IntuitSoft has a program called Spicemod (http://www.intusoft.com/spicemod.htm#Requirements) It's a "SPICE model builder" that takes data sheet parameters and makes SPICE models -- including using subcircuits, if just a .MODEL statement isn't going to be enough. I'm skeptical. Has anyone used it? Have you had good success? Do you think that models (particularly IGBT models) that come from it can be trusted? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Spicemod??
Started by ●July 6, 2011
Reply by ●July 6, 20112011-07-06
On 07/06/2011 02:48 PM, Tim Wescott wrote:> IntuitSoft has a program called Spicemod > (http://www.intusoft.com/spicemod.htm#Requirements) > > It's a "SPICE model builder" that takes data sheet parameters and makes > SPICE models -- including using subcircuits, if just a .MODEL statement > isn't going to be enough. > > I'm skeptical. > > Has anyone used it? Have you had good success? Do you think that models > (particularly IGBT models) that come from it can be trusted? >Come to think of it, can anyone recommend a good book on building SPICE models? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●July 6, 20112011-07-06
On Wed, 06 Jul 2011 14:54:44 -0700, Tim Wescott <tim@seemywebsite.com> wrote:>On 07/06/2011 02:48 PM, Tim Wescott wrote: >> IntuitSoft has a program called Spicemod >> (http://www.intusoft.com/spicemod.htm#Requirements) >> >> It's a "SPICE model builder" that takes data sheet parameters and makes >> SPICE models -- including using subcircuits, if just a .MODEL statement >> isn't going to be enough. >> >> I'm skeptical. >> >> Has anyone used it? Have you had good success? Do you think that models >> (particularly IGBT models) that come from it can be trusted? >> >Come to think of it, can anyone recommend a good book on building SPICE >models?I've never found the executables advertising themselves as model "builders" or "creators" were very adequate. In fact I've found them hilarious... take data, make a model, take data from that model, you get a different model :-( If you're trying to model semiconductors, you really need to understand the math behind the device model, because parameters tend to be interactive in unexpected ways. My son Aaron and I wrote an executable _many_ years ago (under DOS) that takes a bipolar data stream and gets all of the DC parameters. I probably should resurrect that with a GUI ;-) Though, now-a-days, MOS is king, and extraordinarily difficult to model. For chip functions behavioral modeling can be pretty good. Again it's just understanding the math that separates the men from the boys. I have several books on the subject, none of which has been terribly helpful. My most common comment is to make sure that the functions you create have no discontinuities... all derivatives exist. Thus I'm fond of fitting TANH to just about everything ;-) What are you trying to model? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●July 6, 20112011-07-06
On 07/06/2011 03:32 PM, Jim Thompson wrote:> On Wed, 06 Jul 2011 14:54:44 -0700, Tim Wescott<tim@seemywebsite.com> > wrote: > >> On 07/06/2011 02:48 PM, Tim Wescott wrote: >>> IntuitSoft has a program called Spicemod >>> (http://www.intusoft.com/spicemod.htm#Requirements) >>> >>> It's a "SPICE model builder" that takes data sheet parameters and makes >>> SPICE models -- including using subcircuits, if just a .MODEL statement >>> isn't going to be enough. >>> >>> I'm skeptical. >>> >>> Has anyone used it? Have you had good success? Do you think that models >>> (particularly IGBT models) that come from it can be trusted? >>> >> Come to think of it, can anyone recommend a good book on building SPICE >> models? > > I've never found the executables advertising themselves as model > "builders" or "creators" were very adequate. In fact I've found them > hilarious... take data, make a model, take data from that model, you > get a different model :-( > > If you're trying to model semiconductors, you really need to > understand the math behind the device model, because parameters tend > to be interactive in unexpected ways. My son Aaron and I wrote an > executable _many_ years ago (under DOS) that takes a bipolar data > stream and gets all of the DC parameters. I probably should resurrect > that with a GUI ;-) > > Though, now-a-days, MOS is king, and extraordinarily difficult to > model. > > For chip functions behavioral modeling can be pretty good. Again it's > just understanding the math that separates the men from the boys. > > I have several books on the subject, none of which has been terribly > helpful. > > My most common comment is to make sure that the functions you create > have no discontinuities... all derivatives exist. Thus I'm fond of > fitting TANH to just about everything ;-) > > What are you trying to model? > > ...Jim ThompsonIGBT, in linear mode to boot. I hear you about understanding the math -- I would hope that any book that I did get would be maybe 50% about what each parameter in each SPICE model means, with the rest devoted to helping you decide when .MODEL isn't enough and a subcircuit must be done, and examples of how to do so with various semiconductor types. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●July 6, 20112011-07-06
