Switchable Decoupling Capacitors for SOC Power Management

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Solution Overview

Problem

The increasing demand for processing capability in mobile devices necessitates effective power management systems to reduce power consumption and conserve battery life, while existing decoupling capacitors occupy significant surface area and cause transient voltage variations during circuit mode transitions.

Innovation Solution

An integrated circuit with a decoupling capacitor that can be switched between two voltage sources, controlled by a controller to maintain stable voltage levels by providing instantaneous current during mode transitions, thereby reducing surface area requirements and voltage fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If decoupling capacitors are used to supply instantaneous current to transitioning circuits, then transient voltage levels are maintained, but surface area occupied on the SOC increases considerably

Engineering Contradiction:
Improvetransient voltage level stabilityVSAvoidsurface area on SOC
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines multiple decoupling capacitors into a single shared capacitor that serves multiple voltage domains. The capacitor is coupled to multiple voltage sources through switch circuits, allowing one capacitor to provide decoupling functionality for several different circuits, thereby reducing the total surface area required while maintaining transient voltage stability across all domains.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The decoupling capacitor is designed to perform multiple functions across different voltage domains. By being switchably coupled to multiple voltage sources, a single capacitor provides decoupling support for various circuits transitioning between sleep and active modes, making the component universal rather than dedicated to a single function or domain.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If circuits operate in low power or sleep mode to reduce power consumption, then battery life is conserved, but transient voltage levels are adversely affected during mode transitions

Engineering Contradiction:
Improvepower consumptionVSAvoidtransient voltage level stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The decoupling capacitor is pre-charged from voltage sources before circuits transition from sleep to active mode. The switch circuits are configured to connect the capacitor to voltage sources in advance, ensuring that when a circuit needs instantaneous current during mode transition, the capacitor is already charged and ready to supply the required current, thus maintaining voltage stability without increasing power consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The decoupling capacitor acts as an intermediary energy storage element between the voltage sources and the transitioning circuits. During mode transitions, the capacitor mediates the current demand by supplying instantaneous current to the transitioning circuit, preventing direct current draws from affecting other circuits on the SOC, thus maintaining stable transient voltage levels while circuits can safely operate in low power modes.

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

The solution effectively reduces surface area usage and minimizes transient voltage variations by sharing a decoupling capacitor across multiple voltage domains, enhancing power management efficiency in mobile devices.

Implementation Method 1

a decoupling capacitor, and a controller configured to switch the decoupling capacitor between the first and second voltage source

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3132327B1Switchable decoupling capacitors
Publication Date: 2019.08.14 QUALCOMM INC
  • EP3132327B1 patent drawingFigure 1
  • EP3132327B1 patent drawingFigure 2
  • EP3132327B1 patent drawingFigure 3A~3B

AI summary

Aspects of an integrated circuit are disclosed. The integrated circuit includes a first circuit configured to be powered by a first voltage source, a second circuit configured to be powered by a second voltage source, a decoupling capacitor, and a controller configured to switch the decoupling capacitor between the first and second voltage source.