Driving a 12V 6A Motor with a 5V signal

Discussion in 'The Projects Forum' started by mcikegami, Dec 26, 2010.

  1. mcikegami

    Thread Starter New Member

    Dec 26, 2010
    Hey all,
    I'm a junior in high school building an ROV for the MATE ROV competition with a amateur robotics team this year. For this year's competition, we've decided to control our bot via an Arduino Mega, and we're using PWM to potentiate the thrusters. As the person designated to electrical, I fortuitously have no idea how to set up an intermediate step from the Arduino to our thrusters. I've looked into H-Bridges with both Relays and Transistors, and defaulted to the transistor. How would I choose what transistor to use though? I've tried several (all BJTs) and they're giving me nothing but problems. Should I switch to a FET? Should I use a P type and an N type, or only one? Should I use a dedicated transistor to control the Hbridge? What specs should I purchase them with? Do I ask too many questions? Help!

    (I'm trying to control a 12V 6A motor with a 5V Pwm signal. Thanks!)
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010

    mosfet's are a perfect fit for your puposes. BJT and IGBT have their places but as you discovered can be harder to design with.

    The link should give you lots of stuff to read and hopefully a few ideas as well.
  3. mcikegami

    Thread Starter New Member

    Dec 26, 2010
    That's what I thought... do you have any particular ones in mind? And can I keep the 5v signal? Or should I run it through an intermediate transistor?
  4. SgtWookie


    Jul 17, 2007
    I don't know what your lead time for acquisition is. End of February next year OK?

    These: http://www.pololu.com/catalog/product/705
    are pretty nifty. However, ST Microelectronics seems to have a backlog on the VNH2SP30x/VNH3SP30x IC's, and no authorized distributor has any in stock.

    You might build something out of discrete components, but it'll be really tough to get the same kind of functionality in the footprint these controllers have.

    If you try to buy one of the ICs from a source that isn't an authorized distributor, you're likely to get a counterfeit part.
  5. hgmjr

    Retired Moderator

    Jan 28, 2005
    Digikey has the h-bridge devices (TLE5206-2S) that should make your motor driver design considerable easier to build. You should be able to use two of these. The input control signals are ttl/cmos compatible so you will be able to use your +5 volt signals directly into this device. It is throughhole so you will not have a lot of trouble using soldering into your prototype board. It is capable of 6A peak which is consistent with your motors.

    Be sure to make room for a heatsink just to be on the safe side.

  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009

    MATE Details for 2010

    Is your ROV to be tethered? What size will it be, and the power sources for the motors? These get complicated quickly.