Adjustable power supply using variable digital pot

Thread Starter

Tamilselvan

Joined Apr 26, 2011
8
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 !!
 

MrChips

Joined Oct 2, 2009
19,747
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?
 

t06afre

Joined May 11, 2009
5,934
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 !!
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
 

Thread Starter

Tamilselvan

Joined Apr 26, 2011
8
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.
 

MrChips

Joined Oct 2, 2009
19,747
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.
 

praondevou

Joined Jul 9, 2011
2,942
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
 

atferrari

Joined Jan 6, 2004
3,577
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...
 
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