OVERVIEW OF WIRELESS CHARGING

Transcription

1 OVERVIEW OF WIRELESS CHARGING Wearables TechCon March 11, 2015 Naomi Lee Wireless Charging Program Manager 2015 Underwriters Laboratories Inc.

2 Wireless Power Transfer The mobile industry is transitioning to wireless charging solutions giving users more convenience to no longer need to carry chargers or wired power adapters while traveling. There are three wireless alliances striving to be The Wireless Charging Standard in the industry. WPC was established in December 2008 and Qi low power specification was published in August 2009 based on Inductive power transfer. PMA was established in March 2012 and PMA s Receiver specification was published in 2014 based on Inductive power transfer. A4WP was established in March 2012 and Rezence Baseline Specification was published in 2013 based on Resonance power transfer. 2

3 Wireless Power Transfer Summary of differences in the three alliances. Frequency of Operation khz khz 6.78 MHz Alignment Close *Introducing Loose Alignment, Q1/Q Close Loose Communication Channel In-Band with Frequency of Operation In-Band with Frequency of Operation Out-of-Band using Bluetooth NOTE: PMA and A4WP announced they will merge to become one alliance by June

4 Tightly coupled versus Loosely coupled Tighter the coupling, higher the power transfer efficiency, lower power loss and less heat produced. Tight coupling is more advantageous for devices with limited thermal budgets as smartphones or tablets. Tightly coupled transmitter and receivers have the same size coils and smaller Z distance than the coil diameter. Both transmitter and receiver coils have ferrite shielding therefore less EMI/EMF emissions 4

5 Tightly coupled versus Loosely coupled Loosely coupled systems trade-off lower efficiency power transfer with greater distance separation. Loosely coupled systems have less power transfer therefore a resonance circuit is needed to improve the power transfer across distances. In loosely coupled systems, a fraction of the power is transferred to the receiver therefore there are higher EMI/EMF emissions than tightly coupled systems. 5

6 Tightly coupled versus Loosely coupled Loosely coupled coils operate at a larger distance or operate with significantly different coil sizes. 6

7 Wireless Power Consortium (Qi) Qi was the first of the three alliances for Wireless Power Transfer. Qi s Wireless Power Transfer is based on Magnetic Inductance with close alignment. UL Japan is an accredited test lab for conformance tests. All Interoperability tests conducted by a third party lab. 7

8 Wireless Power Consortium (Qi) Mobile Conformance Tests (Receiver): Test No. Mobile Testing Test Description 1 Conformance to Communications Interface Requirements - Load Modulation 2 Conformance to System Control Requirements - Digital Ping: Packet Timing 3 Conformance to System Control Requirements - Digital Ping: Packet Content 4 Conformance to System Control Requirements - Digital Ping: Signal Strength 5 Conformance to System Control Requirements - Digital Ping: Packet Timing 6 Conformance to System Control Requirements - Identification & Configuration: Packet Sequence 7 Conformance to System Control Requirements - Identification & Configuration: Packet Timing 8 Conformance to System Control Requirements - Identification & Configuration: Packet Content 9 Conformance to System Control Requirements - Power Transfer: Packet Timing 10 Conformance to System Control Requirements - Power Transfer: Packet Content 11 Conformance to System Control Requirements - Power Receiver: Reset 12 Conformance to System Performance Requirements - Guaranteed Power 8

9 Wireless Power Consortium (Qi) Base Station Conformance Tests (Transmitter): Test No. Base Station Testing Test Description 1 Conformance to Communication Interface Requirements - Load Modulation 2 Conformance to System Control Requirements - Selection phase 3 Conformance to System Control Requirements - Digital Ping: Power Signal Characteristics 4 Conformance to System Control Requirements - Digital Ping: No Response 5 Conformance to System Control Requirements - Digital Ping: Signal Strength 6 Conformance to System Control Requirements - Digital Ping: Termination 7 Conformance to System Control Requirements - Identification & Configuration: Packet Sequence 8 Conformance to System Control Requirements - Identification & Configuration: Packet Timing 9 Conformance to System Control Requirements - Identification & Configuration: Communication Error 10 Conformance to System Control Requirements - Identification & Configuration: Packet Content 11 Conformance to System Control Requirements - Power Transfer: Packet Sequence 12 Conformance to System Control Requirements - Power Transfer: Packet Timing 13 Conformance to System Control Requirements - Power Transfer: Packet Content 14 Conformance to System Control Requirements - Power Transfer: Packet Control 15 Conformance to System Control Requirements - Power Transfer: Termination 16 Conformance to System Performance Requirements - Guaranteed Power 17 Conformance to System Performance Requirements - Thermal Performance 18 Conformance to System Performance Requirements - Foreign Object Detection 19 Conformance to System Performance Requirements - User Interface: Object Placed 20 Conformance to System Performance Requirements - User Interface: Transfer in Progress 21 Conformance to System Performance Requirements - User Interface: Transfer Complete 22 Conformance to System Performance Requirements - User Interface: Fault 23 Conformance to System Performance Requirements - User Interface: Multiple Devices 24 Conformance to System Performance Requirements - User Interface: Limited Power 9

