AC SQUARE PULSE: 5-10 KHz 15 Amper 12-30 V

Discussion in 'The Projects Forum' started by m.majid, Jun 20, 2014.

  1. m.majid

    Thread Starter Active Member

    May 28, 2008
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    0
    AC SQUARE PULSE: 5-10 KHz 10 Amper 12-30 V

    Hi
    I need to make a circuit as follow:

    input:
    DC Square Pulse from MCU
    5-10 KHz (variable)
    5 V
    10 mA

    output:
    AC Square Pulse
    5-10 KHz
    12-30 V (power supply voltage)
    single power supply 12-30 V DC
    15 A

    [​IMG]

    could anyone help me ?
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,100
    3,036
    Use your MCU output to switch a logic-level power MOSFET.
    Is your 15A load purely resistive? If it has an inductive component, you'll need to protect the MOSFET from flyback.
    Your diagram shows a 60V output but your text says 30V. You need to sort that out.
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,789
    1,103
    Is the load ground referenced? If not, a full MOSFET bridge could give a 60V swing across a floating load.
     
  4. m.majid

    Thread Starter Active Member

    May 28, 2008
    39
    0
    i plan to use resistive load
    i have tried some H-bridge like below:

    http://forum.allaboutcircuits.com/attachment.php?attachmentid=69945&stc=1&d=1403275625

    but not succeed, at 1 amper load the mosfets become hot , and burn out
    on manual test (less than 1 Hz manual pulse) , it works nice: i see -30V on output when input is 0 V, and +30 V when input is 5 V
    but on any frequency 5 KHz -10KHz mosfets burn out
     
  5. m.majid

    Thread Starter Active Member

    May 28, 2008
    39
    0
    yes i mean floating load, reference is one of the outputs not circuit ground
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,100
    3,036
    Those gate resistors are probably slowing the turn-on and turn-off times, causing heating during switching. Can you supply more schematic details identifying the components?
     
  7. Experimentonomen

    Member

    Feb 16, 2011
    331
    46
  8. m.majid

    Thread Starter Active Member

    May 28, 2008
    39
    0
    Yeah seems something related to on/off delay of mosfets, causes a few micro seconds short circuit p-ch and n-ch mosfets
     
  9. m.majid

    Thread Starter Active Member

    May 28, 2008
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    0
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,789
    1,103
    To avoid prolonged FET switching times in the H-bridge, the FET gates need to be driven by low-impedance drivers, which also provide level-shifting to allow for control by 5V (or lower) logic. The drivers also need to set a dead-time to eliminate shoot-through from the upper to lower FET.
     
    m.majid likes this.
  11. Experimentonomen

    Member

    Feb 16, 2011
    331
    46
    As shown in my circuit.
     
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