Internal Clock Duty Cycle Correction Under PVT Variations
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Solution Overview
Problem
Semiconductor devices face performance degradation due to distorted duty cycle ratios and changed delay times caused by environmental elements such as fabrication processes, voltage variations, and temperature, which existing internal clock signal generation circuits like DLLs struggle to compensate for effectively.
Innovation Solution
A semiconductor device with a monitoring unit that adjusts the duty cycle ratio or delay times of clock signals by using a control signal to correct distortions and changes detected after locking, incorporating a monitoring unit and a duty cycle correction unit to maintain stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional DLL is used to generate internal clock signals, then the basic clock generation function is achieved, but the duty cycle ratio becomes distorted and delay times change due to environmental elements
Solution Approach 1:
The patent implements a feedback mechanism where the monitoring unit continuously observes the control signal from the phase detection unit, and the duty cycle correction unit adjusts the clock signal based on this feedback. This closed-loop system compensates for environmental variations by using the control signal as a reference to detect and correct duty cycle distortions and delay time changes, thereby maintaining reliable clock signal generation despite environmental fluctuations.
Solution Approach 2:
The patent dynamically changes the parameters of the clock signal by adjusting the duty cycle ratio and delay times based on environmental conditions. The duty cycle correction unit modifies the control signal parameters to compensate for distortions caused by temperature, voltage, and process variations, allowing the system to adapt to changing environmental conditions while maintaining signal integrity.
2Reliability
If environmental monitoring is added to correct duty cycle ratios and delay times, then clock signal stability is improved, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by having the monitoring unit utilize the existing control signal from the phase detection unit for dual purposes: both for the normal DLL operation and for environmental element monitoring. This allows the system to perform clock generation and environmental compensation without requiring completely separate monitoring circuits, thereby improving reliability while limiting the increase in device complexity.
Solution Approach 2:
The system performs self-service by using its own internal control signal as the basis for monitoring environmental effects. The monitoring unit extracts environmental information from the control signal that is already present in the circuit, eliminating the need for external monitoring devices. This self-contained approach maintains signal stability while minimizing additional circuit complexity.
Data Source
AI summary
A semiconductor device includes: an internal clock signal generation unit configured to receive an external clock signal and to generate an internal clock signal in response to a control signal; and a monitoring unit configured to monitor environmental elements reflected in a circuit response to the control signal.