Low AC and DC Resistance Inductor Technology Weyman Lundquist – President and CEO West Coast Magnetics April 4, 2007 International Patent # WO 2005/09630

Patented Inductor Technology Very Low DCR, High Window Utilization Foil winding AND Low AC Resistance AC loss reduction comparable to litz wire SIGNIFICANTLY LOWER TOTAL LOSSES Applies to: Gapped core structures Idc > 10 amps Ripple > 5% Inductors (Chokes)

West Coast Magnetics is: A Manufacturing Driven Organization Lean since % on-time delivery 100% defect free product A Customer Driven Organization Service Engineering Support A Technology Innovator

West Coast Magnetics Company History Founded in 1976 in Silicon Valley Present Ownership 1993 Open Stockton facility in 1996 Acquired Mexico Facility in 1999 New Inductor Technology 2003

Company Overview Stockton, CA Corporate Headquarters and Manufacturing Facility Tecate, MX Production Facility Custom and Standard Products Power Transformers: 50/60 Hz to MHz Power Transformers: 1 Watt to 15 kW Power Inductors to 200 amps Common Mode Chokes to 200 amps Current Sense Transformers 60 Hz to MHz RF Inductors to 100 MHz

How Does it Work? By cutting away a section of the foil winding in the region of the core gap winding eddy currents are concentrated locally in the region of the cutaway.

Experiment: Is the New Technology Really Better? Objective: A Conclusive Comparison of the New Technology to Conventional Windings Step 1: Define the Inductor Inductance 90 uH Current 40 Adc Ripple: Triangle wave at 50 kHz Core: E70/33/32 Epcos N67 material Gap: 2.64 mm (1.32 mm each center leg) Turns: 15

Experiment: Is the New Technology Really Better? Step 2: Wind Inductors with Conventional Windings Using Best Practices Full window Single layer Step 3: Determine Winding Losses for each Inductor as a Function of Ripple Magnitude Step 4: Compare Results to Temperature Rise Data Collected under Load.

Winding Cross Sections 20/32 Litz Solid Wire 400/40 Litz Full Foil Long Cut 50/40 Litz Prototype Cut Solid Wire20/32 Litz

Method of Estimating Losses DCR – Measure voltage drop under 5 Amp DC load. Core Losses: Derived from Epcos loss curves. AC resistance – Sweep from 10 kHz to 200 kHz with Agilent 4294A network analyzer Use Fourier decomposition to translate sinusoidal sweep data to triangular waveform

Total Loss Comparison

Temperature Rise Measurement – Test Set Up 40 A 20 uF 10 Ohms 2.5 Ohms Amplifier Output: 6A P-P Function Generator Device Under Test 90 uH

Temperature Rise Measurement – Results at 15% Ripple

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Design Tools Code for Winding Loss Simulation Code for Translation of Winding Cross Section into 2D Foil Shape Code for Prediction of H vs. L vs. Gap for any Inductor

Licensing Opportunity Objective: The widest possible application of the technology. Develop tools for design support. Maintain license rate at a level which will lead to widespread use. Contact: Weyman Lundquist

Thank you for your time Weyman Lundquist, President West Coast Magnetics 4848 Frontier Way, Ste 100 Stockton, CA