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Re: Need suggestions for a motor control chip

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  • yellowlaser
    Update: I managed to get something working last night. Turns out I had three cascading problems that prevented the transistor/FET method from working. I
    Message 1 of 13 , Oct 1, 2009
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      Update:

      I managed to get something working last night. Turns out I had three cascading problems that prevented the transistor/FET method from working.

      I controlled a 2n2222 transistor from the micro. The 2n2222 switched the raw system voltage (~9 volts) used to control the gate of the FET. This was enough voltage to turn on the FET. Works well at 20KHz.

      I still do not like the solution due to the extra parts and would still love a suggestion for a good part.

      -Skye Sweeney

      --- In SeattleRobotics@yahoogroups.com, FLL-Freak <fll-freak@...> wrote:
      >
      >
      >
      > I am interested in controlling a 5 volt 1 amp  DC brushed motor using 3.3V logic. I would like speed control via PWM but do not need to reverse direction. I am thinking a full h-bridge is an overkill. A simple FET/switch/ 'thing' must exist to do this!
      >
      >
      >
      > I have been playing with varius MOSFETS and found that they need more than the 3.3 volts I have from the micro to turn them on. I have a tube of IRLD024 logic level FETS, but they are 5 volt logic not 3.3. I can't seem to find a similar part for 3.3 volt logic.
      >
      >
      >
      > I tried using an NPN transister to switch a higher control voltage to the FET, but for whatever reason that does not seem to work. It also increases the part count considerably.
      >
      >
      >
      > I have tried some Avago solid state relays such as the ASSR-1511 but found the switching speed is very limited (about 2K Hz). I would at least like to modulate the motor outside of hearing range (> 18KHz).
      >
      >
      >
      > I have done a fair amount of poking around, but can't find the right key words to find a suitable part. Any suggestions would be most welcome.
      >
      >
      > -Skye Sweeney
      >
    • Thomas D. Dean
      ... Controller board using the mc33887. http://www.pololu.com/catalog/product/712 Tom
      Message 2 of 13 , Oct 1, 2009
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        On Thu, 2009-10-01 at 12:34 +0000, yellowlaser wrote:

        > I still do not like the solution due to the extra parts and would still love a suggestion for a good part.

        Controller board using the mc33887.

        http://www.pololu.com/catalog/product/712

        Tom
      • dcwjobs2004
        I understand you are using a 5V motor, which means a 5V power supply. Here is a thought for your situation. Use an ordinary 5V CMOS logic chip, such as a
        Message 3 of 13 , Oct 1, 2009
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          I understand you are using a 5V motor, which means a 5V power supply. Here is a thought for your situation. Use an ordinary 5V CMOS logic chip, such as a 74ACT244 or 74ACT04. You can drive these with 3.3V logic, and they will have the 5V swing you need to drive the logic MOSFETs. You run the drivers off the 5V supply.

          The 74ACT series will give you good transient current drive to the high input capacitance (~1000 pF!) MOSFETs so they will turn on and off quickly. The 74ACT244 is a non-inverting octal driver (drives 8 FETs) in a 20 pin package, and the 74ACT04 is six inverters in a 14 pin package. Pretty much anything in the ACT series will work. The "T" of the ACT means that it takes a TTL level input with threshold of ~1.4V.

          Dave Wyland

          --- In SeattleRobotics@yahoogroups.com, "yellowlaser" <fll-freak@...> wrote:
          >
          > Update:
          >
          > I managed to get something working last night. Turns out I had three cascading problems that prevented the transistor/FET method from working.
          >
          > I controlled a 2n2222 transistor from the micro. The 2n2222 switched the raw system voltage (~9 volts) used to control the gate of the FET. This was enough voltage to turn on the FET. Works well at 20KHz.
          >
          > I still do not like the solution due to the extra parts and would still love a suggestion for a good part.
          >
          > -Skye Sweeney
          >
          > --- In SeattleRobotics@yahoogroups.com, FLL-Freak <fll-freak@> wrote:
          > >
          > >
          > >
          > > I am interested in controlling a 5 volt 1 amp  DC brushed motor using 3.3V logic. I would like speed control via PWM but do not need to reverse direction. I am thinking a full h-bridge is an overkill. A simple FET/switch/ 'thing' must exist to do this!
          > >
          > >
          > >
          > > I have been playing with varius MOSFETS and found that they need more than the 3.3 volts I have from the micro to turn them on. I have a tube of IRLD024 logic level FETS, but they are 5 volt logic not 3.3. I can't seem to find a similar part for 3.3 volt logic.
          > >
          > >
          > >
          > > I tried using an NPN transister to switch a higher control voltage to the FET, but for whatever reason that does not seem to work. It also increases the part count considerably.
          > >
          > >
          > >
          > > I have tried some Avago solid state relays such as the ASSR-1511 but found the switching speed is very limited (about 2K Hz). I would at least like to modulate the motor outside of hearing range (> 18KHz).
          > >
          > >
          > >
          > > I have done a fair amount of poking around, but can't find the right key words to find a suitable part. Any suggestions would be most welcome.
          > >
          > >
          > > -Skye Sweeney
          > >
          >
        • Chris Baron
          Try the TLE5206 from Infineon. It will work within the parameters you state. It is a single chip H-bridge in TO-220-7. I think Digikey has them in singles.
          Message 4 of 13 , Oct 1, 2009
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            Try the TLE5206 from Infineon. It will work within the parameters you state. It is a single chip H-bridge in TO-220-7. I think Digikey has them in singles.

