On 5/16/2017 1:59 PM, Tim Wescott wrote:> On Tue, 16 May 2017 09:22:59 -0700, mrdarrett wrote: > >> >> You might have to write another book! I took a peek at your Controls >> book and I had no idea Scilab was free. A free Matlab clone, huh? >> >> Michael > > BETTER than Matlab. For a certain meaning of "better" (it's not > compatible), but I like it. > > People keep trying to tell me to use Python for scientific computation, > and I keep stabbing at learning it, only to gag at learning yet another > interpreted language (and, I'm sorry, indentation should NOT tell the > compiler what the program structure is -- that's simply nuts).I know a variation of Forth that uses color for syntax. There are modes of execution of the code. Some code is executed by the editor, some by the compiler and some is run time. They are all distinguished by color (along with some other categories like comments). Oddly enough it is called... ColorForth (written with "color" in red and "Forth" in green). -- Rick C
mosfet driver needed for logic-level mosfets?
Started by ●May 15, 2017
Reply by ●May 17, 20172017-05-17
Reply by ●May 17, 20172017-05-17
On Wed, 17 May 2017 13:53:05 -0400, rickman wrote:> On 5/16/2017 1:59 PM, Tim Wescott wrote: >> On Tue, 16 May 2017 09:22:59 -0700, mrdarrett wrote: >> >> >>> You might have to write another book! I took a peek at your Controls >>> book and I had no idea Scilab was free. A free Matlab clone, huh? >>> >>> Michael >> >> BETTER than Matlab. For a certain meaning of "better" (it's not >> compatible), but I like it. >> >> People keep trying to tell me to use Python for scientific computation, >> and I keep stabbing at learning it, only to gag at learning yet another >> interpreted language (and, I'm sorry, indentation should NOT tell the >> compiler what the program structure is -- that's simply nuts). > > I know a variation of Forth that uses color for syntax. There are modes > of execution of the code. Some code is executed by the editor, some by > the compiler and some is run time. They are all distinguished by color > (along with some other categories like comments). > > Oddly enough it is called... ColorForth (written with "color" in red > and "Forth" in green).Eeew. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Reply by ●May 17, 20172017-05-17
On Wed, 17 May 2017 09:40:57 -0700 (PDT), mrdarrett@gmail.com wrote:>On Tuesday, May 16, 2017 at 8:30:26 PM UTC-7, John Larkin wrote: >> On Tue, 16 May 2017 12:42:58 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> >On Monday, May 15, 2017 at 10:37:52 AM UTC-7, Tim Wescott wrote: >> >> On Mon, 15 May 2017 08:33:58 -0700, mrdarrett wrote: >> >> >> >> > Hello, >> >> > >> >> > I've discovered logic-level mosfets, and am using an Arduino to drive a >> >> > small 12VDC (about an amp or so) pump motor with PWM, using an IRLZ34N >> >> > as the power mosfet. >> >> > >> >> > Would a mosfet-driver be recommended to switch that mosfet on and off >> >> > more quickly? Or is a logic-level mosfet already designed to >> >> > efficiently turn on and off with the weak logic level signal? >> >> >> >> Given that you are also asking about BJT vs. FET, note that in order to >> >> switch at it's fastest, a BJT needs a base driver that can push charge in >> >> quickly and actively pull it out quickly. The difference in recovery >> >> from saturation when you pull the base below ground vs. when you just >> >> pull it _to_ ground can be dramatic. >> >> >> >> And don't use a grotty old TIP31 if you want speed -- Zetex developed >> >> some pretty impressive modern BJTs before they got bought by Diodes, >> >> Inc., and turned into a cash cow. Those transistors are still sold, and >> >> have some pretty impressive HFE_sat and VCE_sat numbers. >> >> >> >> -- >> >> >> >> Tim Wescott >> >> Wescott Design Services >> >> http://www.wescottdesign.com >> >> >> >> I'm looking for work -- see my website! >> > >> > >> >This is an interesting article. It does mention pulling the base to -1V. Is this the article you were referring to? >> > >> >https://www.diodes.com/assets/App-Note-Files/zetex/an14.pdf >> > >> >Also noteworthy: >> > >> >"This isn't to exclude MOSFET based designs (some IC vendors have specified MOS as this suits their technology) but in terms of equivalent on-resistance and silicon efficiency, the low voltage bipolar device has no equal. For example, the ZETEX ZTX849 E-Line (TO-92 compatible) transistor exhibits a RCE(sat) of 36m?. This can only be matched by a much larger (and expensive) MOSFET die, only >> >available in TO-220, D-Pak, and similar larger packages." >> > >> >Michael >> >> That's kinda old. Actually, very old. There are some milliohm mosfets >> around now. >> >> https://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AO3416/785-1011-2-ND/1855783 >> >> >> >> -- >> >> John Larkin Highland Technology, Inc >> >> lunatic fringe electronics > > >Oh nice! > >From the datasheet, Vgs,th,max = 1.1V. This should work fine as a logic-level mosfet, then? > >http://aosmd.com/res/data_sheets/AO3416.pdfIf you have 2.5V of gate drive, that makes <26 mohms ON resistance. 3.3 volts, even lower. If there is a possibility that your drive port could go hi-Z (like maybe a uP port that's not configured at powerup) a resistor from gate to ground, 10K or something, would be prudent.> >In general, for PWM at 1-2A, 12-18VDC, are mosfets preferred (lower resistance, cheaper) than BJTs? > >Thanks, > >MichaelI sure prefer them. I rarely use bipolar transistors these days. Maybe exotica like emitter followers or cascodes or something. Bipolars do have lower capacitances, which sometimes matters. But for power switching, mosfets are great. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●May 17, 20172017-05-17
On Wednesday, May 17, 2017 at 11:33:56 AM UTC-7, Tim Wescott wrote:> On Wed, 17 May 2017 13:53:05 -0400, rickman wrote: > > > On 5/16/2017 1:59 PM, Tim Wescott wrote: > >> On Tue, 16 May 2017 09:22:59 -0700, mrdarrett wrote: > >> > >> > >>> You might have to write another book! I took a peek at your Controls > >>> book and I had no idea Scilab was free. A free Matlab clone, huh? > >>> > >>> Michael > >> > >> BETTER than Matlab. For a certain meaning of "better" (it's not > >> compatible), but I like it. > >> > >> People keep trying to tell me to use Python for scientific computation, > >> and I keep stabbing at learning it, only to gag at learning yet another > >> interpreted language (and, I'm sorry, indentation should NOT tell the > >> compiler what the program structure is -- that's simply nuts). > > > > I know a variation of Forth that uses color for syntax. There are modes > > of execution of the code. Some code is executed by the editor, some by > > the compiler and some is run time. They are all distinguished by color > > (along with some other categories like comments). > > > > Oddly enough it is called... ColorForth (written with "color" in red > > and "Forth" in green). > > Eeew. > > -- > > Tim Wescott > Wescott Design Services > http://www.wescottdesign.comIt would be a nightmare for those of us who are moderately color blind :) I can barely tell the yeasts apart on page 12. http://www.fermentis.com/brewing/craftbrewing/tips-tricks/ Michael
Reply by ●May 17, 20172017-05-17
