Parallel MOSFETs

Discussion in 'General Electronics Chat' started by Rmauser, Aug 13, 2013.

  1. Rmauser

    Thread Starter New Member

    Feb 12, 2013
    4
    0
    Hello! I'm planning to parallel two TPS27081A high-side PFET switches to increase current throughput and decrease overheating that I'm experiencing at higher loads with just one switch. Is it okay to share the 10k pull-up resistor R1 between the two switches (space is extremely limited and my resistor array is used up) and also share the single logic line used to control the original single switch? Any special things I need to consider when paralleling two of these switches for power control (one output). Thanks for any help as I'm quite new to this!
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,123
    3,047
    There needs to be resistance between the two gates, to damp any LC ringing between them. Something like 100Ω on each gate is often seen.
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,854
    767
    Two TPS27081A in series with a 0.1Ω/5W or 0.2Ω/5W then in parallel.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You haven't posted your circuit, nor said what it's purpose is. Without such information, it's difficult to determine what the actual cause of your P-ch MOSFET getting hot actually is; however using a single 10k resistor to turn the MOSFET off will mean a slow turn-off, and plenty of power dissipation.

    If you post your complete circuit, you will get better feedback as to how you might fix the actual problem.

    If your gate control circuitry is not adequate, adding a 2nd MOSFET will not help the situation.
     
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