Wireless Power Transfer

Wireless Power Transfer

Overcoming the Technological Hurdles

Francesco Carobolante

DISCLAIMER: The information provided in this presentation is for informational purposes only and is not intended to be, and should not be taken as or construed to be, legal and/or regulatory advice or recommendations. You should consult a lawyer or other advisor if you want professional assurance that the information in this presentation, and your interpretation of it, is accurate and/or appropriate to your particular situation. Any reliance upon any opinion, advice, statement, diagrams or information contained in this presentation shall be at your sole risk. Qualcomm Incorporated makes no representation, neither expressly nor impliedly, as to the accuracy, completeness, timeliness or reliability of the materials or any information contained in this presentation.

Wireless power has a long history

1901: Resonant Magnetic Induction

1902: Wireless Energy Transmission

Wireless Charging Landscape

Conven

ienc

e

Long Range: Far-field RF

Short to Medium Range:

Near Field Resonance

Short Range: Inductive Coupling

Zero Range: Conductive Mat

Coupling of RF energy to a device with a small receiver antenna with device in the RF far field

Device is brought within near field of a low frequency TX antenna. RF energy couples to device with small receive antenna

where it is rectified for device charging

Coupling of RF energy when a device with a small receive antenna is placed on a “charging surface” containing the transmit elements

Current flows through the pad to a conductive adapter in the device

General Wireless Power Transfer Model

(multiple receivers)

Overcoming the Technological Hurdles

Regulatory

Standardization

Commercial

Readiness

Use Case

Overcoming the Technological Hurdles

Regulatory

Standardization

Commercial

Readiness

Wireless Power Needs to Support

Simultaneous Charging of Multiple Devices and Types

Source: Qualcomm omnibus survey: Base: US Consumers Who Own Traditional Mobile Phone or Smartphone and Are At Least Somewhat Interested in the Wireless Charging Concept (n=657 and n=483)

1% 2% 3% 4% 11% 11% 12% 12% 13% 18% 25% 34% 34% 45% 74% 0% 10% 20% 30% 40% 50% 60% 70% 80% UMPC Netbook Portable Satellite… Mobile Internet… Portable DVD Playe Portable Media… Portable… Camcorder Handheld Game Smartphone Bluetooth Headset MP3 Music Player Laptop Digital Camera Mobile Phone Multiple Devices Single Device

Preferred Number of Devices to Be Simultaneously Charged

Devices Likely to Buy and Use with Wireless Charging

Flexible Coupling

A Truly Universal Solution

NOT specific to device type

No need to specify location

No alignment required

Delivers Spatial Freedom

−

X/Y Placement

− Benefit: Plenty of Room for up to 3

smartphones or a single tablet

−

Simultaneously Delivers Z Freedom

− Benefit: Users can charge seamlessly in all

environments

Multi-Device Charging

Multi-Device Type Charging

A4WP Technologies Clear the 1st Hurdle

Meets Consumers Use Case Requirements

Overcoming the Technological Hurdles

Standardization

Commercial

Readiness

FCC1 _{limit of 1.6 W/kg on 1g SAR}2 _{to prevent tissue heating for f > 100 kHz}

ICNIRP3 _{1998 and 2010 standards for induced current density (J) and induced electric field (E) between 1 Hz} and 10 MHz to prevent nerve stimulation in both central and peripheral nervous systems (CNS and PNS)

− 2010 standard specifies the E limits for both CNS and PNS

− 1998 standard was based on effects seen in CNS from biological studies but specifies the induced J limits for all tissues in head and trunk regions

As of today, ICNIRP 2010 standard has not been adopted by regulatory bodies. Hence, human exposure should be qualified for all exposure quantities in 100 kHz to 10 MHz frequency range:

Human Exposure Limits

1 _{Federal Communications Committee} 2 _{Specific Absorption Rate}

A simulation methodology is necessary to assess RF

exposure with respect to ICNIRP basic restrictions

Numerous wireless power uses cases have been

evaluated by Qualcomm to determine whether the

regulatory requirements can be achieved. A few

examples are as follows:

− Next to a tray placed on a table

− Next to a nightstand

− Working at a desk with embedded TX

− Hands on a driving wheel

− A hand on driving wheel and the other near a gear shift

Each use case evaluated show results below the

regulatory requirements

Exposure Estimation for Embedded Desktop Module

6.8 AT_rms corresponds to 25 W of power transferred to the load in the embedded system. For the same load, 37 W of power can be delivered when the worst case reaches the exposure limit.

