Wireless Charging – #3

Wireless charging is growing in popularity! Learn about the difference between inductive and resonant techniques, as well as who’s implementing the technology (it might surprise you!). Daniel Bogdanoff, Brig Asay, and Johnnie Hancock discuss.

 

Video (YouTube):

Discussion Overview:

Intro 00:00
Efficiency measurements for wireless charging system 01:02
Basics of wireless charging 01:53
Phones without built-in wireless charging functionality
Phone case to enable wireless charging 02:05
Wireless charger and phone as primary and secondary transformer 02:16

 

Magnetic Inductive vs Magnetic Resonant techniques for Wireless Charging

Magnetic resonance versus inductance for wireless charging 02:39
Magnetic inductance 02:54
Qi technology 03:05

Rezence/Airfuel/A4WP (alliance for wireless power)
Magnetic inductance runs at a lower frequency 03:21
Device communication – “ping” 03:30
Load change, load modulation, handshaking 03:39
Spool of wire as load 04:05
Two main states – polling/power save 04:23
Magnetic resonance 04:39
Proximity of device to charging pad for magnetic inductance charging  05:00

Charge multiple devices wirelessly with magnetic resonance using one large charging coil 05:31

Can you mount a charging pad under table/surface? 05:46
Surface material types that do and do not allow charging 06:07

 

Where is wireless charging available?

Integration of wireless charging into non-electronic devices 06:28

New infrastructure – Furniture makers, coffee shops 06:52
Wireless charging pads built into furniture 07:01
Magnetic inductance, built into surface of furniture 07:06
Coffee shops in the future may have wireless charging in the tables and counters
Wireless charging might not be free 07:35
Near field communication (NFC) 07:52

 

Is wireless charging secure?
There’s a possibility of data transfer (non power-related information) 08:04
Magnetic resonance has parallel communication path 08:39
Bluetooth protocol will be used to transfer more information 08:51

 

Wireless charging in cars and furniture

Automotive integration of wireless charging 09:36
Why is this better than plugging the phone in directly? 10:24
Wireless chargers embedded in furniture
Sold at furniture stores 11:18
Standards for distance from charging pad 12:26
Charging from far distances using repeater systems and magnetic resonance 14:28

 

How to tune a wireless charging device

Tuning a wireless charging device 15:01
Network analyzer for tuning, impedance matching 15:12

Oscilloscopes can also be used for tuning
Why don’t we have this technology everywhere right now? 15:44
Slowed down by lack of a single standard 16:06
Magnetic resonance versus inductance for future technology 16:34
Companies and standards – one technology will win
Influencers of the consortium – manufacturers, tech companies, etc. 18:54
Trade offs 19:31
Efficiency, cost, multiple devices
What is the efficiency of wireless charging? 20:12
Wireless charging efficiency for bigger device – electric car 20:45
Safety, government regulations 21:18
Texas A&M professor – what does electric radiation do to people? 22:07
NFC – Apple Pay, Samsung Pay, etc. 22:38
Wirelessly charge wearables, medical implants 23:16
Wireless charging pacemakers
How much power can we really transfer wirelessly? 24:53
Charging all devices inside a single room?
Predictions for the future of wireless power 26:24

 

Read Johnnie’s wireless charging application notes:

 

Part 1: Measurements during the power transfer state

Part 2: Measurements during the power save state

Part 3: Power and efficiency measurements

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