Low-Power Clock Repeaters with Active Guard Rings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing clock distribution systems in high-frequency applications face significant challenges with injection locking issues due to electric and magnetic couplings, leading to unacceptable jitter and duty cycle distortions, which are difficult to address effectively without increasing circuit complexity and power consumption.
Innovation Solution
The implementation of low-power, actively shielded passive clock repeaters with resonant RLC networks and active guard rings to provide voltage gain while protecting against injection locking effects, using differential-mode circuits and programmable offset frequencies to shift undesired frequencies out of the locking range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple clock drivers are distributed along the clocking path to drive all clock signal loads, then clock signal distribution coverage is improved, but injection locking interference between clock drivers increases
Solution Approach 1:
The patent introduces guard rings as intermediary shielding structures between adjacent clock drivers. These guard rings act as mediators that intercept and redirect electric and magnetic field lines, preventing direct coupling between clock drivers. The guard rings are connected to appropriate voltage potentials (ground or supply voltage) to create equipotential barriers that block the harmful electromagnetic coupling paths.
Solution Approach 2:
The patent extracts and isolates the harmful electromagnetic fields by using guard rings to separate the electric and magnetic coupling paths between adjacent clock drivers. By physically separating the field interaction paths through shielding structures, the harmful injection locking effects are extracted from the system while maintaining the necessary clock signal distribution.
2Reliability
If dedicated circuitry is used to detect and correct injection locking effects, then injection locking protection is improved, but circuit complexity and power consumption increase
Solution Approach 1:
The patent converts the harmful electromagnetic fields that cause injection locking into beneficial shielding effects. By strategically placing guard rings and utilizing the natural electromagnetic field interactions, the design transforms potential harmful couplings into protective shielding mechanisms. The guard rings utilize the same electromagnetic principles that cause the problem to create protective barriers.
Solution Approach 2:
The guard ring structure provides self-service protection against injection locking without requiring external detection or correction circuitry. The shielding effect is automatically present whenever the guard rings are properly biased, eliminating the need for additional active components, control logic, or power-consuming correction mechanisms.
3Object-affected harmful factors
If PLL isolation techniques are used to reduce coupling between PLLs, then injection locking risk is reduced, but isolation effectiveness decreases as device dimensions shrink
Solution Approach 1:
The patent applies local quality enhancement by placing guard rings specifically at critical locations where electromagnetic coupling occurs between adjacent clock drivers. Rather than attempting global isolation, the guard rings provide localized shielding precisely where the harmful coupling paths exist, maintaining effectiveness even in scaled-down device dimensions.
Solution Approach 2:
The patent changes the electromagnetic field distribution parameters by introducing guard rings with specific voltage biases. By adjusting the potential of the guard rings relative to the clock drivers, the electromagnetic field paths are fundamentally altered, creating regions of reduced coupling that maintain isolation effectiveness independent of device scaling.
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 reduces power consumption and effectively mitigates injection locking interference, maintaining sufficient voltage swing and reducing jitter, while maintaining low power consumption and circuit simplicity.
Implementation Method 1
passive clock repeaters with resonant RLC networks
Implementation Method 2
programmmable offset frequencies to shift undesired frequencies out of the locking range
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A low power clock distribution circuit system (200) includes a clock generator (201) for generating a high frequency clock signal that is supplied to a clock interconnect running to multiple lanes of an integrated circuit, each lane including a passive clock repeater circuit (e.g., 203) having a differential-mode RLC network (e.g., 301) that is shielded by an active guard ring structure (e.g., 511) and that is coupled to receive first and second input clock signals (Vip, Vin) to provide clock signal gain boosting at a predetermined frequency range and clock signal attenuation out of the operating frequency range, thereby generating the first and second output clock signals (Vop, Von) that are provided to a clocked circuit (e.g., 211).