Switched Capacitor Power Management for High-Current Charging

Solution Overview

Problem

Battery-powered devices face challenges in high current charging, which increases charging time but can violate current specifications, generate excessive heat, and reduce reliability, while existing inductor-based converters have efficiency limitations and thermal issues.

Innovation Solution

A power management device utilizing a switched capacitor converter and an inductor in parallel with a switch, configured in various modes to regulate power transfer efficiently, including step-down and buck-boost configurations, with inner and outer loop power controls to manage voltage and current, reducing heat generation and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high current charging is used to reduce charging time, then charging speed is improved, but current specifications are violated and reliability deteriorates

Engineering Contradiction:

Improvecharging speedVSAvoidcharging reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The charging system is segmented into multiple power paths: a first power path with a switched capacitor converter for high-current charging and a second power path with an inductor-based converter for standard charging. This segmentation allows the system to distribute charging current across different paths, enabling high charging speed while maintaining reliability by not overloading a single path.

Inventive Principle:

Principle #1Segmentation

2Productivity

If high current charging is used to reduce charging time, then charging speed is improved, but heat generation increases

Engineering Contradiction:

Improvecharging speedVSAvoidheat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The charging system is segmented into multiple power paths: a first power path with a switched capacitor converter for high-current charging and a second power path with an inductor-based converter for standard charging. This segmentation allows the system to distribute charging current across different paths, enabling high charging speed while maintaining reliability by not overloading a single path.

Inventive Principle:

Principle #1Segmentation

3Power

If inductor-based converters are used for power conversion, then power transfer is achieved, but efficiency is limited and thermal issues occur

Engineering Contradiction:

Improvepower transfer capabilityVSAvoidconversion efficiency

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

A switched capacitor converter is introduced as an intermediary component in the first power path between the first power source and the second power source. This intermediary enables efficient high-current power transfer with reduced energy loss compared to traditional inductor-based converters, achieving mid-90% efficiency by utilizing capacitor-based switching rather than inductor-based switching.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If current is reduced through power cables to meet specifications, then reliability is improved, but charging time increases

Engineering Contradiction:

Improvecharging reliabilityVSAvoidcharging time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The charging system is segmented into multiple power paths: a first power path with a switched capacitor converter for high-current charging and a second power path with an inductor-based converter for standard charging. This segmentation allows the system to distribute charging current across different paths, enabling high charging speed while maintaining reliability by not overloading a single path.

Inventive Principle:

Principle #1Segmentation

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 reduces current through power cables, increases charging circuit efficiency to mid-90%, and minimizes heat generation, addressing the limitations of inductor-based converters by configuring the power management device in different operational modes to achieve efficient and reliable high-current charging.

Implementation Method 1

a switched capacitor converter; wherein the switched capacitor converter is coupled between the first port and one end of the inductor coupled in parallel with the switch

Methodology Applied

Scientific EffectCapacitive switching: Capacitance

Implementation Method 2

an inductor coupled in parallel with a switch; wherein another end of the inductor coupled in parallel with the switch, is coupled between the switched capacitor converter and the second port

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3312968B1System and method for power management

Publication Date: 2021.04.28 NXP BV

Figure 1
Figure 2
Figure 3

AI summary

One example discloses a power management device, including: a first port configured to be coupled to a first power source; a second port configured to be coupled to a second power source; a switched capacitor converter; and an inductor coupled in parallel with a switch; wherein the switched capacitor converter is coupled between the first port and one end of the inductor coupled in parallel with the switch; and wherein another end of the inductor coupled in parallel with the switch, is coupled between the switched capacitor converter and the second port.