On Wed, 06 Jul 2011 16:08:31 -0700, Tim Wescott <tim@seemywebsite.com> wrote:>On 07/06/2011 03:32 PM, Jim Thompson wrote: >> On Wed, 06 Jul 2011 14:54:44 -0700, Tim Wescott<tim@seemywebsite.com> >> wrote: >> >>> On 07/06/2011 02:48 PM, Tim Wescott wrote: >>>> IntuitSoft has a program called Spicemod >>>> (http://www.intusoft.com/spicemod.htm#Requirements) >>>> >>>> It's a "SPICE model builder" that takes data sheet parameters and makes >>>> SPICE models -- including using subcircuits, if just a .MODEL statement >>>> isn't going to be enough. >>>> >>>> I'm skeptical. >>>> >>>> Has anyone used it? Have you had good success? Do you think that models >>>> (particularly IGBT models) that come from it can be trusted? >>>> >>> Come to think of it, can anyone recommend a good book on building SPICE >>> models? >> >> I've never found the executables advertising themselves as model >> "builders" or "creators" were very adequate. In fact I've found them >> hilarious... take data, make a model, take data from that model, you >> get a different model :-( >> >> If you're trying to model semiconductors, you really need to >> understand the math behind the device model, because parameters tend >> to be interactive in unexpected ways. My son Aaron and I wrote an >> executable _many_ years ago (under DOS) that takes a bipolar data >> stream and gets all of the DC parameters. I probably should resurrect >> that with a GUI ;-) >> >> Though, now-a-days, MOS is king, and extraordinarily difficult to >> model. >> >> For chip functions behavioral modeling can be pretty good. Again it's >> just understanding the math that separates the men from the boys. >> >> I have several books on the subject, none of which has been terribly >> helpful. >> >> My most common comment is to make sure that the functions you create >> have no discontinuities... all derivatives exist. Thus I'm fond of >> fitting TANH to just about everything ;-) >> >> What are you trying to model? >> >> ...Jim Thompson > >IGBT, in linear mode to boot. > >I hear you about understanding the math -- I would hope that any book >that I did get would be maybe 50% about what each parameter in each >SPICE model means, with the rest devoted to helping you decide when >.MODEL isn't enough and a subcircuit must be done, and examples of how >to do so with various semiconductor types.Hymowitz shows a horrendously complex behavioral model on the IntuSoft site. I'd tend toward using a 2N7000 model (Supertex appears to be best at sub-threshold) plus a PNP model, then scale each until you get a match to the data sheet. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●July 6, 20112011-07-06
On 07/06/2011 05:15 PM, Jim Thompson wrote:> On Wed, 06 Jul 2011 16:08:31 -0700, Tim Wescott<tim@seemywebsite.com> > wrote: > >> On 07/06/2011 03:32 PM, Jim Thompson wrote: >>> On Wed, 06 Jul 2011 14:54:44 -0700, Tim Wescott<tim@seemywebsite.com> >>> wrote: >>> >>>> On 07/06/2011 02:48 PM, Tim Wescott wrote: >>>>> IntuitSoft has a program called Spicemod >>>>> (http://www.intusoft.com/spicemod.htm#Requirements) >>>>> >>>>> It's a "SPICE model builder" that takes data sheet parameters and makes >>>>> SPICE models -- including using subcircuits, if just a .MODEL statement >>>>> isn't going to be enough. >>>>> >>>>> I'm skeptical. >>>>> >>>>> Has anyone used it? Have you had good success? Do you think that models >>>>> (particularly IGBT models) that come from it can be trusted? >>>>> >>>> Come to think of it, can anyone recommend a good book on building SPICE >>>> models? >>> >>> I've never found the executables advertising themselves as model >>> "builders" or "creators" were very adequate. In fact I've found them >>> hilarious... take data, make a model, take data from that model, you >>> get a different model :-( >>> >>> If you're trying to model semiconductors, you really need to >>> understand the math behind the device model, because parameters tend >>> to be interactive in unexpected ways. My son Aaron and I wrote an >>> executable _many_ years ago (under DOS) that takes a bipolar data >>> stream and gets all of the DC parameters. I probably should resurrect >>> that with a GUI ;-) >>> >>> Though, now-a-days, MOS is king, and extraordinarily difficult to >>> model. >>> >>> For chip functions behavioral modeling can be pretty good. Again it's >>> just understanding the math that separates the men from the boys. >>> >>> I have several books on the subject, none of which has been terribly >>> helpful. >>> >>> My most common comment is