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The Power Advantage Educational Program

Whiteboard: A New Way to Simplify Power Chain Analysis

Sean Crilly, VP VI Chip Design Engineering10 April 2014

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Introduction

› Designing Power Systems:

– Traditional Approach.– Powerbench Solution Selector / Whiteboard approach.

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The Process› Define the solution needed.› Choose the best fit components.› Estimate performance.

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Finding Efficiency from Data Sheets

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Finding Efficiency› Each Buck Regulator:› Output Power = 3.3V x 9A = 29.7W› Input Power = 29.7W / 0.92 = 32.28W› Efficiency = 29.7 / 32.28 = 92%› Power Loss = 32.28W – 29.7W = 2.58W› Input Current = 32.28W / 30V = 1.076A

› Therefore the output current of the PRM will be:– 4A + 1.076A + 1.076A = 6.152A

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› PRM Efficiency:– Given that we are using a 30V output and assuming that it is linear:– 97% – 94.5% = 2.5% (efficiency at 55V – efficiency at 20V)– 55V – 20V = 35V– Change per volt = 2.5% / 35V = .0714%– Efficiency at 30V = 94.5% + (.0714 x 10) = 95.214%› Input Power to the PRM:– Output Power = 30V x 6.152A = 184.56W– Input Power = 184.56W / 0.95214 = 193.83W– Power Loss = 193.83 - 184.56 = 9.27W– Input Current = 193.83W / 48V = 4.038A

› System Efficiency = (Output Power / Input Power) x 100– Output Power = Power Delivered to the Loads = (30V x 4A) + (3.3V x 18A) = 179.4W– Input Power = Power sourced by supplies = (48V x 4.033A) = 193.83W

– Estimated System Efficiency = 92.55%

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Efficiency Curves

› Efficiency / Power dissipation is a function of

Line/Load and Temperature– Sample produced by Vicor

Design Characterization ATE:

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On-Line Simulator› Simulator can help on a model by model basis.

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A better way… Vicor Whiteboard

› Defined as:

“An on-line tool to design and analyze power systems with the appropriate set of Vicor power conversion components”

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› The more accurate and actual efficiency produced by the Powerbench Whiteboard is 93.17% (and is generated

automatically in milliseconds):

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Let’s try it….

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Questions ?

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Go tohttp://www.vicorpower.com/powerbench-1

to access the online tools

Thank you for watching