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 Well-Known Member

    May 28, 2008
    51
    3
    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
    13,612
    4,412
    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
    7,098
    1,480
    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 Well-Known Member

    May 28, 2008
    51
    3
    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 Well-Known Member

    May 28, 2008
    51
    3
    yes i mean floating load, reference is one of the outputs not circuit ground
     
  6. wayneh

    Expert

    Sep 9, 2010
    13,612
    4,412
    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 Well-Known Member

    May 28, 2008
    51
    3
    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 Well-Known Member

    May 28, 2008
    51
    3
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    7,098
    1,480
    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.
     
Loading...