Diodes purpose in this circuit?

Discussion in 'Digital Circuit Design' started by re4mat0r, Aug 17, 2016.

  1. re4mat0r

    Thread Starter New Member

    Jun 21, 2016
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    Hi. All sense pins in this schematic are used with diodes. Anyone can explain? And what diodes will work here. No info in datasheet.

    [​IMG]

    Thanks,
    Roman
     
  2. dannyf

    Well-Known Member

    Sep 13, 2015
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    To clamp the input.
     
  3. re4mat0r

    Thread Starter New Member

    Jun 21, 2016
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    And what about the ratings of the diode? Anything will work here?
     
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Any clue what PVDD is, or is that a secret?

    The resistor divider on each SENSE is about 8:1, so a SWAG is a 3.3 V CPU and a 24 V input. Since the source impedance is around 35K, spike transient currents are in the low mA range. My guess is that any small signal Shottkey diode will work, maybe something in the BAS series.

    ak
     
  5. re4mat0r

    Thread Starter New Member

    Jun 21, 2016
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    Great, thanks. PVDD is the battery + here.
     
  6. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The number of volts ... ?
     
  7. re4mat0r

    Thread Starter New Member

    Jun 21, 2016
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    24V if you are using a battery with that voltage. It is the main power supply you are using with your motor and driver.
     
  8. dannyf

    Well-Known Member

    Sep 13, 2015
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    The spec for the diode will depend on what kind of source you are dealing, specifically voltage swings and output impedance.

    The lack of a serial resistor in front of the diodes suggest the sources are fairly week.
     
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