Voltage Regulator Internal Circuit

Discussion in 'General Electronics Chat' started by Engr, Aug 15, 2010.

  1. Engr

    Thread Starter Member

    Mar 17, 2010
    114
    5
    Hi Guys,

    Can someone tell me what is inside a Voltage Regulator IC. I am trying to understand how a voltage regulator IC does the voltage regulation that is why I need to know what is inside a Voltage Regulator IC.

    Thanks and Best Regards,
    Engr
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Have you a particular voltage regulator in mind? I would suggest consulting the manufacturer's datasheet. They are usually pretty good at providing an equivalent internal circuit schematic.

    hgmjr
     
  3. Engr

    Thread Starter Member

    Mar 17, 2010
    114
    5
    What I have in mind are the 78XX Series and 79XX Series Voltage Regulator. Your right, they are really good at it but I doubt if they are going to give an equivalent circuit of their own products.. But still, I am going to try it..
     
  4. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Engr likes this.
  5. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    It has a voltage reference, a high gain error amplifier and a series pass transistor. It has a current limiting circuit. It also has a circuit that detects that it is too hot and shuts it down until it has cooled.

    If the output voltage is too low then the error amplifier senses that the output is lower than the reference voltage so it turns on the series pass transistor harder to raise the output voltage.
    If the output voltage is too high then the error amplifier senses that the output is higher than the reference voltage so it turns on the series pass transistor less or turns it off to reduce the output voltage.
     
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