Both the Low frequency solution (468KHz) and The higher frequency solution

(6.78MHz) for the desired use case meet the FCC requirements

Regulatory Emissions Requirements

Radiated emissions assessment per

FCC Pt.15/18 US limits

Emission comparison with FCC limits

FCC Pt.15 limit FCC Pt.18 limit RE of charging at 468kHz RE of charging at 6.78MHz

Limits @300m Limit @30m

Unrestricted limit at ISM 6.78MHz

Low frequency solution (468KHz) for the

desired use case does not meet the CISPR 11

requirements

The higher frequency solution (6.78MHz) for

the desired use case meets the CISPR11

requirement

Radiated emissions assessment per

CISPR

_{11 Int’l limits for ISM Equipment}

1 _{Comité International Spécial des Perturbations Radioélectriques}

468kHz, H=60.50 6.78MHz, H=54.07 0 10 20 30 40 50 60 70 0.10 1.00 10.00 H-field (d BuA /m) Frequency (MHz)

Emission comparison with CISPR 11 limits

CISPR11 G2B limit@3m CISPR 11 cooker limit@3m RE of charging at 468kHz RE of charging at 6.78MHz

Unrestricted limit at ISM 6.78MHz

Wireless Power Compliance

−

Regulatory categorization depends on

frequency of operation and signaling

approach

− ISM or other category of equipment

−

Frequency selection is critical to ensure

compliance with radiated emissions limits

−

Wireless power compliance with RF

exposure should be assessed using “Basic

Restrictions”

− Dependency on frequency, power, loop

geometry and use case definition

−

Regulators currently assessing wireless

power and applicability of existing rules

A4WP Technologies Clear the 2nd Hurdle:

Regulatory Requirements

Overcoming the Technological Hurdles

Commercial

Readiness

Use Case

Regulatory

Standardization

Purpose

− Enable a global wireless power transfer ecosystem based on a non-radiative, near-field magnetic resonance

approach

− Deliver Wireless Power Transfer (WPT) spatial freedom

Vision

− Be the primary venue supporting the evolution of wireless power transfer technologies, products and

services based on a non-radiative, near-field magnetic resonance approach

Mission

− Global standardization

− Certification and testing

− Regulatory compliance and policy

Alliance for Wireless Power

Open System

Many Opportunities for Innovation and Differentiation

ZIN_RX’ ZIN_RX Z21 ZIN_TX ITX +

Alliance for Wireless Power Ecosystem

Membership — 38

Automotive Carrier Consumer Devices Components Furniture Technology Design, Test & Certification

The technical working committee has

been established

− Responsible to develop, maintain and execute

the A4WP Technical Program focused on the development and maintenance of a Wireless Power Transfer Technical Specification

− The baseline system specification has been APPROVED and released to the membership

The following committees have

also been established:

− Certification Working Committee

− Regulatory Working Committee

− Marketing Working Committee

A4WP Technologies Clear the 3rd Hurdle:

Standardization Requirements

Overcoming the Technological Hurdles

Use Case

Regulatory

Standardization

Commercial

Readiness

Meeting the needs of the Smartphone is a key driver for the wireless power market to

achieve its potential

− 74% of questioned Smartphone users are likely to buy and use wireless charging1

Some of the Keys to Smartphone Adoption:

− Meeting the use case described earlier

− Meeting charge time, touch and battery temperature requirements

− Meeting radio coexistence requirements

− Ensuring metal objects in or near the field do not have a significant temperature rise

Technology Meeting Commercial Readiness

Meeting Charge Time, Battery, and Touch Temperature

Requirements

A4WP-compatible Technologies Meet Charge Time, Battery, and Touch Temperature Requirements Based on Commercial Benchmarks

