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What happens if schottky diode is replaced by general purpose diode?

Hi all,

I've uploaded one schematic.. please go through the attachment. My question is:
In the schematic, to the VDD pin of the IC, diode D2 is connected which is of schottky type. what happens if general purpose rectifiers like 1N4007 is used in that place? what is the purpose of using diode D2 in that place.. Can anyone tell me please.?

Replies

  • Scorpion007
    Scorpion007
    may be it is concerning with frequency of current because Schottky diode design to work in high frequency current ( even 300 Mhz frequency) but normal PN junction diode do not works in high frequency. It is my opinion.
  • Shyamsundar
    Shyamsundar
    Scorpion007
    may be it is concerning with frequency of current because Schottky diode design to work in high frequency current ( even 300 Mhz frequency) but normal PN junction diode do not works in high frequency. It is my opinion.
    ok, but why diode is needed in that place?
  • Harshad Italiya
    Harshad Italiya
    Shyamsundar
    ok, but why diode is needed in that place?
    As said by #-Link-Snipped-# its for high frequency purpose as schottkey diode can response on high frequency another reason is to prevent the supply goes back to mains. As diode cathode is connected to VDD it will give you provision to do not flow voltage in reverse direction.
  • rikil
    rikil
    Technically, Schottky diode has very low reverse recovery time as compared to normal rectifier diode. Your circuit, which I suppose is SMPS, works on may be more then 500Khz. So in that case at switching side Schottky diode is needed. If you see, on power side, normal diode is used.
  • Shyamsundar
    Shyamsundar
    rikil
    Technically, Schottky diode has very low reverse recovery time as compared to normal rectifier diode. Your circuit, which I suppose is SMPS, works on may be more then 500Khz. So in that case at switching side Schottky diode is needed. If you see, on power side, normal diode is used.
    SMPS operating frequency is 115kHz, What is the output response if it is replaced by power diode?
  • [Prototype]
    [Prototype]
    Shyamsundar
    SMPS operating frequency is 115kHz, What is the output response if it is replaced by power diode?
    Simply speaking, your SMPS will fail because normal diode won't be able to switch in the given required time. Now with fail, I don't mean it'll not start. It will just produce a unreliable output with glitches. Not to mention, the diode will burn eventually after sometime. If you place a higher rating diode, it won't burn, but still the output will be distorted.
  • Jeffrey Arulraj
    Jeffrey Arulraj
    Shyamsundar
    SMPS operating frequency is 115kHz, What is the output response if it is replaced by power diode?
    Schottky is famous for its switching speed try to use it diodes even very fast diodes have high response time which will not support 115kHz any time so it is a poor choice you are making if you swap your schottky
  • arunchary
    arunchary
    surge current concept is not holds good normal diode compared to schottky diodes...and as well as higher amount of currents can be applicable in this type only with higher frequencies .
  • sangram shelake
    sangram shelake

    I used fast switching response diode which is taken from Crt TV main board in the place of one of two shottky barriers diode at the secondary side of 13v DC output smps of led TV power board and it became successfully gives 13v DC output.


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