Differential Duty Cycle Correction Circuit for Phase Error Control
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Solution Overview
Problem
Conventional RF circuits that use buffers to communicate differential signals over large distances often diminish performance and signal quality.
Innovation Solution
A duty cycle correction (DCC) circuit with an analog feedback loop that includes a differential signal inverter circuit and a feedback circuit, utilizing transconductance amplifiers and low pass filters to equalize duty cycles and reduce phase errors in differential signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If buffers are used to communicate differential signals over large distances, then signal transmission capability is improved, but signal quality and performance deteriorate due to duty cycle errors and phase noise
Solution Approach 1:
The patent implements an analog feedback loop that continuously monitors the duty cycle of differential signals and provides corrective feedback to equalize duty cycle errors. The feedback circuit measures the duty cycle difference between complementary signals and adjusts the buffer stages accordingly, thereby maintaining signal quality over large transmission distances without sacrificing performance
Solution Approach 2:
The patent dynamically adjusts transistor biasing parameters and operating points within the buffer stages to compensate for duty cycle errors. By changing the electrical parameters of the buffer circuitry based on detected signal conditions, the system maintains optimal signal quality while transmitting over long distances
2Length of moving object
If multiple buffer stages are used to extend signal range, then transmission distance is improved, but phase noise and duty cycle errors increase
Solution Approach 1:
The analog feedback loop specifically targets and corrects phase noise accumulation in multi-stage buffers by continuously monitoring and equalizing the phase relationships between differential signals. The feedback mechanism detects phase deviations introduced by each buffer stage and applies corrective adjustments to maintain coherent signal transmission
Solution Approach 2:
The circuit performs preliminary duty cycle equalization at each buffer stage before signals are passed to the next stage. By proactively correcting duty cycle errors and phase noise at the source rather than allowing them to accumulate, the system maintains reliable transmission over extended distances with multiple buffer stages
Data Source
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AI summary
A duty cycle correction (DCC) circuit (100) for use in relation to differential signal communications, a method of providing duty cycle correction, and communications systems and methods employing same, are disclosed herein. In one example embodiment, the circuit (100) includes a differential signal inverter circuit (110, 112) including first and second inverter circuits (132, 134), each of which has a respective inverter and respective first and second transistor devices (134, 136) respectively coupled between the respective inverter and first and second voltages (138, 140), respectively. The circuit also includes a feedback circuit (111) coupled to respective output ports (106, 108) of the respective first and second inverter circuits and also to respective feedback input ports (A, B, C, D) of the respective transistor devices (134, 136). The feedback circuit operates to provide one or more feedback signals (A, B, C, D) causing one or more of the transistor devices to perform current limiting. Respective duty cycles of output signals respectively are equal or substantially equal based on the current limiting.