal control mechanism that works across all operating conditions without requiring separate dedicated circuits.
3Ease of manufacture
If fixed delay values are used, then the manufacturing process is simple, but the pulse width varies under different temperature conditions
Solution Approach 1:
The patent performs preliminary configuration through fuse cutting or mode register programming during manufacturing or initialization. This preliminary action sets the appropriate delay cell quantity for the specific process conditions before the device enters normal operation, ensuring temperature compensation is already in place without requiring real-time adjustment during operation.
Data Source
AI summary
A pulse control device is maintained with a constant pulse width corresponding to a change of process or temperature. The pulse control device comprises a fuse set for selectively outputting a delay increase signal and a delay decrease signal that have a different state based on a cutting or non-cutting state of a fuse on which information on a change of process is programmed, and a pulse generator provided with a plurality of delay cells with predetermined time delay for selectively increasing or decreasing the number of the plurality of delay cells depending on the delay increase signal and the delay decrease signal to generate an internal clock with a pulse width corresponding to the number of the increased or decreased delay cells.