Phase Mixer Slew Rate Adjustment for Constant Phase Change
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Solution Overview
Problem
Conventional phase mixers experience increased jitter and loss of phase control precision when mixing signals with large phase differences, leading to non-constant phase change amounts in the output signal, which affects the performance of delay locked loops.
Innovation Solution
Incorporating a slew rate control unit that adjusts the slew rate at the mixing node based on the phase difference between input signals, ensuring constant phase change amounts by decreasing the slew rate when the phase difference exceeds a reference value, thereby reducing jitter and maintaining high-frequency operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the phase difference between input signals is large, then the phase mixer can handle a wider phase range, but the phase change amount becomes non-constant and jitter increases
Solution Approach 1:
The slew rate control unit dynamically adjusts the slew rate of the mixing node based on the phase difference between input signals. When the phase difference is large, the slew rate is decreased to maintain constant phase change amounts. This dynamic adjustment allows the phase mixer to adapt to different phase difference conditions while preserving measurement precision.
Solution Approach 2:
The invention changes the slew rate parameter of the mixing node in response to phase difference conditions. By controlling the slew rate (the rate of change of voltage at the mixing node), the system maintains constant phase change amounts even when mixing signals with large phase differences, thus resolving the contradiction between adaptability and precision.
2Speed
If the slew rate at the mixing node is high, then the operation speed is fast, but the phase change amount becomes non-constant when phase difference is large
Solution Approach 1:
The slew rate control unit provides dynamic control of the mixing node's voltage transition speed. Based on the detected phase difference, the control unit adjusts the slew rate in real-time, allowing high-speed operation when phase differences are small and reduced slew rate when phase differences are large, thereby maintaining phase change constancy.
Solution Approach 2:
The invention modifies the slew rate parameter conditionally based on phase difference measurements. When the phase difference exceeds a threshold, the slew rate is reduced to ensure constant phase change amounts, while allowing high slew rates when phase differences are within acceptable ranges, thus balancing speed and precision requirements.
3Device complexity
If conventional phase mixing is used without slew rate control, then the circuit is simple, but jitter increases and phase control precision is lost
Solution Approach 1:
The slew rate control unit acts as an intermediary component between the phase mixer and the output. It monitors the phase difference and controls the slew rate of the mixing node, serving as a mediator that maintains phase control precision without requiring complete redesign of the phase mixing circuitry.
Solution Approach 2:
The invention implements a feedback mechanism where the phase difference between input signals is detected and used to control the slew rate. This feedback loop ensures that the phase change amounts remain constant by adjusting the mixing node's voltage transition speed based on actual phase difference conditions, thereby maintaining reliability.
Data Source
AI summary
A phase mixer includes a first driver configured to drive a first input signal to a mixing node with a driving force determined by a first setting value, a second driver configured to drive a second input signal to the mixing node with a driving force determined by a second setting value, and a slew rate control unit configured to control a slew rate at the mixing node.