            Chris

            > Posted by: "yellowlaser" fll-freak@... yellowlaser
            > Date: Thu Oct 1, 2009 5:35 am ((PDT))
            >
            > Update:
            >
            > I managed to get something working last night. Turns out I had three cascading problems that prevented the transistor/FET method from working.
            >
            > I controlled a 2n2222 transistor from the micro. The 2n2222 switched the raw system voltage (~9 volts) used to control the gate of the FET. This was enough voltage to turn on the FET. Works well at 20KHz.
            >
            > I still do not like the solution due to the extra parts and would still love a suggestion for a good part.
            >
            > -Skye Sweeney
          • Peter Harrison
            How about the Vishay Si9986?
            Message 5 of 13 , Oct 1, 2009
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              How about the Vishay Si9986?


              On 30 Sep 2009, at 17:53, FLL-Freak wrote:

              >
              >
              > I am interested in controlling a 5 volt 1 amp DC brushed motor
              > using 3.3V logic. I would like speed control via PWM but do not need
              > to reverse direction. I am thinking a full h-bridge is an overkill.
              > A simple FET/switch/ 'thing' must exist to do this!
              >
              > I have been playing with varius MOSFETS and found that they need
              > more than the 3.3 volts I have from the micro to turn them on. I
              > have a tube of IRLD024 logic level FETS, but they are 5 volt logic
              > not 3.3. I can't seem to find a similar part for 3.3 volt logic.
              >
              > I tried using an NPN transister to switch a higher control voltage
              > to the FET, but for whatever reason that does not seem to work. It
              > also increases the part count considerably.
              >
              > I have tried some Avago solid state relays such as the ASSR-1511 but
              > found the switching speed is very limited (about 2K Hz). I would at
              > least like to modulate the motor outside of hearing range (> 18KHz).
              >
              > I have done a fair amount of poking around, but can't find the right
              > key words to find a suitable part. Any suggestions would be most
              > welcome.
              >
              > -Skye Sweeney
              >
              >
              >
            • Tony Mactutis
              Skye, Fairchild makes lots of mosfets that will work at 3.3v. Here are a couple: NDS8434 (p-channel) FDN337N (n-channel) To find them, go on digikey and
              Message 6 of 13 , Oct 1, 2009
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                Skye, Fairchild makes lots of mosfets that will work at 3.3v. Here are
                a couple:

                NDS8434 (p-channel)
                FDN337N (n-channel)

                To find them, go on digikey and search for 'logic level mosfet'. Then
                look in the 'Rds On' column for ones that have their on-resistance
                specified at 4.5V. They are not going to work as well at 3.3V as they
                will at 5V, but they are usable, if you keep their power dissipation
                within limits.

                Note that for p-fets, you may need to add an n-fet with a pullup to
                control them, because otherwise you won't be able to get their gate up
                to the positive rail to turn them off.

                Tony

                yellowlaser wrote:
                >
                >
                > Update:
                >
                > I managed to get something working last night. Turns out I had three
                > cascading problems that prevented the transistor/FET method from working.
                >
                > I controlled a 2n2222 transistor from the micro. The 2n2222 switched
                > the raw system voltage (~9 volts) used to control the gate of the FET.
                > This was enough voltage to turn on the FET. Works well at 20KHz.
                >
                > I still do not like the solution due to the extra parts and would
                > still love a suggestion for a good part.
                >
                > -Skye Sweeney
                >
                > --- In SeattleRobotics@yahoogroups.com
                > <mailto:SeattleRobotics%40yahoogroups.com>, FLL-Freak <fll-freak@...>
                > wrote:
                > >
                > >
                > >
                > > I am interested in controlling a 5 volt 1 amp  DC brushed motor
                > using 3.3V logic. I would like speed control via PWM but do not need
                > to reverse direction. I am thinking a full h-bridge is an overkill. A
                > simple FET/switch/ 'thing' must exist to do this!
                > >
                > >
                > >
                > > I have been playing with varius MOSFETS and found that they need
                > more than the 3.3 volts I have from the micro to turn them on. I have
                > a tube of IRLD024 logic level FETS, but they are 5 volt logic not 3.3.
                > I can't seem to find a similar part for 3.3 volt logic.
                > >
                > >
                > >
                > > I tried using an NPN transister to switch a higher control voltage
                > to the FET, but for whatever reason that does not seem to work. It
                > also increases the part count considerably.
                > >
                > >
                > >
                > > I have tried some Avago solid state relays such as the ASSR-1511 but
                > found the switching speed is very limited (about 2K Hz). I would at
                > least like to modulate the motor outside of hearing range (> 18KHz).
                > >
                > >
                > >
                > > I have done a fair amount of poking around, but can't find the right
                > key words to find a suitable part. Any suggestions would be most welcome.
                > >
                > >
                > > -Skye Sweeney
                > >
                >
                >
              • Jon Hylands
                On Thu, 01 Oct 2009 12:34:17 -0000, yellowlaser ... This is what I m using in my current robot, which is running at 3.3 volts, with one set of motors at 3.3
                Message 7 of 13 , Oct 2, 2009
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                  On Thu, 01 Oct 2009 12:34:17 -0000, "yellowlaser"
                  <fll-freak@...> wrote:

                  >I still do not like the solution due to the extra parts and would still love a suggestion for a good part.

                  This is what I'm using in my current robot, which is running at 3.3
                  volts, with one set of motors at 3.3 volts, and the other at 7.4
                  volts.

                  http://www.pololu.com/catalog/product/399

                  One chip, nothing external required. One of the really neat things
                  about this chip (that I've never seen in another hbridge) is that the
                  motor voltage can actually be lower than the digital logic voltage. So
                  you could control a 1.2 volt motor with 3.3 or 5 volt logic.

                  Later,
                  Jon
                • Jon Hylands
                  ... Sorry, the low motor voltage is 1.8 volts... Later, Jon
                  Message 8 of 13 , Oct 2, 2009
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                    On Fri, 02 Oct 2009 07:59:16 -0400, Jon Hylands <jon@...> wrote:

                    >So you could control a 1.2 volt motor with 3.3 or 5 volt logic.

                    Sorry, the low motor voltage is 1.8 volts...

                    Later,
                    Jon
                  • ranichandra72
                    add a resistor in series
                    Message 9 of 13 , Oct 2, 2009
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                      add a resistor in series
                    • Jon Hylands
                      On Fri, 02 Oct 2009 13:02:49 -0000, ranichandra72 ... Where? Why? Later, Jon
                      Message 10 of 13 , Oct 2, 2009
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                        On Fri, 02 Oct 2009 13:02:49 -0000, "ranichandra72"
                        <ranichandra72@...> wrote:

                        >add a resistor in series

                        Where?

                        Why?

                        Later,
                        Jon
                      • John Palmisano
                        ... lol I find it a common misperception on the interweb that a voltage divider is a good idea for limiting motor voltage. I think thats what he was referring
                        Message 11 of 13 , Oct 2, 2009
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                          > On Fri, 02 Oct 2009 13:02:49 -0000, "ranichandra72"
                          > <ranichandra72@...> wrote:
                          >
                          > >add a resistor in series
                          >
                          > Where?
                          >
                          > Why?
                          >
                          > Later,
                          > Jon

                          lol

                          I find it a common misperception on the interweb that a voltage
                          divider is a good idea for limiting motor voltage. I think thats what
                          he was referring to.

                          John
                          societyofrobots.com
                        • yellowlaser
                          Thank you all for your suggestions. I will take a moment to summarize as I think this is good stuff. 74ACT244 as a buffer from 3.3V logic to a 5v logic level
                          Message 12 of 13 , Oct 2, 2009
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                            Thank you all for your suggestions. I will take a moment to summarize as I think this is good stuff.

                            74ACT244 as a buffer from 3.3V logic to a 5v logic level FET. Nice idea if I had more than one signal to convert. Will need to remember this trick for other signal level changing issues.

                            Pololu products. Nice stuff. The TB6612FNG with break out board is very nice. The chip is too small for me to work with directly and the board is a bit of a nuisance for this project, but for other projects this is very cool.

                            NDS8434/FDN337N. This is what I had in mind. The only problem is working with SO-8 SOT-23 sized parts. If they only had it in a standard transitor package! But the FDN337N with only 3 leads is just barely doable.

                            LB1836M. A nice part but the tiny package is very hard to work with.

                            TLE5206. A bit of an overkill as it is a full bridge but the TO220 type part is easy to work with.

                            Si9986. A bit of an overkill as it is a full bridge.

                            At this point I will likely order a few FDN337N and solder pigtails to them using the microscope I have at work. When I am done prototyping, I can have a circuit board made for the part.

                            Thanks for all the ideas.

                            -Skye Sweeney
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