Adjustable power supply using variable digital pot

Discussion in 'The Projects Forum' started by Tamilselvan, Jul 4, 2012.

  1. Tamilselvan

    Thread Starter New Member

    Apr 26, 2011
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    Hello all

    I have developed a adjustable power supply of range 0-120V. I used 10K ohm potentiometer to vary the output voltage, since I am about to replace the physical potentiometer with variable digital potentiometer. but in that case I dont know how to use the digital potentiometer in terms of programming, circuit designing.

    Pls guide to complete the project.
    Thanks in advance !!
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Firstly, make sure the current rating of the digital pot can handle the current demands of the circuit.

    Most digital pots require two control signals, CHIP SELECT and UP/DOWN.

    What is it you would like to know?
     
  3. Tamilselvan

    Thread Starter New Member

    Apr 26, 2011
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    How to program the pot, and what programming language should I go for ?
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    You can use any language you wish but first you have to tell us your platform.
     
  5. Tamilselvan

    Thread Starter New Member

    Apr 26, 2011
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    Sorry I cant able to understand ! what do u mean by platform ?
     
  6. t06afre

    AAC Fanatic!

    May 11, 2009
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    Have you selected the pot already? As MrChips say. It may be that you do not need any microcontroller at all. If that is wanted. I suggest you find out what kind of digital pots you can get your hand on. Then post the list here for further advice. Also if you will implement using microcontroller. Have you selected which brand/type you are going to use
     
  7. MrChips

    Moderator

    Oct 2, 2009
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    Tell us why you want to replace the pot with a digital pot.
     
  8. Tamilselvan

    Thread Starter New Member

    Apr 26, 2011
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    Hello Mr Chips
    Since I am trying to develop the power supply that can be to operate without manually tuning (ex :Manual potentiometer). I just want to drive my circuit using computer, lets say computer driven variable power supply. Thats y i choosed digital variable potentiometer.
     
  9. MrChips

    Moderator

    Oct 2, 2009
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    Ok. Next question is what kind of computer are you using?
     
  10. Tamilselvan

    Thread Starter New Member

    Apr 26, 2011
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    I am planning to use my laptop..
     
  11. t06afre

    AAC Fanatic!

    May 11, 2009
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    I am somewhat baffled. By how speedy the exchange of information is in this thread:eek:. And will the latter PC by any change have a serial port or be connected to an USB to serial port dongle. Or say a parallel port.
     
  12. MrChips

    Moderator

    Oct 2, 2009
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    This was intentional. I am trying to get the op to understand that we are not going to do the thinking for him/her.
    The op has obviously not thought through this very carefully. I can continue this charade for another ten or more questions. I will cut the chase.


    1. What kind of "laptop". What is the brand, model?
    2. What is the operating system?
    3. What is the version number of the OS?
    4. Does it have a serial, parallel or USB port? List all the ports.
    5. What program/app are you going to run in order to control the PSU?
    6. How is the voltage setting going to be entered? Number typed in? Up/Down buttons? Scroll bar?


    ... and still more to come.
     
  13. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    As MrChips said, provide as much details as possible.

    1. Do you really want to use a PC?
    2. Would a simple Up/Down button adjustment suffice?
    3. Do you need a display?
    4. What is the current/voltage rating for the pot? (depends on your circuit)
    5. Does the pot need to have memory, i.e. does it need to adjust to the same value after a power reset?

    There are several types of digital potentiometers, mainly they differ in steps available and interface, SPI, I2C, simple Up/Down & clock...

    If you had just a simple up down configuration with two buttons your circuit becomes much less complex.

    If you want to work with a SPI / I2C you can work with a uC which requires you to have some uC programming skills or you can work with a PC which also requires you to have programming skills (probably more than with just a PIC)

    an example: http://embedded-lab.com/blog/?p=2969
    another example: http://arduino.cc/en/Tutorial/SPIDigitalPot
    and another one: http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011862
     
  14. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    The circuit was alluded to but nobody asked the circuit to be shown. An usual initial request.

    0 to 120 V the OP said?

    DC, I guess...
     
    Last edited: Jul 5, 2012
  15. MrChips

    Moderator

    Oct 2, 2009
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    I guess we scared the op away.
     
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