Maximizing Wireless Power Performance In Constrained Environments. Michael Gotlieb Vice President of Business Development

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1 Maximizing Wireless Power Performance In Constrained Environments Michael Gotlieb Vice President of Business Development

2 Agenda Wireless Power Markets Focus of This Presentation: Constrained Environments within Qi Certified, Qi Friendly What Problem Are We Solving? Performance Defined Practical Ways to Maximize Performance Conclusion CONFIDENTIAL 2

3 Wireless Power Markets In Production or In Design Today; Broadening Landscape Discussion Focus Consumer Mobile Phones Wearable, Personal Devices Peripherals; Laptops Medical Hearing Aid Sanitized Rechargeable Portable Equipment Automotive Accessory / Sleeves In Car Embedded In Car Consumer Device Mil-Aero Airplane Trays/Seats Soldier Equipment Robotics Infrastructure Office Furniture Coffee Shops Hotels Industrial Wireless Sensor Networks Contact Replacements Power Tools

4 Wireless Power System Environments Highlights of In-Production or In-Design Today Consumer Mobile Phones 0.25mm 0.40mm thin (Coil + Ferrite ) Z gap 3mm Watts Wearable, Personal Devices 0.25mm 0.6 mm thin Z-gap 3 mm+ 1Watt + Flexible/Bendable Medical Hearing Aide 8.5mm-12mm DIA 0.5mm thin Z gap 3 mm <1 Watt Why Wireless Power Designers Portable Equipment Go Thin and Small? +Add Other Product Features +Increase Battery Size +Industrial Design Forces Size +Cost +Retrofitting Existing Products Automotive Accessory / Sleeves 0.3mm mm Z gap 3 mm 5 15 Watts In-Car Embedded Armrest/Console Pad size 1mm thickness Z gap >10mm (Qi Friendly) 5W 15Watts

5 Any fool can make wireless power work, but making it work at a reasonable cost with reasonable performance takes considerable engineering skills, Robertson told Electronics Weekly (former) Senior Vice-President at IDT Graham Robertson CONFIDENTIAL 5

6 Wireless Power Systems Interrelated Stages Impact 1)User Experience 2)Efficiency / Heat Wireless Power System DC AC Tx Antenna Rx Antenna AC - DC System Efficiency η System η DC-AC Typical: X η Antenna-to-Antenna X η AC-DC Typical Impactful Areas: 1) FET s / IC 2) Design(k, Q), Tuning 3) Rectifier / IC 1)Equal Rectifier stage with Improperly Rx/Tx selected antenna makes the P/A work inefficiently thus heat & perceived poor performance 2) All Properly selected stages 1. η System (1) = 0.85 X 0.89 X 0.90 ~ 68% 2. η System (2) = 0.92 X 0.95 X 0.92 ~ 80%

7 One Circuit Design Adapts to Multiple Coil Sizes/Shapes Tuning & Matching Will Change TX Circuit (including Tuning / Matching) TX Antennas RX Antennas RX Circuit (Including Tuning / Matching) OR All Rx Functions on One Substrate

8 System Development Process Look for NC Standard Product Mechanical Simulation & Design Product Definition Fundamental System Analysis Iterative EM Simulation & Design Circuit Design & Simulation Production Yay! Design Validation Testing 8 Fabrication

9 Optimal Performance Modeling accelerates time to success EM Simulation & Design From EM Simulations Circuit Design & Simulation CONFIDENTIAL 9

10 Why Modeling Matters Time & Performance Improvements 80% Quality Factor Improvements of Actual Projects with NuCurrent Design / Technology in PCB VS other PCBs 70% 60% 50% 40% 30% 20% 10% CONFIDENTIAL 0% 10 A21-1 A21-2 Qi-PCB Rx Qi-FPC Rx Qi-FPC Rx Qi-Litz Tx Qi-FPC Rx AirFuel Tx Airfuel RX AirFuel Rx

11 Common Types of WPT Coil Materials Wire-wound Pros and Cons Cost Durability Tolerance / Variability Thickness Litz Wire-wound Traditional PCB Thermal Manufacturing / Repeatable Integration / Connection Ability to Meet Desired Performance NuCurrent MLMT Flex & PCB

12 Antenna-to-Antenna Efficiency Antenna Performance: Q s and k s Obtaining Optimal Performance Equal Performance Considerations Antenna Equations Variation of Efficiency with k and Q Optimal Systems FOM = κ 2 Q TX Q RX Eff = f (FOM) Q TX =90, Q RX =25 Q TX =300, Q RX =100 Design achieves higher coupling (k) CoolSkin Technologies TM delivers higher Quality Factor (Q) Typical operating point of loosely coupled applications (e.g. Resonant, Qi Friendly ) Coupling Coefficient, k - Typical operating point of tightly coupled applications (e.g. inductive)

