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5v buck converter?

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  • Chris Kantarjiev
    I m interested in packing a 5V buck converter into a DE-9 shell, to take 12V in and provide power to the attached GPS - typically 60-80mA, but it would be nice
    Message 1 of 18 , Sep 1, 2009
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      I'm interested in packing a 5V buck converter into a DE-9 shell, to take 12V in and provide power to
      the attached GPS - typically 60-80mA, but it would be nice to handle the Nuvi's load of 400mA.

      Can anyone suggest a simple design or readily available unit?

      Thanks!

      73 de chris K6DBG
    • Wes Johnston, AI4PX
      I d be interested in something like that potted in epoxy for my motorcycle to run the nuvi. Anyone know of anything off the shelf? Wes ... -- Wes ... We are
      Message 2 of 18 , Sep 1, 2009
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        I'd be interested in something like that potted in epoxy for my motorcycle to run the nuvi.  Anyone know of anything off the shelf?
        Wes

        On Tue, Sep 1, 2009 at 15:04, Chris Kantarjiev <cak@...> wrote:
        I'm interested in packing a 5V buck converter into a DE-9 shell, to take 12V in and provide power to
        the attached GPS - typically 60-80mA, but it would be nice to handle the Nuvi's load of 400mA.

        Can anyone suggest a simple design or readily available unit?

        Thanks!

        73 de chris K6DBG


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        --
        Wes
        ---
        We are learning a lot more about Chicago-style politics than I ever wanted.
      • Jason KG4WSV
        ... Disembowel a (preferably cheap) cig lighter power adapter. A USB model will be 5V. It may or may not fit inside a DB9 shell, though. -Jason kg4wsv
        Message 3 of 18 , Sep 1, 2009
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          On Tue, Sep 1, 2009 at 2:04 PM, Chris Kantarjiev<cak@...> wrote:
          >
          > Can anyone suggest a simple design or readily available unit?

          Disembowel a (preferably cheap) cig lighter power adapter. A USB
          model will be 5V.

          It may or may not fit inside a DB9 shell, though.

          -Jason
          kg4wsv
        • Paul Vittorino
          Wes, Take a look at Paul
          Message 4 of 18 , Sep 1, 2009
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            Wes,

            Take a look at <http://www.gilsson.com/garmin_gps/cables/GUSB5V-B.htm>

            Paul

            On Tue, Sep 1, 2009 at 2:11 PM, Wes Johnston, AI4PX<wes@...> wrote:
            >
            >
            > I'd be interested in something like that potted in epoxy for my motorcycle
            > to run the nuvi.  Anyone know of anything off the shelf?
            > Wes
            >
            > On Tue, Sep 1, 2009 at 15:04, Chris Kantarjiev <cak@...> wrote:
            >>
            >> I'm interested in packing a 5V buck converter into a DE-9 shell, to take
            >> 12V in and provide power to
            >> the attached GPS - typically 60-80mA, but it would be nice to handle the
            >> Nuvi's load of 400mA.
            >>
            >> Can anyone suggest a simple design or readily available unit?
            >>
            >> Thanks!
            >>
            >> 73 de chris K6DBG
            >>
            >>
            >> ------------------------------------
            >>
            >> Yahoo! Groups Links
            >>
            >>
            >>
            >
            >
            >
            > --
            > Wes
            > ---
            > We are learning a lot more about Chicago-style politics than I ever wanted.
            >
          • gsdatplace
            ... Simplest and cheapest I ve found (and I bought everyone I could) Duracell makes a beautifully tiny cigarette lighter to USB charger adapter. 12V in, 5Vdc
            Message 5 of 18 , Sep 1, 2009
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              --- In tracker2@yahoogroups.com, Chris Kantarjiev <cak@...> wrote:
              >
              > I'm interested in packing a 5V buck converter into a DE-9 shell, to take 12V in and provide power to
              > the attached GPS - typically 60-80mA, but it would be nice to handle the Nuvi's load of 400mA.
              >
              > Can anyone suggest a simple design or readily available unit?
              >
              > Thanks!
              >
              > 73 de chris K6DBG
              >

