Ring-Oscillator Frequency Divider With Switchable Division Ratios
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Solution Overview
Problem
Conventional injection-locked frequency dividers used as prescalers in phase-locked loop-based frequency synthesizers face challenges such as limited operating ranges, high power consumption, and the inability to dynamically switch between multiple division ratios, leading to trade-offs in design footprint and tuning resolution.
Innovation Solution
The implementation of a multiple-moduli prescaler based on an injection-locked ring-oscillator divider, which allows for dynamically changeable division ratios, reduced power consumption, and a compact design by tuning the ring oscillator's free-running frequency and switching stages to achieve multiple integer-valued moduli.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional injection-locked frequency dividers are used as prescalers, then the design footprint is reduced, but the power consumption increases and the ability to dynamically switch between multiple division ratios is lost
Solution Approach 1:
The patent implements dynamic switching between multiple division ratios (e.g., 1:2, 1:3, 1:4) by dynamically reconfiguring the ring oscillator stages. Switches control the connection of oscillator stages to achieve different effective division ratios, allowing the prescaler to adapt to different frequency synthesis requirements while maintaining low power consumption and small footprint.
Solution Approach 2:
The ring oscillator-based prescaler is designed to perform multiple division functions (dividing by 2, 3, 4, or other integers) using the same hardware structure. By selectively enabling different oscillator stages and control logic, a single device provides multiple moduli, eliminating the need for separate dividers for each ratio and thereby reducing overall power consumption and footprint.
2Area of stationary object
If conventional injection-locked frequency dividers are used, then the structure is compact, but the operating range is limited and dynamic switching between division ratios is not possible
Solution Approach 1:
The patent employs dynamic reconfiguration of the ring oscillator stages through control switches. By selectively connecting or disconnecting oscillator stages based on the desired division ratio, the prescaler can dynamically switch between multiple moduli (e.g., 1:2, 1:3, 1:4) without changing the physical structure, thereby achieving both compactness and adaptability.
Solution Approach 2:
The ring oscillator is divided into multiple selectable stages, each capable of being individually controlled. This segmentation allows different combinations of stages to be activated to achieve different division ratios, providing dynamic switching capability while maintaining a compact integrated structure.
3Device complexity
If the division ratio is fixed in conventional prescalers, then the design is simpler, but the tuning resolution and flexibility are reduced
Solution Approach 1:
The prescaler implements dynamic division ratio switching that enables fine-tuning of the output frequency. By selectively switching between different moduli (e.g., 1:2, 1:3, 1:4) based on control signals, the system achieves higher tuning resolution and flexibility while managing design complexity through systematic control logic.
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
This solution enables frequency synthesizers to operate with low power consumption, enhanced lock range, and a small footprint, allowing for dynamic switching of division ratios, thereby improving tuning resolution and reducing design complexity.
Implementation Method 1
tuning the ring oscillator's free-running frequency
Implementation Method 2
injection-locked ring-oscillator divider
Data Source
AI summary
The present disclosure includes a frequency divider circuit that includes a superharmonically injection-locked ring oscillator, injection circuitry, and various switches. The input can include a collection of signal components at different phases that are all at the same, but changeable, frequency. The divider's division ratio can be changed during the divider's operation by, for example, utilizing one or more switches to change: the number of stages in the ring oscillator, and/or which stage(s) of the ring oscillator are injected into by which input signal components.