On Wednesday, May 17, 2017 at 11:37:22 AM UTC-7, John Larkin wrote: *squish*> >> That's kinda old. Actually, very old. There are some milliohm mosfets > >> around now. > >> > >> https://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AO3416/785-1011-2-ND/1855783 > >> > >> > >> > >> -- > >> > >> John Larkin Highland Technology, Inc > >> > >> lunatic fringe electronics > > > > > >Oh nice! > > > >From the datasheet, Vgs,th,max = 1.1V. This should work fine as a logic-level mosfet, then? > > > >http://aosmd.com/res/data_sheets/AO3416.pdf > > If you have 2.5V of gate drive, that makes <26 mohms ON resistance. > 3.3 volts, even lower. > > If there is a possibility that your drive port could go hi-Z (like > maybe a uP port that's not configured at powerup) a resistor from gate > to ground, 10K or something, would be prudent. > > > > >In general, for PWM at 1-2A, 12-18VDC, are mosfets preferred (lower resistance, cheaper) than BJTs? > > > >Thanks, > > > >Michael > > I sure prefer them. I rarely use bipolar transistors these days. Maybe > exotica like emitter followers or cascodes or something. Bipolars do > have lower capacitances, which sometimes matters. But for power > switching, mosfets are great. > > > -- > > John Larkin Highland Technology, Inc > picosecond timing precision measurement > > jlarkin att highlandtechnology dott com > http://www.highlandtechnology.comCool! Thanks! Michael
Reply by ●May 17, 20172017-05-17
On Wed, 17 May 2017 11:41:42 -0700 (PDT), mrdarrett@gmail.com wrote:>On Wednesday, May 17, 2017 at 11:33:56 AM UTC-7, Tim Wescott wrote: >> On Wed, 17 May 2017 13:53:05 -0400, rickman wrote: >> >> > On 5/16/2017 1:59 PM, Tim Wescott wrote: >> >> On Tue, 16 May 2017 09:22:59 -0700, mrdarrett wrote: >> >> >> >> >> >>> You might have to write another book! I took a peek at your Controls >> >>> book and I had no idea Scilab was free. A free Matlab clone, huh? >> >>> >> >>> Michael >> >> >> >> BETTER than Matlab. For a certain meaning of "better" (it's not >> >> compatible), but I like it. >> >> >> >> People keep trying to tell me to use Python for scientific computation, >> >> and I keep stabbing at learning it, only to gag at learning yet another >> >> interpreted language (and, I'm sorry, indentation should NOT tell the >> >> compiler what the program structure is -- that's simply nuts). >> > >> > I know a variation of Forth that uses color for syntax. There are modes >> > of execution of the code. Some code is executed by the editor, some by >> > the compiler and some is run time. They are all distinguished by color >> > (along with some other categories like comments). >> > >> > Oddly enough it is called... ColorForth (written with "color" in red >> > and "Forth" in green). >> >> Eeew. >> >> -- >> >> Tim Wescott >> Wescott Design Services >> http://www.wescottdesign.com > > >It would be a nightmare for those of us who are moderately color blind :)Forth is a nightmare no matter what your vision.> >I can barely tell the yeasts apart on page 12. >http://www.fermentis.com/brewing/craftbrewing/tips-tricks/ > >Michael-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●May 17, 20172017-05-17
On 5/17/2017 2:41 PM, mrdarrett@gmail.com wrote:> On Wednesday, May 17, 2017 at 11:33:56 AM UTC-7, Tim Wescott wrote: >> On Wed, 17 May 2017 13:53:05 -0400, rickman wrote: >> >>> On 5/16/2017 1:59 PM, Tim Wescott wrote: >>>> On Tue, 16 May 2017 09:22:59 -0700, mrdarrett wrote: >>>> >>>> >>>>> You might have to write another book! I took a peek at your Controls >>>>> book and I had no idea Scilab was free. A free Matlab clone, huh? >>>>> >>>>> Michael >>>> >>>> BETTER than Matlab. For a certain meaning of "better" (it's not >>>> compatible), but I like it. >>>> >>>> People keep trying to tell me to use Python for scientific computation, >>>> and I keep stabbing at learning it, only to gag at learning yet another >>>> interpreted language (and, I'm sorry, indentation should NOT tell the >>>> compiler what the program structure is -- that's simply nuts). >>> >>> I know a variation of Forth that uses color for syntax. There are modes >>> of execution of the code. Some code is executed by the editor, some by >>> the compiler and some is run time. They are all distinguished by color >>> (along with some other categories like comments). >>> >>> Oddly enough it is called... ColorForth (written with "color" in red >>> and "Forth" in green). >> >> Eeew. >> >> -- >> >> Tim Wescott >> Wescott Design Services >> http://www.wescottdesign.com > > > It would be a nightmare for those of us who are moderately color blind :)Yeah, there's supposed to be some way of getting around that, but I don't recall. It was written by one person for himself, Chuck Moore. -- Rick C