              Simplest and cheapest I've found (and I bought everyone I could) Duracell makes a beautifully tiny cigarette lighter to USB charger adapter. 12V in, 5Vdc at up to 1A out. I've taken a couple apart now, one is mounted inside my OT2 (like I said very small switching supply) off the power control output which powers up and down my nuvi based on profile switching or remote commands. Picked them up for $6.99, I'm sure it must have been a pricing mistake (in my favour)
              Belkin makes a tiny one as well.
              http://www.reghardware.co.uk/2009/04/24/duracell_belkin_usb/

              Garrett
              VE6RKY
            • Erich J. Ritzmann
              For 5vdc 1 amp, I am using a 7805 with a couple of caps -- 0.33 uF between the the input and ground, a 0.1 uF between the output and ground -- tied together on
              Message 6 of 18 , Sep 1, 2009
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                For 5vdc 1 amp, I am using a 7805 with a couple of caps -- 0.33 uF
                between the the input and ground, a 0.1 uF between the output and
                ground -- tied together on a bit of perf board which I place inside
                the APO3 power relay box. Or, if not using an APO3 I put the circuit
                into a 35mm film container. I don't remember what the total cost was,
                but it couldn't have been a lot as I ended up a drawer full of 78XXs.

                On 1-Sep-09, at 3:30 PM, gsdatplace wrote:

                > --- In tracker2@yahoogroups.com, Chris Kantarjiev <cak@...> wrote:
                >>
                >> I'm interested in packing a 5V buck converter into a DE-9 shell, to
                >> take 12V in and provide power to
                >> the attached GPS - typically 60-80mA, but it would be nice to
                >> handle the Nuvi's load of 400mA.
                >>
                >> Can anyone suggest a simple design or readily available unit?
                >>
                >> Thanks!
                >>
                >> 73 de chris K6DBG
                >>
                >
                > Simplest and cheapest I've found (and I bought everyone I could)
                > Duracell makes a beautifully tiny cigarette lighter to USB charger
                > adapter. 12V in, 5Vdc at up to 1A out. I've taken a couple apart
                > now, one is mounted inside my OT2 (like I said very small switching
                > supply) off the power control output which powers up and down my
                > nuvi based on profile switching or remote commands. Picked them up
                > for $6.99, I'm sure it must have been a pricing mistake (in my favour)
                > Belkin makes a tiny one as well.
                > http://www.reghardware.co.uk/2009/04/24/duracell_belkin_usb/
                >
                > Garrett
                > VE6RKY

                --
                Erich J. Ritzmann/VA3XTO
              • Jason KG4WSV
                ... A 7805 is a linear regulator, not a switcher. It is noticeably less efficient than a switcher. It is the easiest regulated supply to build, though. -Jason
                Message 7 of 18 , Sep 1, 2009
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                  On Tue, Sep 1, 2009 at 7:10 PM, Erich J. Ritzmann<ejritz@...> wrote:
                  >
                  > For 5vdc 1 amp, I am using a 7805

                  A 7805 is a linear regulator, not a switcher. It is noticeably less
                  efficient than a switcher.

                  It is the easiest regulated supply to build, though.

                  -Jason
                  kg4wsv
                • Lynn W. Deffenbaugh (Mr)
                  And with 12v vehicle power, the efficiency isn t much of a concern, provided that you can dissipate the generated heat. If you re going with battery supply,
                  Message 8 of 18 , Sep 1, 2009
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                    And with 12v vehicle power, the efficiency isn't much of a concern,
                    provided that you can dissipate the generated heat. If you're going
                    with battery supply, the new switcher supplies are SO nice!

                    Lynn (D) - KJ4ERJ

                    Jason KG4WSV wrote:
                    > On Tue, Sep 1, 2009 at 7:10 PM, Erich J. Ritzmann<ejritz@...> wrote:
                    >
                    >> For 5vdc 1 amp, I am using a 7805
                    >>
                    >
                    > A 7805 is a linear regulator, not a switcher. It is noticeably less
                    > efficient than a switcher.
                    >
                    > It is the easiest regulated supply to build, though.
                    >
                    >
                  • Jason KG4WSV
                    On Tue, Sep 1, 2009 at 7:30 PM, Lynn W. Deffenbaugh ... Not exactly. I used a 7805 to drive a power hog of an old GPS in my old truck. The battery (yeah, big
                    Message 9 of 18 , Sep 1, 2009
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                      On Tue, Sep 1, 2009 at 7:30 PM, Lynn W. Deffenbaugh
                      (Mr)<ldeffenb@...> wrote:
                      > And with 12v vehicle power, the efficiency isn't much of a concern,

                      Not exactly.

