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Silvan Ho Wireless Power Solutions | MediaTek
[email protected] Nov 12, 2015
Multi Mode Receiver Design
To Accelerate Wireless Power Market Adoption
User Case & Technology Limitation ▪ MI - Magnet Induction
• Tightly Coupling • Low Q system (~25@RX) • Coupling Coefficient K : 50~70% • Majority of B field lines must be
captured
MR – Magnet Resonance – Loose Coupling – High Q System (~125 @RX) – Coupling Coefficient K : 6~12 % – Only significant numbers of B field
lines need to be captured – Z height possibility
Standard Trend
3
LP 1.1.2
MR
LP
BSS 1.2
WPC1.2
BSS 1.3
Dual Mode Same Technology MP
Jun 2015 Rls
AirFuel, from Nov 2015
MI Today
MR Trend
MediaTek MT3188
WPC PMA A4WP
Each Standard Has Benefits
Feature/Benefit Qi PMA A4WP Notes
Market maturity, lowest cost today
++ + Qi & PMA have been in the market for years, Qi has the highest volume
Coil Area (e.g. 5W Phones) X X 2-3X
Power control IB IB BLE IB = In Band, potentially lower cost
Efficiency ++ ++ + Due to tight coupling and frequency choice
EMI sensitivity ++ ++ + Tight coupling minimizes stray EMI
Freedom of placement + + ++ Loose coupling
Interoperability of different size coils / power levels
+ + ++ Loose coupling
Multiple device support No No Yes With a single Tx coil
Distance Charging + + ++ Low = ~ 5mm, High = ~45mm
Charging continuity in presence metals
+ + ++ Sensitivity to metals causes FOD schemes to interrupt or prevent charging
Note : Based on standards Qi 1.1.2, PMA 1.0, A4WP 1.2
Tightly Coupled, low frequency
Loosely coupled, high frequency
The Need of Multi-Mode
Standard – Competition on going, WPC vs AirFuel (A4WP+PMA) – Standard Unification takes time – MM solution get the rid of market confusion
User Experience – User education on standard difference is difficult – An open platform for user to experience the different
technology/standard
Technology – Maturity/Efficiency, MI >> MR – Spatial Freedom, MR >> MI
MM solution will speed up the market adoption !!
Multi-Mode, TX vs RX?
Power Path
WPC/A11/FB WPC/A6/HBx3 PMA/HB A4WP/Class E
▪ If all the RX are MM, then the TX will not need to be MM, and vice versa.
MM TX
MM RX
Is there a TX type approved across the
standard?
Frequency of Operation Does Create a Fence
Copyright © MediaTek Inc. All rights reserved. 7
Loosely Coupled
HF TX
RX
Tightly Coupled
LF TX
RX
Fence of Operating Frequency
277-357kHz
6.78 MHz
110-205kHz
The Answer…
Inductive Mode Resonance Mode
▪ QVL : Amotech, Gotrend
MT3188 Module w/ EMI Optimization
55mm
73 mm
0.8mm max
▪ Major challenge on A4WP mode, 6.78MHz frequency
Kupiin Product – Commercial Ready
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