Multi-Phase Clock Interpolation Using Segmented Current Branches
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Solution Overview
Problem
Existing phase interpolation devices face challenges in generating phase clocks with high linearity due to process variations, voltage drift, and temperature changes, affecting the accuracy of phase time differences between interpolated clocks.
Innovation Solution
A phase interpolation device comprising a digital controller circuit and a phase interpolator with multiple circuit branches, each including current sources and a capacitor, controlled to charge and discharge the capacitor differently based on input clock edges, ensuring high linearity in generating N phase clocks between two input clocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional phase interpolation methods are used, then the device complexity is low, but the manufacturing precision of phase time difference deteriorates due to process variations, voltage drift, and temperature changes
Solution Approach 1:
The phase interpolator is divided into multiple circuit branches (first circuit branch, second circuit branch, etc.), each handling specific current sources for charging/discharging the capacitor. This segmentation allows precise control of charge/discharge currents to achieve linear phase interpolation while compensating for process variations and temperature effects.
Solution Approach 2:
The invention dynamically changes the number of current sources used for charging versus discharging the capacitor based on the desired phase output. By adjusting these parameters (current source count, charge/discharge duration), the system achieves high-precision phase time difference control that compensates for environmental variations.
2Manufacturing precision
If the number of circuit branches is increased to N×M, then the manufacturing precision of phase clocks improves, but the device complexity and quantity of current sources increases
Solution Approach 1:
Each current source in the circuit branches is designed to serve multiple functions: they can charge the capacitor, discharge the capacitor, and be selectively activated based on the required phase output. This multi-functionality allows N×M current sources to precisely control N phase clocks with high linearity while managing the complexity through unified control logic.
Solution Approach 2:
The system dynamically selects and activates specific current sources from the N×M available sources based on the desired phase output. The digital controller circuit adjusts which current sources are active at any given time, enabling precise phase interpolation while efficiently utilizing the available current sources to manage complexity.
3Productivity
If asymmetric charge and discharge currents are used, then the productivity of phase clock generation improves with high linearity, but the device complexity increases due to different current source requirements
Solution Approach 1:
The phase interpolator uses periodic charging and discharging of the capacitor with asymmetric current sources. The digital controller circuit periodically activates specific current sources to charge the capacitor during certain phases and discharge it during others, creating the interpolated phase clocks with high linearity and efficient generation speed.
Solution Approach 2:
The system dynamically configures which current sources are used for charging versus discharging based on the desired phase output. This dynamic configuration allows asymmetric current profiles that optimize phase clock generation efficiency and linearity while the digital controller manages the complexity of coordinating multiple current sources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the generation of phase clocks with high linearity by precisely controlling the charging and discharging of capacitors through the digital controller circuit, effectively mitigating the impact of process variations and temperature changes, thereby improving the accuracy of phase time differences.
Implementation Method 1
the phase interpolator further includes a capacitor electrically coupled between the output node and the ground voltage
Implementation Method 2
Each of the plurality of circuit branches includes a first current source and a second current source electrically coupled in series between a supply voltage and a ground voltage
Data Source
AI summary
A phase interpolation device and a multi-phase clock generation device are provided. The phase interpolation device includes a digital controller circuit and a phase interpolator that includes a capacitor and circuit branches, which are controlled by the digital controller circuit to generate an n-th phase clock of N phase clocks between first and second input clocks. When the n-th phase clock is generated, the digital controller circuit controls, in response to appearances of rising edges of the first input clock, the circuit branches to charge the capacitor using (N−n+1)×M ones of the first current source, and controls, in response to appearances of rising edges of the second input clock, the circuit branches to use N×M ones of the first current source to charge the capacitor. N, M, n are integers.