                      I used a 7805 to drive a power hog of an old GPS in my old truck. The
                      battery (yeah, big honkin' full sized pickup truck battery) lasted
                      longer after I stopped operating it 24x7. I don't have data on it,
                      but someone made the convincing claim that it would shorten the
                      vehicle battery life, that clicked with the shorter-than-expected life
                      of my truck battery, and I got an APO. That was the last battery I
                      bought before I traded the vehicle.

                      The drain is related to current draw (my APO uses a little 7805, and
                      it has no noticeable effect), but I suspect a larger draw like the
                      ~400mA the original poster mentioned would result in detectable
                      shortening of the battery life.

                      -Jason
                      kg4wsv
                    • Lynn W. Deffenbaugh (Mr)
                      ... Being an APO user in my two tracked vehicles, I neglected to consider those that would let it run 24x7. Also, being a Florida resident and it being summer
                      Message 10 of 18 , Sep 1, 2009
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                        Jason KG4WSV wrote:
                        > On Tue, Sep 1, 2009 at 7:30 PM, Lynn W. Deffenbaugh
                        > (Mr)<ldeffenb@...> wrote:
                        >
                        >> And with 12v vehicle power, the efficiency isn't much of a concern,
                        >>
                        >
                        > of my truck battery, and I got an APO. That was the last battery I
                        > bought before I traded the vehicle.
                        >
                        Being an APO user in my two tracked vehicles, I neglected to consider
                        those that would let it run 24x7. Also, being a Florida resident and it
                        being summer here, no one really thinks about leaving electronics
                        running in a closed car during the day!

                        Lynn (D) - KJ4ERJ
                      • Barry L. Lankford
                        ... You may get away with this linear power supply scheme if all you re powering is a tracker and a low power hockey puck GPS, but if you try to get much more
                        Message 11 of 18 , Sep 2, 2009
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                          Erich J. Ritzmann wrote:
                          > For 5vdc 1 amp, I am using a 7805 with a couple of caps -- 0.33 uF
                          > between the the input and ground, a 0.1 uF between the output and
                          > ground -- tied together on a bit of perf board which I place inside
                          > the APO3 power relay box. Or, if not using an APO3 I put the circuit
                          > into a 35mm film container. I don't remember what the total cost was,
                          > but it couldn't have been a lot as I ended up a drawer full of 78XXs.
                          >

                          You may get away with this linear power supply scheme if all you're
                          powering is a tracker and a low power hockey puck GPS, but if you try to
                          get much more current than that, you'll probably run into heat problems.
                          You may even melt the case you put it in or more likely the regulator IC
                          will go into thermal shutdown mode.

                          You don't mention a lot of details of the components used, specifically the
                          case style of the 3-terminal regulator or whether any heatsink is used, but
                          from what you describe of housing the circuit, it doesn't sound like
                          there's much opportunity to get rid of heat. It sounds as though there's
                          little or no air circulation inside the case, and possibly no heatsink at
                          all. If you're using a version of the 78xx that has a thermal mounting
                          tab, just the tab itself isn't much of a heatsink.

                          And you'll have a lot of heat, especially if you try to run such a circuit
                          at anywhere near the 1A current you mention. You're dropping about 8.8 Vdc
                          across the regulator (13.8 - 5.0 = 8.8 Vdc). At 1A, that's 8.8 Watts, and
                          that's a lot of heat to get rid of. It's not just a matter of efficiency
                          to save the vehicle battery, it's the heat produced.

                          To try to put this amount of heat into perspective, imagine (or actually
                          try it) holding onto a 2W night light that's been on for a several minutes,
                          then imagine holding on to 4 or 5 of them.