10 Power Matters Alliance (PMA) The PMA is another alliance striving to standardize the wireless charging technology in the industry. PMA is also based on magnetic inductance with close alignment. Certification is based on conformance and interoperability tests. UL Fremont is the Lead Lab for PMA. UL Taiwan is also an accredited test lab. 10

11 Power Matters Alliance (PMA) Receiver Testing and Certification of PMA Receiver devices are tested to verify the device meets the requirements of the PMA specifications on a a customized Test Equipment which was validated by UL. Measurements are conducted such as coupling coefficient, efficiency, output voltage and notification that charge is complete. Devices are also tested for interoperability functionality with available transmitter devices to ensure the wireless charging does not interferes with the device performance. 11

12 Power Matters Alliance (PMA) Receiver Conformance Tests: Test No. RX Testing Test Description 1 Detection - DC Magnetic Field Results 2 Detection - Alignment 3 Detection - Coupling Coefficient 4 Digital Ping - Engagement with Charging Surface 5 Digital Ping - Digital Ping Operation 6 Digital Ping - Output Voltage 7 Digital Ping - UCD Charging Notification 8 Identification - Stabilization Period 9 Identification - Message Correctness 10 Communication - Modulation 11 Charging Performance - Long Cycle Test 12 Charging Performance - Switch Load 13 Charging Performance - Efficiency 14 Power Termination - Regular End of Charge 15 Safety and Protection - Over Current Protection 16 Safety and Protection - Over Temperature Protection 12

13 Power Matters Alliance (PMA) Receiver Interoperability Tests: Test No. Interoperability Test Description 1 Scenario 1A - Engagement with Charging Surface - Basic Charging 2 Scenario 1A - Engagement with Charging Surface - Wired charging connected before placement 3 Scenario 1A - Engagement with Charging Surface - Wired charging connected after placement 4 Scenario 1A - Engagement with Charging Surface - Charging depleted battery 5 Scenario 1A - Engagement with Charging Surface - Low battery in misalignment condition 6 Scenario 1A Engagement with Charging Surface - IUT temperature 7 Scenario 1A Range of Motion Within Tx Operational Range 8 Scenario 1A Range of Motion In and Out of Tx Operational Range 9 Scenario 1B Touch Screen Performance More test cases will be added once validated by PMA. 13

14 Power Matters Alliance (PMA) Transmitter Testing and Certification of PMA Transmitter compliance specifications are still in development. Compliance test specifications to be defined by end of Q Conditional certification can be provided with conducting transmitter interoperability tests with available receiver devices. Once the compliance specifications are finalized the transmitter must be resubmitted for conformance testing for final certification. 14

15 Power Matters Alliance (PMA) 15

16 Alliance For Wireless Power (A4WP) The A4WP or Rezence is another of the three alliances. Rezence provides wireless charging with spatial freedom and based on Magnetic Resonance with loose alignment. This allows for flexible device placement and charging through surfaces. UL is working closely with A4WP to become a lab by Q UL Fremont will host the next PlugFest at the end of March. 16

17 Alliance For Wireless Power (A4WP) Rezence Certification Program currently test both receiver and transmitters manually. Rezence is working on an automated testbed solution. Certification has both Conformance and Interoperability functionality tests. 17

18 Alliance For Wireless Power (A4WP) 18

19 Questions 19

20 Backup 20

21 Wireless Power Consortium (Qi) Base Stations = Transmitter type difference summary Base Station Type A Description Based on a single Primary Coil Type B Based on an array of Primary Coils Mobile Devices = Receiver Low power specifications transfers around 5W of power. 21

22 Power Matters Alliance (PMA) Transmitter type difference summary Power Class Tx Type PMA-1 PMA-3 Description Basic single coil design. Used as a reference for testing. Transmitter type installed in Averna testers. Enhanced performance single coil design. Design to be rolled out to all Starbucks globally. 0 (5W) 1 (10W) 2 (15W) 3 (20W) 4 (30W) 5 (40W) 6 (50W) 7 (70W) X X PMA-4 Enhanced performance single coil design to support up to Class 2. X X X PMA-5 Enhanced performace multi-coil design to support up to Class 2. X X X 22

23 Alliance for Wireless Power (A4WP) PTU Power Transfer Unit for BSS* 1.3 Class Type Power TX_IN_MAX (Maximum Input power to the resonator) Min Category Support Min Value for Max # of device support Class 1 2W 1 x Category 1 1 x Category 1 Class 2 10W 1 x Category 3 2 x Category 2 Class 3 16W 1 x Category 4 2 x Category 3 Class 4 33W 1 x Category 5 3 x Category 3 Class 5 50W 1 x Category 6 4 x Category 3 Class 6 70W 1 x Category 7 5 x Category 3 * BSS = Baseline System Specification 23

24 Alliance for Wireless Power (A4WP) PRU Power Receiver Unit for BSS 1.3 Category Type Power RX_OUT_MAX (Maximum output power of the PRU resonator) Examples Category 1 TBD BT headset Category 2 3.5W Feature phone Category 3 6.5W Smart phone Category 4 13W Tablet, Phablet Category 5 25W Small Form Factor Laptop Category W Regular Laptop Category 7 50W 24