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PCB with 30A current

Discussion in 'PCB Layout, Design and Manufacture' started by jacklam2048, Feb 22, 2021.

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  1. jacklam2048


    Feb 22, 2021
    I am a new comer in making PCB design. In the moment, I am trying to make a PCB with a MOSFET to control a 12V, 30A current which is supplying power to 6 x TEC1-12706 peltier cooler (@ peltier cooler consumes 5A current). My question is what is the best way to create the copper trace for this 30A current ? If I follow the rule of 1A corresponding to 1mm wide copper trace, the copper trace will be very wide.
    1. Should I use copper pour to make the top layer for the +12V, 30A current, and with another copper pour in the bottom layer for the ground ?
    2. or should I create a 4 layers PCB with the 2nd and 3rd layer for the +12V, 30A and the ground of the MOSFET ?
    or any other method to deal with this ?
    Please see the part enclosed by the red dash line in the attached image which is the 12V, 30A issue I mentioned. Thank you very much !

    Attached Files:

  2. Harald Kapp

    Harald Kapp Moderator Moderator

    Nov 17, 2011
    Use any of the pcb trace width calculator tools to calculate the minimum requirements. This is but one example.
    Use as much copper as possible. If you can use a 4 layer PCB, use 2 layers each for power and ground. Minimizing the impedance is of the essence.
    Keep logic ground and power ground separate with only a single connection at the MOSFET's source. This is called a star point and is meant to minimize the feedback from the voltage drop across the power ground into the digital ground. See this reference (which is for connecting analog and digital grounds but has the same background).
    I'l try to indicate what I mean graphically (note that I removed the GND symbol from CN11):

    You may also keep the high current traces free from solder stop and add additional tinning instead to further reduce the impedance
  3. jacklam2048


    Feb 22, 2021
    Hi Harald,
    Thank you very much for your reply. Your information and advice help me a lot! I will try to follow your instructions to modify the PCB design and layout. Thanks again !
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