                          Just because the 78xx device data sheet says the max output current can be
                          up to 1A, that merely means that IF ALL OTHER DESIGN REQUIREMENTS ARE MET
                          (total power dissipation, etc.) IN THE TOTAL DESIGN, then you can have up
                          to 1A on the output pin. Meeting all the other design requirements
                          frequently means you won't be able to have up to 1A output.

                          Even at the OP's desire to run 400 mA, that's 3.5+ Watts, still a lot of
                          heat (think of it as two 2W night lights). If you use a regulator that has
                          a thermal mounting tab and provide a heatsink, you'll still need to provide
                          very good ventilation to the heatsink to let the heat out.

                          There's also the issue of reliability to consider. Running an IC at very
                          high temperatures will greatly decrease the reliability of the device, and
                          I'd be concerned that a regulator failure might put the full 13.8 Vdc on
                          the GPS/Tracker. I don't recall the most common failure mode of the 78xx
                          line, but if it *CAN* fail shorted (input-to-output), you might be putting
                          a costly GPS at risk of damage.

                          Even if you design or obtain a high-efficiency SMPS that runs cool, if you
                          have a high value mapping GPS powered by it, I'd still consider adding a
                          overvoltage crowbar on the output, fuse the input and include surge
                          protection devices and polarity protection on the input to protect the
                          power supply and everything it's powering from the sometimes "undesirable
                          pecularities" of vehicle power (I used to work in an electronic engineering
                          department for a car manufacturer).

                          As for putting a switchmode power converter in a DB9, I think that'd be
                          difficult to say the least. You might be able to use one of the higher
                          switching frequency SMPS devices (>1MHz) to reduce the amount of inductance
                          required and SMT components to squeeze it inside a DB9 backshell, but it'd
                          be very close if it is doable at all, and you'd surely not have enough room
                          for any protective devices. There are some special types of DB9 backshells
                          that provide more space than the common ones you usually see, but you'd
                          still probably be better off putting it all in a separate small case wired
                          inline with the cable to the DB9

                          I've bought a few close-out Belkin cellphone mobile power adapters and the
                          ones I've got will put out about 500 mA at 5.1 Vdc. I've been able to take
                          the PC board out of the lighter plug housing and (very carefully) saw away
                          a lot of unnecessary PC board material to end up with a board not much
                          bigger than a common postage stamp. It'd easily fit in a 35mm film can,
                          and it wouldn't produce enough power loss to heat the thing up. I've put
                          mini phone jacks, mini-switches and coaxial power receptacles into DB9
                          backshells, but I still wouldn't be able to stuff one of my cut-down and
                          stripped cellphone power converters into an ordinary DB9 backshell.

                          One often useful modification I've made to the Belkin cellphone adapters is
                          to leave it in the lighter plug but replace the 2 conductor cord with a 3
                          conductor (or better still a shielded pair) cable. Run the regulated 5Vdc
                          to one of the conductors and ground to another (or the shield) and connect
                          the remaining conductor to the circuit side of the fuse in the lighter
                          plug. That gives both unregulated 13.8 Vdc and regulated 5 Vdc at the end
                          of the cable. I find that useful for some projects, and might reduce the
                          number of lighter plugs to just one.

                          I haven't looked at the power requirements of the Nuvi line, but most of
                          the larger *handheld* GPSes Garmin makes, such as the GPSMAP60/76CSx, will
                          run very well from straight 13.8 Vdc vehicle power. In fact, many of them
                          accept a wide range of input voltage, something like 8 to 36 Vdc (or
                          thereabouts). Note that those with the extended input voltage range will
                          NOT run from just 5 Vdc at the DC power receptacle.

