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Please critique my circuit

PLJackPLJack Posts: 398
edited 2004-10-16 18:22 in BASIC Stamp
Description:
I'm trying to design a digitally adjustable
voltage regulator that feeds redundant relays.

This is my first shot.
If someone could look it over I would very much
appreciate it.

Click here for circuit Image

The BS2 is powered normally, just not displayed on
this diagram.
Jack

Comments

  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2004-10-15 00:22
    Something looks odd with your wiper connection off of the digital pot... looks like this is going to ground.

    Also, I'm not sure if this matters, but I would connect the H terminal to vdd through a 1K rather than the L terminal.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Beau Schwabe - Mask Designer III

    National Semiconductor Corporation
    (Communication Interface Division)
    500 Pinnacle Court, Suite 525
    Mail Stop GA1
    Norcross,GA 30071
  • PLJackPLJack Posts: 398
    edited 2004-10-15 13:12
    Beau Schwabe said...
    Something looks odd with your wiper connection off of the digital pot... looks like this is going to ground.

    Also, I'm not sure if this matters, but I would connect the H terminal to vdd through a 1K rather than the L terminal.

    Hi Beau.
    I'm not surprised about the wiper.
    I basically substituted a LM317 POT circuit R2 with the DS1804.
    Not sure if that will work.

    What is the difference between the H and W terminal?

    Thanks
    Jack
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2004-10-16 18:22
    Yes, but in your circuit, W connects to ground and L connects to Vdd through a 1K resistor. The LM317 "sees" nothing but GROUND
    because you have a short in your schematic. Effectively the DS1804 is acting like a variable current source across the 1K resistor.

    Typically I think of the H terminal as the HighSide voltage source and the L terminal as the LowSide voltage source. In most cases
    this may not matter, but I would double check the specs just to make sure that H should not remain "more positive" than L at any
    given time. As I said this may not make a difference, it depends on the part number.

    -Beau Schwabe

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Beau Schwabe - Mask Designer III

    National Semiconductor Corporation
    (Communication Interface Division)
    500 Pinnacle Court, Suite 525
    Mail Stop GA1
    Norcross,GA 30071
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