Capacitive DC Power Transformer for Low Ripple Conversion

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Solution Overview

Problem

Portable computing devices face limitations in mobility time due to limited battery capacity and inefficient power regulators, which restrict LCD panel size/resolution and computing performance, and often lead to thermal issues in fan-less devices.

Innovation Solution

A switched capacitor power converter using a plurality of flying capacitors and switches to dynamically rearrange their configuration through various operation phases, reducing input current ripple and enabling efficient voltage conversion for noise-sensitive applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If inductor-based switching buck converters are used to convert power efficiently, then power conversion efficiency is improved, but input current ripple and electromagnetic noise increase which affects noise-sensitive applications

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidinput current ripple and electromagnetic noise

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the inductor-based magnetic energy storage mechanism with a capacitor-based electric field energy storage mechanism. The switched capacitor converter uses capacitors to store and transfer energy during switching cycles, eliminating the inductor component that generates electromagnetic noise and current ripple, while maintaining efficient power conversion through capacitive energy transfer.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental energy storage parameter from magnetic inductance to electric capacitance. By using capacitors with appropriate capacitance values and switching frequencies, the converter achieves efficient power conversion without the harmful electromagnetic effects associated with inductors, thus resolving the contradiction between efficiency and noise.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If battery capacity is increased to extend mobility time, then duration of action is improved, but device dimensions and weight increase

Engineering Contradiction:

Improvemobility timeVSAvoiddevice dimensions

Core Design Contradiction:

Duration of action of moving objectVSVolume of moving object

Solution Approach 1:

The patent converts the harmful effect of high current demand from traditional regulators into a benefit by using switched capacitor technology. The high current switching operation of capacitors enables efficient power conversion with reduced ripple, allowing the system to maintain high performance with smaller battery capacities, thus extending mobility time without increasing device dimensions.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If switching frequency is increased to improve power conversion efficiency, then power conversion efficiency is improved, but switching losses and thermal issues increase

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidswitching losses and thermal dissipation

Core Design Contradiction:

Loss of energyVSPower

Solution Approach 1:

The patent replaces inductor-based switching with capacitor-based switching, which has different loss characteristics. Capacitor switching eliminates core losses and copper losses associated with inductors, reducing thermal dissipation even at higher switching frequencies, thus maintaining power conversion efficiency without excessive thermal issues.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides high power conversion efficiency over a wide range of output currents, reduces noise and thermal issues, and allows for variable switching frequency, extending efficiency to light loads while maintaining high conversion efficiency.

Implementation Method 1

The power converter may comprise a plurality of flying capacitors (also referred to as switching capacitors). The plurality of flying capacitors may comprise two or more capacitors.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the power converter may comprise a plurality of switches which is configured to arrange the plurality of flying capacitors in accordance to a sequence of (different) operation phases

Methodology Applied

Scientific EffectElectrical switching:

Data Source

PatentUS9997999B2Capacitive DC power transformer

Publication Date: 2018.06.12 DIALOG SEMICON GMBH

AI summary

The present document relates to power transformers for electronic computing devices. In particular, a power converter configured to convert electrical power at a DC input voltage Vin into electrical power at a DC output voltage is described. The power converter comprises a plurality of flying capacitors, and a plurality of switches which are configured to arrange the plurality of flying capacitors in accordance to a sequence of operation phases. The power converter comprises a control unit configured to control the plurality of switches to repeat the sequence of operation phases at a duty cycle frequency. The plurality of flying capacitors is arranged in series during the operation phases of the sequence of operation phases. The sequence of operation phases comprises at least two operation phases during which the plurality of flying capacitors is arranged in a different order.