Reply by ●May 17, 20172017-05-17
On 5/17/2017 2:56 PM, John Larkin wrote:> On Wed, 17 May 2017 11:41:42 -0700 (PDT), mrdarrett@gmail.com wrote: > >> On Wednesday, May 17, 2017 at 11:33:56 AM UTC-7, Tim Wescott wrote: >>> On Wed, 17 May 2017 13:53:05 -0400, rickman wrote: >>> >>>> On 5/16/2017 1:59 PM, Tim Wescott wrote: >>>>> On Tue, 16 May 2017 09:22:59 -0700, mrdarrett wrote: >>>>> >>>>> >>>>>> You might have to write another book! I took a peek at your Controls >>>>>> book and I had no idea Scilab was free. A free Matlab clone, huh? >>>>>> >>>>>> Michael >>>>> >>>>> BETTER than Matlab. For a certain meaning of "better" (it's not >>>>> compatible), but I like it. >>>>> >>>>> People keep trying to tell me to use Python for scientific computation, >>>>> and I keep stabbing at learning it, only to gag at learning yet another >>>>> interpreted language (and, I'm sorry, indentation should NOT tell the >>>>> compiler what the program structure is -- that's simply nuts). >>>> >>>> I know a variation of Forth that uses color for syntax. There are modes >>>> of execution of the code. Some code is executed by the editor, some by >>>> the compiler and some is run time. They are all distinguished by color >>>> (along with some other categories like comments). >>>> >>>> Oddly enough it is called... ColorForth (written with "color" in red >>>> and "Forth" in green). >>> >>> Eeew. >>> >>> -- >>> >>> Tim Wescott >>> Wescott Design Services >>> http://www.wescottdesign.com >> >> >> It would be a nightmare for those of us who are moderately color blind :) > > Forth is a nightmare no matter what your vision.From someone who doesn't program. Forth is easy to learn, but you have to learn it. Funny though. Programming in Forth requires you to start with the basics (it doesn't have arrays built in for example, but they are easy to create, very easy) but can be very powerful opening the full potential of the system you are running on. That strikes me as analogous to the way JL does analog. I guess when it comes to things he doesn't understand he expects it all to have been done for him. -- Rick C
Reply by ●May 18, 20172017-05-18
On 2017-05-16, Tim Wescott <seemywebsite@myfooter.really> wrote:> On Tue, 16 May 2017 05:01:34 -0400, default wrote: > >> On Mon, 15 May 2017 12:02:39 -0700 (PDT), mrdarrett@gmail.com wrote: >> >> https://en.wikipedia.org/wiki/Baker_clamp > > That's not at all what I was referring to. Zetex (or somebody) figured > out that you could go ahead and let the transistor saturate, but still > get significantly faster turn-off if you actively drew the carriers out > of the base.maybe just stick the right capacitor in parallel with the base or with most of the base resistance. -- This email has not been checked by half-arsed antivirus software
Reply by ●May 18, 20172017-05-18
On 5/15/2017 10:33 AM, mrdarrett@gmail.com wrote:> Hello, > > I've discovered logic-level mosfets, and am using an Arduino to drive a small 12VDC (about an amp or so) pump motor with PWM, using an IRLZ34N as the power mosfet. > > Would a mosfet-driver be recommended to switch that mosfet on and off more quickly? Or is a logic-level mosfet already designed to efficiently turn on and off with the weak logic level signal? > > Thanks, > > Michael >This doesn't sound like a very critical application. So it might be overkill, have you looked at the TC4420 series of FET drivers.> http://www.learn-c.com/tc4429.pdfMikek
