Boost 12 V to 18 V

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dark_soul

New Member

• Jun 26, 2011

• #1

Hi, I have some troubles with my boost converter design, when I simulate the boost converter in orcad it's all ok, but when I assemble the circuit I have problems, the MOSFET it's heated a lot and there is a little buzz, I don't have idea what is the reason, I hope you can try to help me.

I Attachment a pdf file with some pictures that I hope can help you to know about my problem.

For all thanks.

 

Attachments

• Boost.pdf

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ronv

Well-Known Member

Most Helpful Member

• Jun 26, 2011

• #2

Are you sure your inductor is 7 MH. ?

 

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dark_soul

New Member

• Jun 26, 2011

• #3

Hi, thanks for the answer and yes, the inductor is 7mH, I measure with a LCR meter.

 

ronv

Well-Known Member

Most Helpful Member

• Jun 26, 2011

• #4

7 MH at one amp will be quite large. What is the maximum current spec and resistance of the inductor.

 

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Diver300

Well-Known Member

Most Helpful Member

• Jun 27, 2011

• #5

The waveforms with boost show that the MOSFET is not turning off cleanly. I think that you might have layout problems and that the switching spike that you get when the MOSFET turns off is somehow causing it to turn back on again.

 

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dark_soul

New Member

• Jun 28, 2011

• #6

Thanks for the answer, the inductor was done for me so I don't know what resistance it has, and for the current I don't think that I have problem.

This design is mounted on a protoboar, so what I need to do for turn off cleanly the Mosfet? do you saw my schematic, it's incorrect?

 

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MrAl

Well-Known Member

Most Helpful Member

• Jun 28, 2011

• #7

Hi,

Did you check the signal at Lin? See what that looks like. It could be getting feedback during turn off.

 

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dark_soul

New Member

• Jun 30, 2011

• #8

Hi, thanks for the answer, I have other question, it's necesary to have and independient sources? or I can feed all the circuit with a single source?

 

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MrAl

Well-Known Member

Most Helpful Member

• Jun 30, 2011

• #9

Hi,

If you need isolation you need different sources, but if they are all the same voltage and you dont need isolation you can usually use the same voltage source.

 

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dark_soul

New Member

• Jul 3, 2011

• #10

Thanks for the answer, now I'm using the 555 as a PWM generator, but see when I connect the output of 555 to IR2110 the signal is distorted I don't know why, will be damage the ir2110?, do you have some idea that what I need to do?. thanks