Clock Phase Shifter Using AC Waveform Deformation for 90° Output
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Solution Overview
Problem
Existing phase shifters fail to maintain a 90-degree phase difference between output signals when the duty ratio of the input clock signal deviates from 50%, particularly with waveforms like rectangular or trapezoid waves, as they struggle to adjust the duty ratio and maintain the phase difference.
Innovation Solution
A phase shifter incorporating an AC component amplifying unit with positive gain slope characteristics, which deforms the input differential clock signal to adjust the transition time between output signals, ensuring a 90-degree phase difference by attenuating signal amplitudes differently based on time length, thereby compensating for duty ratio deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional phase shifter uses a standard dividing circuit with master-slave D latches, then the circuit structure is simple, but the phase difference between output signals deviates from 90 degrees when the duty ratio of the input clock signal is not 50%
Solution Approach 1:
The patent applies preliminary action by deforming the input clock signal waveform before it reaches the dividing circuit. The AC component amplifying unit pre-adjusts the signal characteristics (amplifying AC components and attenuating DC components) so that when the standard dividing circuit processes this pre-deformed signal, the output phase difference is corrected to exactly 90 degrees. This allows the use of a simple standard dividing circuit structure while achieving high phase difference accuracy.
Solution Approach 2:
The patent introduces an AC component amplifying unit as an intermediary between the input clock signal and the dividing circuit. This intermediary unit transforms the input signal by amplifying its AC components and attenuating DC components, creating a deformed clock signal that enables the subsequent dividing circuit to produce accurate 90-degree phase differences even when the original input had non-50% duty ratio.
2Adaptability or versatility
If the phase shifter processes rectangular or trapezoid waveforms with duty ratio deviation, then it can handle practical signal types, but the phase difference control becomes inaccurate
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the amplitude parameters of the clock signal through the AC component amplifying unit. It changes the relative amplitudes of different frequency components (amplifying AC, attenuating DC) based on the input signal characteristics, thereby adapting the signal parameters to ensure that the dividing circuit produces accurate 90-degree phase differences regardless of whether the input is rectangular, trapezoid, or other practical waveform types.
3Manufacturing precision
If the phase shifter uses duty ratio adjustment to maintain 90-degree phase difference, then phase accuracy is improved, but the adjustment mechanism increases device complexity
Solution Approach 1:
The patent replaces mechanical duty ratio adjustment mechanisms with an electronic signal processing approach. Instead of physically adjusting duty ratio through complex switching or timing control circuits, it uses an AC component amplifying unit that electronically transforms the signal waveform by selective amplification and attenuation of frequency components, achieving phase difference correction through signal processing rather than mechanical adjustment.
Data Source
AI summary
A phase shifter according to an embodiment of the present invention includes: an AC component amplifying unit; and a dividing circuit. The AC component amplifying unit has positive gain slope characteristics and deforms a waveform of an input differential clock signal to output the deformed differential clock signal. The dividing circuit includes a T-flipflop having two D latches connected in series and receives the deformed differential clock signal defoemed by the AC component amplifying unit to generate at least two output signals having a phase difference of 90 degrees with a frequency of ½ of the deformed differential clock signal.