RC clen v buck menici

[hwnews konference]

Uz jsem nasel dalsi pojednani i s peknymi obrazky
https://www.fairchildsemi.com/application-notes/AN/AN-4162.pdf

2016-07-22 9:42 GMT+02:00 Miroslav Waldecker <miro.waldecker na gmail.com>:

> Priamo sa snubber počítať dá iba veľmi približne. Treba merať a laborovat,
> pretože vplývajú na to všetky parazitické komponenty vrátane pcb. Závisí od
> toho, kde je problém. Frekvenciu zmerate priamo v uzle kde je zapojený.
> Vyzerá to ako oscilácie pri zapnutí/vypnutí záťaže a tie majú nejakú
> vlastnú frekvenciu. Takže osciloskopom.
>
> M.
>
> Dňa 22. 7. 2016 9:33 používateľ "hwnews konference" <hwnews na cncnet.info>
> napísal:
>
> jojo ten pojem jsem znal respektive znam - hlavne pri pouziti s triakem
>>
>> nasel jsem tenhle dokument od TI
>> http://www.ti.com/lit/an/slyt465/slyt465.pdf
>>
>> The procedure for choosing the capacitor and resistor components starts
>> with measuring the ringing frequency of the original circuit. Once the
>> frequency is determined, a capacitor is put in parallel with the low-side
>> FET to change the ringing frequency to half the original value. When the
>> frequency is half the original value, the parallel capacitor is equal to
>> three times the parasitic capacitance of the original circuit. With the
>> capacitance and frequency known, the parasitic inductance can be calculated
>> by using the formula f ½ LC = π , where f is the original ringing frequency
>> and C is the parasitic capacitance. The resistor to critically damp the
>> circuit is calculated from the equation R L/C = . This resistor may or may
>> not provide the necessary ringing reduction. Increasing the resistance
>> results in an underdamped system, which allows more ringing but decreases
>> power dissipation. Increasing the capacitance reduces the ringing but
>> increases power dissipation. For the example, using a 2200-pF capacitor and
>> a 1-W resistor reduced ringing to 19.1 V.
>>
>> Ale moc z toho moudrej nejsem...jakym zpusobem mam zmerit ty zakmity.
>> Respektive jak by mely vypadat nebo kde je uvidim a jak urcim jejich
>> frekvenci?
>>
>>
>> Dne 22. července 2016 9:14 Jan Waclawek <konfera na efton.sk> napsal(a):
>>
>>> Prakticke skusenosti nemam bo sa vykonovej elektronike vyhybam, ale
>>> klucove
>>> slovo (trebars do guglu) je "snubber" a dovodom je potlacenie prekmitov
>>> sposobenych parazitickymi RLC obvodmi.
>>>
>>> JW
>>>
>>>
>>> ----- Original Message ---------------
>>> >Zdravim,
>>> >
>>> >je mi nekdo schopen vysvetlit proc se tento clen zapojuje na stred
>>> mustku
>>> >(respektive paralelbne s dolnim tranzistorem nebo diodou)?
>>> >
>>> >Jakou tam mam funkci a jak spravne spocitat jeho hodnoty?
>>> >
>>> >RV
>>>
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>>
>>
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