13 Influencing Coil Selection: What IS Important? Use Case: Interoperability, Alignment, # of Simultaneous Devices, Charge Distance(z), Charging Rate & Power, Charge Location and Area(Tx) Your Environment Matters Your Product Inside & Out: Think Coil Volume & Surrounding Materials Battery / Other Active Electronics (Size Location) Which IC or Discrete Topology Thermal Budget Connection to the Main Board Size of Tx 13

14 Standard Product VS Custom Coil Price & Timing May Be Similar 1. Is there a standard coil that meets my mechanical needs for my allotted environment(l x W x H, main board attach, embedded)? Standard Coils: Good for Starter 2. Is there a standard product that will help me deliver the electrical performance that will please my end customers( power, efficiency, )? Create Your Own: Optimize Performance 3. Can I create - simulate a well functioning system on my own including Rx-Tx Pair? 14

15 Have I Selected the Proper Coil? Mechanical Perspective (1st) Electrical Perspective(2nd) Key Equations for Coil to Coil Efficiency and Mutual Inductance L Inductance ESR Equivalent series resistance Q = 2πfL ESR k = 1 L rx short L rx open k Coupling L rx short Inductance of receiver in stack-up with transmitter coil shorted L rx open Inductance of receiver in stack-up with transmitter coil open M = k (L Tx L Rx ) M Mutual Inductance L tx Transmitter inductance with stackup L Rx Receiver inductance with stackup Order (1) (2) (3) Eff Coil to Coil = κ 2 Q TX Q RX κ 2 Q TX Q RX 2 (4) CONFIDENTIAL 15 (5) Eff End to End = Eff Power Amp. Eff Coil to Coil. Eff Rectifier

16 Procedure For Calculating Efficiency Its Not Just About Efficiency Use Case Matters Measure inductance (L), equivalent series resistance (ESR) and quality factor (Q) of the TX coil with proper stack up (see Fig. 1) at desired frequency with an LCR Meter or Impedance Analyzer. Q is related to L and ESR through Eq. (1). Measure inductance (L), equivalent series resistance (ESR) and quality factor (Q) of the Rx coil with proper stack up (see Fig. 1) at desired frequency with an LCR Meter or Impedance Analyzer. Q is related to L and ESR through Eq. (1). Measure inductance (L) of Rx coil within the proper stackup at desired frequency with the transmitter coil terminations left open, record L rx open. Measure inductance of Rx coil within the proper stackup at desired frequency with the transmitter coil terminations shorted, record L rx short. Calculate k using Eq. (2) Calculate M using Eq. (3). Calculate Eff Coil to Coil using Eq. (4). Calculate Eff End to End using Eq. (5). CONFIDENTIAL 16

17 Thin Coil Provides Design Flexibility 3W Qi Solution Example- Performance Without Sacrifice Rx Coil Q Size L (uh) ESR (ohm) Total thickness Coupling Mutual inductance Efficiency (power) 3W Rx Wire Wound mm mm % (3W), 79.4% (2W) PNC01-R126W R mm mm % (3W), 78.7 % (2W) Measured at 100 khz Nucurrent coil is 56 % thinner than initial 3W Rx coil 3W Rx Coil PNC01-R126W R35 Thickness = 2.00 mm L= 6.24 uh ESR= 0.11 ohm Q= 34 Size = 30 mm OD 3W Tx Coil Stack Up Ferrite Rx coil Spacer Tx coil Ferrite Strictly Confidential

18 Medium Power 15 W Rx (Qi Portion of Tri-mode) 50 x 50 Flavor Comparison: NuCurrent Coils PCB Wire Wound 0.25mm Rx Coil : PNC11-R90L01E R35 L (uh) ESR (ohm) Q Coupling Mutual inductance (uh) 15W (12V) Peak Efficiency % 83.14% (13.86 W) Ant Ant Eff 92 % Stack Up Ferrite Rx coil Spacer (3 mm) Tx coil Ferrite Rx Coil : PNC11-R90L01E R70 18

19 Conclusion: Maximizing Performance: Be Hyper-sensitive to your environment Coil Selection is as critical as ICs, FETs and Rectifier NuCurrent Can Help: Magnetics Expertise to Full Systems 19