Duty-Cycle Corrector Circuit for Constant Delay Clock Synchronization
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Solution Overview
Problem
Existing duty-cycle correctors fail to address the duty cycle of a clock signal in a clock signal in a clock signal in a clock signal in a clock signal in a high-speed circuit, particularly in serializer/deserializer systems, due to variations in process, voltage, and temperature, leading to timing synchronization issues and rising edge delays.
Innovation Solution
A duty-cycle corrector circuit comprising a divider stage, frequency trimming stage, voltage control stage, and logic stage, which adjusts the duty cycle of an input clock signal to 50% by dividing, delaying, and performing logic operations on clock signals to generate an output clock signal with precise timing synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing duty-cycle correctors are used to adjust the duty cycle to 50%, then the duty cycle is corrected, but timing synchronization issues occur due to rising edge variations
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the rising edge timing before the duty cycle correction process. The circuit modifies the rising edge delay characteristics in advance through controlled delay elements, ensuring that timing synchronization is maintained throughout the duty cycle adjustment process. This prevents timing synchronization issues from occurring during operation.
2Manufacturing precision
If duty cycle adjustment is performed in high-speed circuits, then the duty cycle varies due to PVT variations, but rising edge delays increase causing synchronization problems
Solution Approach 1:
The patent implements feedback mechanisms that continuously monitor the rising edge delay and duty cycle characteristics. Based on this feedback, the circuit dynamically adjusts the delay elements to compensate for PVT variations. This ensures that rising edge delays are minimized while maintaining stable duty cycle correction across varying process, voltage, and temperature conditions.
Solution Approach 2:
The circuit employs dynamic delay elements that can adjust their delay characteristics in real-time based on operating conditions. These dynamic elements respond to PVT variations by automatically modifying their delay properties, thereby maintaining optimal rising edge timing and duty cycle accuracy without introducing additional delays.
3Measurement precision
If precise clock phase is needed for timing synchronization in Serdes systems, then duty cycle must be precisely controlled, but existing correctors cannot effectively address rising edge delay differences
Solution Approach 1:
The patent applies local quality by implementing separate control mechanisms for different aspects of clock signal characteristics. Specifically, the circuit independently controls the rising edge delay characteristics while maintaining overall duty cycle precision. This localized control allows precise adjustment of rising edge timing without affecting the overall clock phase accuracy required for Serdes timing synchronization.
Data Source
AI summary
The present disclosure provides an integrated circuit, which includes a divider stage, a frequency trimming stage, a voltage control stage, and a logic stage. The divider stage is configured to generate a first clock signal by dividing a frequency of an input clock signal. The frequency trimming stage is configured to add a first delay to the first clock signal to generate a second clock signal. The voltage control stage is configured to repeatedly adjust a second delay of the second clock signal according to a control signal generated by a feedback path to generate a third clock signal. The logic stage is configured to perform a logic operation according to the first clock signal and the third clock signal to generate an output clock signal.