Performance relative to a “wired” charger WiPower Receiver Multicharger Commercially Available WPT Solution Charge power (% of wired charger Power) 73% 57% % of Max outside

case temp. spec. 96% 81%

% of Max

touch-screen temp. Spec 76% Not measured

% of Max battery

temp. Spec. 76% 82%

Time to charge termination (% of wired charger time)

Meeting Radio Coexistence Requirement:

WWAN (GSM, CDMA, LTE, etc.), GPS, Wi-Fi, Bluetooth, and NFC

Qualcomm has

over 25 years

experience

ensuring radio

coexistence

Qualcomm Regulatory

team performs

link budget analysis to

characterize

degradation due to

noise and isolation/

rejection needed

per design

Coexistence is

addressed at the

implementation level

with OEMs

WWAN Coexistence Reference Specs

Applications

TIS1 _{Specs for}

Phone by Carriers

TIS Specs by UE Vendors or Std

OEM Specs for Degradation by

Accessory

Derived Min TIS Due to Interference

by WiPower

Source Docs

CDMA 850 _{Spec. Provided, [1]} Spec.

Provided,[6] Spec. Provided, [1] Carrier 1 specs

CDMA 1900 _{Spec. Provided, [2]} Spec.

Provided,[6] Spec. Provided, [2] Carrier 2 specs

GSM 850 _{Spec. Provided, [3] Spec. Provided, [4]} Spec.

Provided,[6] Spec. Provided,

[3] Carrier 3 specs

GSM 900 _{Spec. Provided, [3] Spec. Provided, [4]} Spec.

Provided,[6] Spec. Provided,

[4] 3GPP TSG RAN WG4-#52

GSM 1800/1900 Spec. Provided, [3] Spec. Provided, [4] Spec.

Provided,[6] Spec. Provided,

UMTS 2100 _{Spec. Provided, [3] Spec. Provided, [5]} Spec.

Provided,[6] Spec. Provided,

[5] GSMA SE.43 v3.0

GPS _{Spec. Provided,} [6] XX OEM

accessory specs

WLAN Spec. Provided, based

on data rate [7]

[7] 802.11x standard

BT _{Spec. Provided, [8] [8] BT RF Specs}

Example of Test Results and Design Guidance

The radiated performance is device specific. Below highlights the guidance for performance improvement

Platform Technology

and Band

Worst

Position Highest EISmin (dBm)

% Delta Margin (dB) to Derived Spec.

(assuming 3dBi antenna gain)

Device 1 CDMA BC0 4 Spec Provided

1.7%

CDMA BC 1 7 Spec Provided 0.3%

Device 2 CDMA BC 0 4

† _{Spec Provided 1.2%}

CDMA BC1 1† Spec Provided 0.2%

†: only one position was checked for Device 2

Noise sources Mitigation solution

Harmonics from Tx (amplifier)

• Low-pass filter at PA output • Isolation between Tx coil and

WWAN antenna Harmonics

from Rx (rectifier)

• EMI filter between Rx coil and rectifier

• Isolation between Rx coil and WWAN antenna

Ensuring Metal Objects in or Near the Field Do Not Have a

Significant Temperature Rise

Wireless Charging Solutions

Operating in the 100s of KHz

Range Generate ~10x the

Amount of Induced Power in

Foreign Objects as That of

6.78 MHz Systems

Evaluation platforms have

demonstrated that the

technology can

−

Meet the charge time, touch and battery

temperature requirements

−

Meet radio coexistence requirements

−

Deliver a SPATIAL FREEDOM use case

while ensuring objects in or near the

field

do not have a significant

temperature rise

A4WP Technologies Clear the 4th Hurdle:

Commercial Readiness Requirements

Commercial

Readiness

Overcoming the Technological Hurdles to Drive

Wireless Power into the Mainstream

Wireless Power Selection Checklist

A4WP

Meets

Use Case

Requirements

Delivers Spatial Freedom (Simultaneously meeting X/Y and Z)



Simultaneous charging of multiple devices



Simultaneous charging of multiple device types



Meets Regulatory Requirements ICNIRP







Charge Time, Touch and Battery Temperature Requirements



Mobile Phone Coexistence



Regulatory

Standardization

Commercial

Readiness

Overcoming the Hurdles to Drive

Wireless Power into the Mainstream

Use Case

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