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Voltage drop of LM2577S supply

attila turgut
Prodigy 50 points
Part Number: LM2577

Hello Im using LM2577S ADJ for powering my ESP12E wifi module.before hook up the LM2577(My connection12v 1A adaptor---LM2577S---ESP12E) , I adjusted it Vout=3.3. When I connected LM2577S and ESP12E. Voltage dropped approximately 200-300mV.When I used Vout=3.3 adaptor instead of LM2577. And  I again saw same voltage dropping. How can ı solve it? my picture GPIO0 Connected Vcc with 10k

And last question is related to bottom two picture..This two breadboard  "V" and "GND" connected each other breadboard .I just changed multimeter GND connection place Why the two measurement different? This board works 3.3 (Vsupply(max)=3.6v) but why ı read 1.5 v?When I used Vout=3.3 300mA adaptor instead of LM2577 I again saw 1.5v between ESP12E Vcc and GND

  • 0
    TI__Guru 57555 points

     The LM2577 is a boost regulator; so I am not sure how you are converting from 12V to 3.3V ?? Unless you are using a fly-back ??

    It looks like you are using some kind of regulator module, from you photo.  You may need to talk to the

    people that created that module.

    In general it is not a good idea to use a "white breadboard" for proto-builds with switching regulators and their loads.

    It sounds like you are getting a large voltage drop from the bread-board and the small wires you are using.

  • 0 in reply to Frank De Stasi
    Prodigy 50 points
    I dont find any schematics.I buy it from aliexpress headline "DC-DC Auto Boost Buck Step Up Step Down Converter Module". Hımm. When i used it with 12v input to 3.3v output,I heard same kind of sound
    0)reason of voltage drop just related to white-breadboard? Is it related to wrong using of modul?
    1)I use it act as buck convertor Is it corrupted? And flyback converter can be only used step up. Isn't it?
    2)Can you advice me any converter that I can use it both boost and buck converter?
    3)How to I prototype SMPS ?
  • 0 in reply to attila turgut
    TI__Guru 57555 points

    If all you need is 12V to 3.3V, then a simple LDO or buck regulator should be OK.  Since you do not have experience with SMPS, you may

    want to go with a simple LDO.  I do not know how much current you need, however TI has a wide selection of LDOs to choose from.

    If your input voltage will go above and below your output (3.3V), then you will need a buck-boost regulator.  In that case, it would be best to

    find a finished module online.

    In any case, I would connect the load directly to the regulator with soldered wire leads, rather than the bread-board.