Data Output Control Circuit for CAS Latency Phase Alignment
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Solution Overview
Problem
Semiconductor integrated circuits face limitations in operable frequency range, accuracy of phase synchronization, and layout area due to delays and PVT variations in data output control signal generation, particularly with increasing CAS latency.
Innovation Solution
A circuit and method that include a delay correction signal generator and a column address strobe latency control multiplexer to adjust and synchronize data output control signals based on phase differences between clocks and delay locked loop clocks, minimizing the need for multiple delay chains and flip-flops, and compensating for variable delays to maintain signal integrity across PVT variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple delay chains and flip-flops are used for each CAS latency to compensate for delays, then phase synchronization accuracy is improved, but device complexity and layout area increase
Solution Approach 1:
The patent implements a universal delay compensation mechanism where a single delay chain and flip-flop structure serves multiple CAS latency values. The delay compensation unit dynamically adjusts its operation based on the detected CAS latency, allowing the same hardware resources to compensate for different delay requirements (tDO + tCMD) across various CAS latency configurations, thereby reducing overall circuit complexity while maintaining phase synchronization accuracy.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities where the delay compensation unit can adaptively modify its delay characteristics based on detected CAS latency values and PVT variations. This dynamic behavior allows the circuit to optimize phase compensation in real-time without requiring dedicated static delay chains for each CAS latency, reducing device complexity while maintaining synchronization precision.
2Measurement precision
If multiple delay chains and flip-flops are used for each CAS latency to compensate for delays, then phase synchronization accuracy is improved, but layout area increases
Solution Approach 1:
The patent implements a universal delay compensation mechanism where a single delay chain and flip-flop structure serves multiple CAS latency values. The delay compensation unit dynamically adjusts its operation based on the detected CAS latency, allowing the same hardware resources to compensate for different delay requirements (tDO + tCMD) across various CAS latency configurations, thereby reducing overall circuit complexity and layout area while maintaining phase synchronization accuracy.
Solution Approach 2:
The patent merges the delay compensation functionality for multiple CAS latencies into a single shared delay chain and flip-flop structure. Instead of having separate delay chains for each CAS latency value, the patent combines them into one universal structure that can be dynamically configured, significantly reducing the total layout area required while maintaining the ability to accurately synchronize phases for different CAS latency requirements.
3Manufacturing precision
If delay chains are designed with fixed delay time, then manufacturing precision is improved, but adaptability to PVT variations deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the actual delay experienced by signals is detected and used to dynamically adjust the delay compensation amount. The delay detection unit monitors the actual delay characteristics under varying PVT conditions and feeds this information back to the delay compensation unit, which then adjusts its compensation accordingly. This closed-loop feedback system maintains both manufacturing precision and adaptability to PVT variations.
Solution Approach 2:
The patent dynamically changes the delay parameters of the delay compensation unit based on detected PVT variations and actual delay measurements. By adjusting delay cell enablement, delay tap selection, or other delay-controlling parameters in response to measured conditions, the system maintains precise phase synchronization across varying process, voltage, and temperature conditions while preserving the benefits of fixed-delay manufacturing precision.
4Reliability
If more delay compensation is applied to account for delay variations, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the actual delay experienced by signals is detected and used to dynamically adjust the delay compensation amount. The delay detection unit monitors the actual delay characteristics under varying PVT conditions and feeds this information back to the delay compensation unit, which then adjusts its compensation accordingly. This closed-loop feedback system maintains both manufacturing precision and adaptability to PVT variations.
Data Source
AI summary
The data output control signal generating circuit includes a delay correction signal generating unit that delays an input signal by a phase difference between a clock and a delay locked loop clock, and latches the delayed signal to generate a plurality of output enable signals. A column address strobe latency control multiplexer selects the output enable signal corresponding to column address strobe latency among the plurality of output enable signals, on the basis of the signal obtained by delaying the input signal by the phase difference between the clock and the delay locked loop clock, and outputs the selected signal as the data output control signal.