Duty Cycle Correction Circuit for Irregular Data and Clock Signals

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Solution Overview

Problem

Conventional duty cycle correctors are limited in correcting duty cycles of both clock signals with regularly iterated pulses and data signals with irregular pulses, particularly in high-speed communications systems, and cannot maintain a predetermined duty cycle for data signals transferred in a digital manner.

Innovation Solution

A duty cycle correcting device and method that includes a pulse width adjusting unit, a comparison unit, and a control unit, which adjusts and compares the pulse width of input signals with reference voltages to select optimal pulse width control codes, ensuring a duty cycle of 50% by calculating probability density functions and cumulative distribution functions based on comparison data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional duty cycle corrector is used, then the duty cycle of clock signals with regularly iterated pulses can be corrected, but it cannot correct duty cycles of data signals with irregular pulses

Engineering Contradiction:

Improvecapability to correct duty cycleVSAvoidduty cycle accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The duty cycle corrector is designed to handle both clock signals with regularly iterated pulses and data signals with irregular pulses using a unified correction mechanism. The device measures pulse widths and adjusts them accordingly, making it universally applicable to different signal types without requiring separate correction circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If the pulse width is adjusted to correct duty cycle, then the duty cycle accuracy is improved, but jitter noise increases

Engineering Contradiction:

Improveduty cycle precisionVSAvoidjitter noise

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The duty cycle corrector employs feedback mechanisms where the measured pulse width information is used to adjust subsequent pulse widths. By continuously monitoring and adjusting based on actual measurements, the system achieves precise duty cycle control while minimizing jitter through adaptive correction rather than fixed adjustments.

Inventive Principle:

Principle #23Feedback

3Reliability

If a duty cycle corrector is added to the receiver, then the bit error rate is reduced, but the device complexity increases

Engineering Contradiction:

Improvebit error rateVSAvoidreceiver structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The duty cycle corrector is integrated into the existing receiver structure, combining multiple functions including pulse width measurement, duty cycle correction, and signal processing in a unified device. This merging approach reduces the overall complexity compared to having separate dedicated circuits for each function.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8923462B2Device and method for correcting duty cycle, and receiver including the same

Publication Date: 2014.12.30 IND ACADEMIC COOP FOUND YONSEI UNIV

AI summary

A duty cycle correcting device is provided which includes a pulse width adjusting unit which adjusts a pulse width of an input signal according to a pulse width control code; a comparison unit which compares an output signal of the pulse width control unit with a plurality of reference voltages; and a control unit which selects one of a plurality of pulse width control codes based on comparison data from the comparison unit and provides the selected pulse width control code to the pulse width adjusting unit.