Adiabatic Switched-Capacitor Network for Battery Power Management

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Solution Overview

Problem

Battery managers in portable devices face challenges in efficiently switching between powering from a battery and an AC source, particularly in managing charge transfer and voltage regulation to optimize energy usage and reduce power loss.

Innovation Solution

The implementation of an adiabatic switched-capacitor network within the battery manager, which includes a capacitor with charge stored and circuitry to constrain the rate of charge change by passing it through inductance, along with a controller to transition between states at a specific frequency, enabling efficient charge transfer and voltage regulation between the battery and AC source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional switched-capacitor circuits are used for power conversion, then the device can switch between battery and AC power sources, but energy loss increases and efficiency decreases

Engineering Contradiction:
Improvepower lossVSAvoidenergy transfer efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent changes the operating parameters of the switched-capacitor circuit by implementing adiabatic switching, where the switching frequency and timing are optimized to minimize energy loss. The circuit operates in an adiabatic regime where charge transfer occurs slowly enough to avoid resistive losses but quickly enough to maintain efficiency, fundamentally changing the parameter space of operation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary inductance element in the switched-capacitor circuit that mediates the charge transfer between capacitors. This inductance smooths the current flow and enables adiabatic charging/discharging of capacitors, reducing energy loss during switching transitions while maintaining effective power conversion

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If fast switching is implemented to improve response time, then the device can quickly switch between power sources, but energy loss increases due to resistive heating

Engineering Contradiction:
Improveswitching speedVSAvoidresistive power loss
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The patent optimizes the switching parameters by operating in an adiabatic regime where the switching frequency and duty cycle are carefully controlled. The switching speed is tuned to balance between response time and energy loss, achieving fast switching without excessive resistive heating by operating at optimal frequency points

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The inductance element serves as an intermediary that decouples the direct relationship between switching speed and resistive loss. By introducing this intermediate energy storage element, the circuit can switch quickly while the inductance smooths current transitions, preventing sharp current spikes that would cause resistive heating

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If voltage regulation is tightened to improve power quality, then the output voltage remains stable, but energy efficiency decreases due to increased regulation losses

Engineering Contradiction:
Improvevoltage stabilityVSAvoidregulation loss
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent uses the inductance element as an intermediary that provides natural voltage smoothing and regulation. This inductive impedance acts as a buffer that stabilizes output voltage without requiring aggressive active regulation, thereby maintaining voltage stability while minimizing regulation losses through passive energy storage and release

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

This solution enhances the efficiency of energy transfer, reduces power loss, and allows for seamless switching between battery and AC power sources, improving the overall performance of battery managers in portable devices.

Implementation Method 1

an adiabatic switched-capacitor network. Such a network is characterized by having a capacitor with charge stored thereon circuitry for constraining a rate of change of the charge at least in part as a result of causing charge to pass through an inductance

Methodology Applied
Scientific EffectAdiabatic process:

Implementation Method 2

causing charge to pass through an inductance

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the controller causes the switched-capacitor network to transition between the first state and the second state at a specific frequency, thereby transferring charge between capacitors and terminals of the switched-capacitor network

Methodology Applied
Scientific EffectPeriodic switching:

Data Source

PatentEP4135181A1Battery management system with adiabatic switched-capacitor circuit
Publication Date: 2023.02.15 MURATA MFG CO LTD
  • EP4135181A1 patent drawingFigure 1~2
  • EP4135181A1 patent drawingFigure 3~4
  • EP4135181A1 patent drawingFigure 5~7

AI summary

An apparatus for switching between powering a load from a battery and powering the load from another power source includes a battery manager and a switched-capacitor network.