0 - 5 vdc Ramp up Generator

Discussion in 'General Electronics Chat' started by Macka, May 3, 2012.

  1. Macka

    Thread Starter New Member

    May 3, 2012
    Hi Anyone

    I need to build a 0 to 5 Vdc Ramp-up Generator with adjustable Ramp up time. The unit needs to be resettable each time any selectable voltage is applied via switch (Push Button). The selectable switch inputs are 1, 2, and 4.5 vdc approximately and are also adjustable.
    If required there is a 24vdc supply available.
    In summary when each Input button is pushed for what ever the output voltage is selected then that voltage should be the reference maximum voltage for the Ramp Generator to achieve. In other words if I was to select say the Mid Range Switch (2 vdc) then the Ramp Generator would need to increase the ramp up voltage from 1 vdc to 2 vdc. Realising that the previous 1 vdc switch has already been applied.
    The unit needs to be sequential on each Push Button selection either increasing voltage or decreasing.
    I look forward to suggestions and circuit.
  2. jwilk13


    Jun 15, 2011
    I would use a microcontroller if it were me, but that's because I'm most familiar with those. I would get one with dedicated hardware PWM (like a PIC18F45K20).

    Are you familiar with using something like this? If so, I can give a "here's what I would do" rough description, but I don't want to explain something you're not familiar with.
  3. Bernard


    Aug 7, 2008
    Is a + 5V supply available?
    Switches are SP-ST-NO ?
    Does 0 V have a switch & does it also need to ramp down ?
    Approx ramp time ?
    What is max required output current ?
  4. strantor

    AAC Fanatic!

    Oct 3, 2010
    check out attachment
  5. Bernard


    Aug 7, 2008
    A quick outline of a possible solution: Selected SW is stored in R-S reg., Q out selects pre-programmed logic switch, LS. For simplicity only 4 bits shown.LS programmed with dip-switch 4 to 8 bits. A digital comparator looks at LS & UP-DN counter, directs count direction, or stops count if =. UP-DN C also feeds D to A converter. A buffer supplies required current.