H bridge P channel and N channel

Discussion in 'General Electronics Chat' started by Skubby SkinnyChubby, Jul 7, 2015.

  1. Skubby SkinnyChubby

    Thread Starter New Member

    Jun 19, 2015
    25
    1
    Hi,
    i know that i can design a H bridge using 2 p channel MOSFET and 2 N channel MOSFET or 4 N channel MOSFET. (Image attached)

    Q1. what's the difference of using 2 p channel MOSFET and 2 N channel MOSFET or 4 N channel MOSFET to design a H bridge?
    Q2. can i use 4 P channel MOSFET to design my H bridge?

    Thanks guys :)
     
    • 1.png
      1.png
      File size:
      63.2 KB
      Views:
      12
    • 2.png
      2.png
      File size:
      7.1 KB
      Views:
      13
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,010
    3,784
    Standard N-channel MOSFETs gates should be driven 10 volts above the source. Difficult to do that when they are the high-side of the H bridge. If you are making an H bridge with 4 n-channel MOSFETS, then you need gate drivers with charge pumps that can provide a voltage above the source.

    You can make an H with 4 p channel but standard p-channel needs 10 volts below the source. P-channel mosfet driver chips are available. N-channel MOSFETS are generally faster and lower on-resistance and cheaper than the P-channel mate. Therefore, using 4-n-channel is more desirable than 2p and 2n in some applications. There is just no technical benefit of using 4-p channel.
     
    Skubby SkinnyChubby likes this.
  3. camerart

    Active Member

    Feb 25, 2013
    517
    30
    Hi Skubby,

    I've been using this H-bridge. It runs from 12V and drives 12V motors ~2A.

    Camerart.
     
    Skubby SkinnyChubby likes this.
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    An example of a good H-Bridge...

    Independent control of all four FET gates so non-overlapping gate signals are controlled by software (good).
    PFETS are driven with a full -12V gate drive (good).
    NFETS are driven only the port voltage (bad, unless the NFETS are logic-level gate drive, and the micro is running on 5V).
     
    Skubby SkinnyChubby likes this.
  5. camerart

    Active Member

    Feb 25, 2013
    517
    30
    Hi,

    I just checked the NFET PDF Rds on. 3.7A @ 4.5V and 7.3A @10v.

    C.
     
    Skubby SkinnyChubby likes this.
Loading...