                          Barry N4MSJ


                          > On 1-Sep-09, at 3:30 PM, gsdatplace wrote:
                          >
                          >> --- In tracker2@yahoogroups.com, Chris Kantarjiev <cak@...> wrote:
                          >>> I'm interested in packing a 5V buck converter into a DE-9 shell, to
                          >>> take 12V in and provide power to
                          >>> the attached GPS - typically 60-80mA, but it would be nice to
                          >>> handle the Nuvi's load of 400mA.
                          >>>
                          >>> Can anyone suggest a simple design or readily available unit?
                          >>>
                          >>> Thanks!
                          >>>
                          >>> 73 de chris K6DBG
                          >>>
                          >> Simplest and cheapest I've found (and I bought everyone I could)
                          >> Duracell makes a beautifully tiny cigarette lighter to USB charger
                          >> adapter. 12V in, 5Vdc at up to 1A out. I've taken a couple apart
                          >> now, one is mounted inside my OT2 (like I said very small switching
                          >> supply) off the power control output which powers up and down my
                          >> nuvi based on profile switching or remote commands. Picked them up
                          >> for $6.99, I'm sure it must have been a pricing mistake (in my favour)
                          >> Belkin makes a tiny one as well.
                          >> http://www.reghardware.co.uk/2009/04/24/duracell_belkin_usb/
                          >>
                          >> Garrett
                          >> VE6RKY
                          >
                          > --
                          > Erich J. Ritzmann/VA3XTO
                          >
                        • Erich J. Ritzmann
                          Thanks for the detailed explanation, Barry. To clarify: I use this 7805 arrangement to power the puck GPS. I left it powered for hours without heat build up,
                          Message 12 of 18 , Sep 2, 2009
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                            Thanks for the detailed explanation, Barry.

                            To clarify: I use this 7805 arrangement to power the puck GPS. I
                            left it powered for hours without heat build up, and the results were
                            good.

                            The reference to 1 amp was simply lifted from the PDF that described
                            the chip -- not the actual current draw in the mode I was using it.

                            On 2-Sep-09, at 4:54 AM, Barry L. Lankford wrote:

                            > You may get away with this linear power supply scheme if all you're
                            > powering is a tracker and a low power hockey puck GPS, but if you
                            > try to
                            > get much more current than that, you'll probably run into heat
                            > problems.

                            --
                            Erich J. Ritzmann
                          • Chris Kantarjiev
                            Thanks for all the responses. I specifically said buck converter because I ve used 7805s and know how much heat they put out. I guess I was hoping that
                            Message 13 of 18 , Sep 2, 2009
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                              Thanks for all the responses.

                              I specifically said "buck converter" because I've used 7805s and know
                              how much heat they put out. I guess I was hoping that someone would
                              point me at the details of one of the cigar lighter adapters, rather
                              than a product that I can buy and cannibalize...

                              I know that there was a little company doing these and potting them
                              in epoxy. Boost converters, too. They might have disappeared by now
                              but I'm trying to dredge them out.

                              73,
                              chris
                            • gsdatplace
                              ... Just a a point of note, (I think I remember seeing it hashed out here before sometime) if your looking to power a Nuvi from the OT2 it doesn t need a
                              Message 14 of 18 , Sep 2, 2009
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                                --- In tracker2@yahoogroups.com, "Barry L. Lankford" <BarryL@...> wrote:
                                > Even at the OP's desire to run 400 mA, that's 3.5+ Watts, still a lot of
                                > heat (think of it as two 2W night lights). If you use a regulator that has
                                > a thermal mounting tab and provide a heatsink, you'll still need to provide
                                > very good ventilation to the heatsink to let the heat out.

                                Just a a point of note, (I think I remember seeing it hashed out here before sometime) if your looking to power a Nuvi from the OT2 it doesn't need a constant 400mA to operate. For the longest time I ran my Nuvi powered directly from the OT2's internal 5V regulator with no issues. If your nuvi is totally dead, or has been off for a extended length of time it can draw up to 375-400mA when it kicks into charge mode, but even on the factory internal regulator there was no significant overheating or temperature rise that concerned me, I was also powering it via the rear port on a modified nema cable, so if the nuvi was discharged significantly the voltage drop over the wire was enough that it could take 2-3 days to fully recharge, but it operated fine the entire time. On startup it will ocassionally draw up to the 350-400mA for 5-10 seconds if the internal batter voltage has dropped a little. During normal operation the nuvi 350 only draws between 75-100mA I believe were the numbers I had when testing it.

                                Garrett
                                VE6RKY
                              • Bruce Harvey
                                Hi Chris, Have a look at this eBay item. I bought several and they seem to be similar to what you are looking for. They pop apart easily and could be
                                Message 15 of 18 , Sep 2, 2009
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                                  Hi Chris,

                                  Have a look at this eBay item.  I bought several and they seem to be similar to what you are looking for.
                                  They pop apart easily and could be incorporated into other projects. Price is decent. Shipping is "free".

