Resonant Clock Network Switching for Smooth Mode Transitions

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Solution Overview

Problem

Resonant clocking in integrated circuits is inefficient at a wide range of frequencies, leading to malformed clock waveforms and power consumption issues due to abrupt loading and voltage overshoot during mode transitions, which affect processor operation and longevity.

Innovation Solution

Implementing a switch bank with control logic to stagger the turn-on and turn-off of inductors in the clock network, allowing for gradual energy coupling and decoupling, thereby maintaining clock waveform integrity and reducing current demand and voltage overshoot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If resonant clocking is implemented to reduce power consumption, then power consumption is reduced, but clock waveform integrity degrades at frequencies away from resonant frequency

Engineering Contradiction:
Improvepower consumptionVSAvoidclock waveform integrity
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The system dynamically switches between resonant and conventional clocking modes based on operating frequency. A frequency detector monitors the clock frequency and control logic transitions the clock network between modes, allowing the system to adapt to different frequency requirements while maintaining power efficiency when resonant clocking is applicable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the clock network by adjusting the resonant tank circuit configuration. When operating near resonant frequency, the resonant tank is activated to achieve power savings. When frequency deviates, the system transitions to conventional clocking, effectively changing the operational mode to maintain waveform integrity.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If abrupt mode transition is implemented for simplicity, then device complexity is reduced, but voltage overshoot and current demand increase

Engineering Contradiction:
Improvecontrol logic complexityVSAvoidvoltage overshoot
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The control logic prepares for mode transition by detecting frequency conditions in advance and initiating the transition sequence before abrupt changes occur. The frequency detector continuously monitors and triggers transition sequences that include gradual engagement of resonant tank components, preventing sudden voltage overshoot and current demand spikes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates protective measures before transition occurs by using controlled switching sequences. The resonant tank circuit is engaged or disengaged through staged switching of capacitors and inductors, cushioning the transition to prevent harmful voltage overshoot and current spikes that would occur with abrupt switching.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If single switch is used for mode transition, then device complexity is reduced, but transition reliability decreases due to voltage overshoot

Engineering Contradiction:
Improveswitch bank complexityVSAvoidtransition reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The switching function is segmented into multiple switches arranged in a switch bank, where each switch controls a specific capacitor or inductor in the resonant tank circuit. This segmentation allows staged engagement of resonant components, enabling controlled energy transfer that prevents voltage overshoot and improves transition reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The switch bank acts as an intermediary mechanism between the conventional clocking mode and resonant clocking mode. By using multiple switches to progressively engage or disengage resonant tank components, the system mediates the transition smoothly, preventing direct abrupt connections that cause voltage overshoot and reliability issues.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables seamless transitions between resonant and conventional clocking modes without degrading clock waveforms, reducing power consumption, and addressing reliability concerns by spreading current draw and controlling voltage transitions.

Implementation Method 1

the capacitor circuit 107 and the inductor 101 form a resonant tank

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2891026B1Transitioning between resonant clocking mode and conventional clocking mode
Publication Date: 2016.06.22 ADVANCED MICRO DEVICES INC
  • EP2891026B1 patent drawingFigure 1A~1B
  • EP2891026B1 patent drawingFigure 2
  • EP2891026B1 patent drawingFigure 3

AI summary

A resonant clock network includes an inductor coupled to the clock network through a plurality of switches. When the clock network enters resonant mode, the turn-on of the switches to couple the inductor to the clock network is staggered. The clock network may be formed of multiple regions, each with its own inductor and switches. The turn-on of switches of each region may be staggered with respect to the turn-on off the switches of the other regions as well as to the turn-on of switches within a region. In addition to staggering the turn-on of the switches when entering the resonant mode, the switches may be turned off in a staggered manner when exiting the resonant mode of operation.