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Boost Converter (Read 4066 times)

bki

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Posts: 32

Boost Converter
Sep 01^st, 2014, 6:53am

Hi,

i have a regular Boost Converter with L=70uH, f=40k, Ron of MOSFET is 82 Ohm, Vin=5V, Vout=285V, Diode is DFLU1400. Duty Cycle=0.99 .
load capacitor is 5nF and load resistance is 5MOhm, therefore output current is 57uA. Operating in DCM.

I calculate the power efficiency through: Vout*Iout/Vin*Iin.
I receive Iin through integrating the input current over 1 Period and divide it by the Period.

The result for power efficiency that i receive lies below 1%. I am wondering what is the reason why the power efficiency is so bad?
Can i do anything to increase the efficiency?

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A Kumar R Community Member Offline Posts: 72 India	Re: Boost Converter Reply #1 - Sep 2^nd, 2014, 4:11am Hi, A rough calculation showed me that it is around 57%. Vout = 285 V & Iout = 57uA Vin = 5 V & Iin = 57uA/(1-0.99)--your D is 0.99 and therefore Iin = Iout/(1-D). --Anil Reddy
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bki Community Member Offline Posts: 32	Re: Boost Converter Reply #2 - Sep 2^nd, 2014, 7:49am I also calculated this. But this is not the result i get, if i simulate it. My Iin lies at around 370mA in this case with D=0,99 f=40k. (Calculated value would be 5,7mA) What can be the reason for the discrepancy?
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A Kumar R Community Member Offline Posts: 72 India	Re: Boost Converter Reply #3 - Sep 2^nd, 2014, 10:19am Hi, I suspect the set-up of simulation. Your simulation set-up is taking 1.85 watts of power from the input and giving out only ~16mW, which is, of course, can't be true. --Anil Reddy
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