                                  item #  250407945303

                                  73,
                                  Bruce, ve1ii



                                  Chris Kantarjiev wrote:
                                   

                                  Thanks for all the responses.

                                  I specifically said "buck converter" because I've used 7805s and know
                                  how much heat they put out. I guess I was hoping that someone would
                                  point me at the details of one of the cigar lighter adapters, rather
                                  than a product that I can buy and cannibalize. ..

                                  I know that there was a little company doing these and potting them
                                  in epoxy. Boost converters, too. They might have disappeared by now
                                  but I'm trying to dredge them out.

                                  73,
                                  chris


                                • Mark Cheavens
                                  What you were looking for was the post (sorry I don t have the original) about: http://www.dimensionengineering.com/DE-SWADJ.htm They also have a buck
                                  Message 16 of 18 , Sep 2, 2009
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                                    What you were looking for was the post (sorry I don't have the original) about:
                                    http://www.dimensionengineering.com/DE-SWADJ.htm

                                    They also have a buck (increase) one as well.

                                    You can also look at DigiKey for the drop in 78xx series of switchers:
                                    http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=102-1715-nd

                                    Hope that helps.

                                    Mark
                                    KC5EVE
                                    At 08:50 AM 9/2/2009, you wrote:
                                     

                                    Thanks for all the responses.

                                    I specifically said "buck converter" because I've used 7805s and know
                                    how much heat they put out. I guess I was hoping that someone would
                                    point me at the details of one of the cigar lighter adapters, rather
                                    than a product that I can buy and cannibalize...

                                    I know that there was a little company doing these and potting them
                                    in epoxy. Boost converters, too. They might have disappeared by now
                                    but I'm trying to dredge them out.

                                    73,
                                    chris
                                  • Chris Kantarjiev
                                    ... Yeah, I know. But when it does ... I m asking here because it s the hub of Nuvi activity, but I m currently looking to hook this to my D710. I am powering
                                    Message 17 of 18 , Sep 2, 2009
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                                      > if your looking to power a Nuvi from the OT2 it doesn't need a constant 4
                                      > 00mA to operate.

                                      Yeah, I know. But when it does ...

                                      I'm asking here because it's the hub of Nuvi activity, but I'm currently
                                      looking to hook this to my D710. I am powering a GPS18 by stealing
                                      from the 100mA source that's available at the microphone connector - but
                                      I don't dare hook the Nuvi to that because I don't want to
                                      pop an internal fuse or burn something out.

                                      So I'm out to find a different arrangement that I can leave in place
                                      that connects directly to 12V and provides 5V at the DE9 that goes
                                      to whatever GPS I hook up.

                                      73,
                                      chris
                                    • Joe Krout
                                      This may be what you are looking for. This is the 1 amp version, and should handle the Nuvi with no problem, http://www.dimensionengineering.com/DE-SW050.htm I
                                      Message 18 of 18 , Sep 8, 2009
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                                        This may be what you are looking for.
                                        This is the 1 amp version, and should handle the Nuvi with no problem,
                                        http://www.dimensionengineering.com/DE-SW050.htm

                                        I am using the 3 amp adjustable version, which I mounted inside the
                                        Tracker2 case. I take the 12 volts off the header rail and send the 5
                                        volts out the DB9. More power than needed, I know.

                                        Look in the files section of the group for a picture - "Switching
                                        Regulator.jpg"

                                        Joe
                                        W0PWJ

                                        On Tue, 2009-09-01 at 12:04 -0700, Chris Kantarjiev wrote:
                                        > I'm interested in packing a 5V buck converter into a DE-9 shell, to take 12V in and provide power to
                                        > the attached GPS - typically 60-80mA, but it would be nice to handle the Nuvi's load of 400mA.
                                        >
                                        > Can anyone suggest a simple design or readily available unit?
                                        >
                                        > Thanks!
                                        >
                                        > 73 de chris K6DBG
                                        >
                                        >
                                        > ------------------------------------
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                                        > Yahoo! Groups Links
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                                        >
                                        >
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