Pulse Width Control Using Selectable Delay Cells
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Solution Overview
Problem
Conventional pulse control devices in DRAMs generate pulses with varying widths due to changes in process conditions and temperature, leading to operational inconsistencies and 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 and temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pulse control devices generate pulses based on external clock without adjustment, then the device structure remains simple, but the pulse width varies with process and temperature changes causing operational errors
Solution Approach 1:
The pulse control device dynamically adjusts the number of delay cells in the delay path based on temperature and process conditions. The controller activates or deactivates specific delay cells to maintain constant pulse width despite environmental variations, transforming a static circuit into a dynamically adaptable system.
Solution Approach 2:
The invention changes the delay parameter by selectively controlling the number of active delay cells. By adjusting the delay path length through controller signals, the system compensates for process and temperature variations, maintaining consistent pulse width across different operating conditions.
2Manufacturing precision
If the number of delay cells is increased to compensate for process variations, then the pulse width stability improves, but the device complexity and area increase
Solution Approach 1:
The delay path is segmented into multiple individual delay cells that can be independently controlled. This segmentation allows the system to selectively activate only the necessary number of cells required for compensation, rather than requiring all cells to be always active, thus reducing the effective complexity while maintaining precision.
Solution Approach 2:
The system dynamically configures the delay path by activating or deactivating specific delay cells based on measured process and temperature conditions. This dynamic reconfiguration allows precise pulse width control without permanently requiring the maximum number of delay cells, optimizing the balance between precision and complexity.
3Reliability
If delay cells are selectively activated to maintain constant pulse width, then operational reliability improves, but the control logic complexity increases
Solution Approach 1:
The invention replaces complex mechanical or manual adjustment mechanisms with an electronic control system. The controller uses electrical signals to selectively activate delay cells, substituting what would otherwise require physical reconfiguration with a simpler electronic switching mechanism controlled by logic circuits.
Solution Approach 2:
The control system incorporates feedback from temperature sensors and process condition detectors to automatically adjust the number of active delay cells. This closed-loop feedback mechanism simplifies the control logic by using measured conditions to directly determine the required delay configuration, rather than requiring complex predictive algorithms.
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.