to make sure that the functions you create >>> have no discontinuities... all derivatives exist. Thus I'm fond of >>> fitting TANH to just about everything ;-) >>> >>> What are you trying to model? >>> >>> ...Jim Thompson >> >> IGBT, in linear mode to boot. >> >> I hear you about understanding the math -- I would hope that any book >> that I did get would be maybe 50% about what each parameter in each >> SPICE model means, with the rest devoted to helping you decide when >> .MODEL isn't enough and a subcircuit must be done, and examples of how >> to do so with various semiconductor types. > > Hymowitz shows a horrendously complex behavioral model on the IntuSoft > site. > > I'd tend toward using a 2N7000 model (Supertex appears to be best at > sub-threshold) plus a PNP model, then scale each until you get a match > to the data sheet. > > ...Jim ThompsonThe models that I have do that. Or at least they do the NMOS + PNP, with a few diodes and maybe an NPN for verisimilitude. I just don't know how much they can be trusted in linear operation, when that's not usually how IGBT's are used. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●July 6, 20112011-07-06
On Wed, 06 Jul 2011 16:08:31 -0700, Tim Wescott <tim@seemywebsite.com> wrote:>On 07/06/2011 03:32 PM, Jim Thompson wrote:[snip]>> >> What are you trying to model? >> >> ...Jim Thompson > >IGBT, in linear mode to boot. >[snip] Suddenly struck me, WHY do want an IGBT in linear mode? What characteristics are you trying to emulate? You might be better off with an MOS/Bipolar combination. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●July 6, 20112011-07-06
On 07/06/2011 05:28 PM, Jim Thompson wrote:> On Wed, 06 Jul 2011 16:08:31 -0700, Tim Wescott<tim@seemywebsite.com> > wrote: > >> On 07/06/2011 03:32 PM, Jim Thompson wrote: > [snip] >>> >>> What are you trying to model? >>> >>> ...Jim Thompson >> >> IGBT, in linear mode to boot. >> > [snip] > > Suddenly struck me, WHY do want an IGBT in linear mode?Because that's what the customer is insisting on.> What characteristics are you trying to emulate?A single honking-big device (we weren't able to find Really Big MOSFETs, and would have to use _lots_ in parallel).> You might be better off with an MOS/Bipolar combination.Strange, that's what I told my customer! They _do_ have a record of success with an IGBT in the circuit -- I'm just helping them drive it better -- so it's hard to argue against it. If I could find a bipolar transistor in a single honking-big module that may fly with them. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by ●July 6, 20112011-07-06
On Wed, 06 Jul 2011 17:40:31 -0700, Tim Wescott <tim@seemywebsite.com> wrote:>On 07/06/2011 05:28 PM, Jim Thompson wrote: >> On Wed, 06 Jul 2011 16:08:31 -0700, Tim Wescott<tim@seemywebsite.com> >> wrote: >> >>> On 07/06/2011 03:32 PM, Jim Thompson wrote: >> [snip] >>>> >>>> What are you trying to model? >>>> >>>> ...Jim Thompson >>> >>> IGBT, in linear mode to boot. >>> >> [snip] >> >> Suddenly struck me, WHY do want an IGBT in linear mode? > >Because that's what the customer is insisting on. > >> What characteristics are you trying to emulate? > >A single honking-big device (we weren't able to find Really Big MOSFETs, >and would have to use _lots_ in parallel). > >> You might be better off with an MOS/Bipolar combination. > >Strange, that's what I told my customer! > >They _do_ have a record of success with an IGBT in the circuit -- I'm >just helping them drive it better -- so it's hard to argue against it. > >If I could find a bipolar transistor in a single honking-big module that >may fly with them.Voltage rating? Current rating? Required saturation voltage? Is load inductive? IGBT's are inherently snap action devices. How do you propose keeping them from "snapping" ?? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●July 6, 20112011-07-06
On 07/06/2011 05:49 PM, Jim Thompson wrote:> On Wed, 06 Jul 2011 17:40:31 -0700, Tim Wescott<tim@seemywebsite.com> > wrote: > >> On 07/06/2011 05:28 PM, Jim Thompson wrote: >>> On Wed, 06 Jul 2011 16:08:31 -0700, Tim Wescott<tim@seemywebsite.com> >>> wrote: >>> >>>> On 07/06/2011 03:32 PM, Jim Thompson wrote: >>> [snip] >>>>> >>>>> What are you trying to model? >>>>> >>>>> ...Jim Thompson >>>> >>>> IGBT, in linear mode to boot. >>>> >>> [snip] >>> >>> Suddenly struck me, WHY do want an IGBT in linear mode? >> >> Because that's what the customer is insisting on. >> >>> What characteristics are you trying to emulate? >> >> A single honking-big device (we weren't able to find Really Big MOSFETs, >> and would have to use _lots_ in parallel). >> >>> You might be better off with an MOS/Bipolar combination. >> >> Strange, that's what I told my customer! >> >> They _do_ have a record of success with an IGBT in the circuit -- I'm >> just helping them drive it better -- so it's hard to argue against it. >> >> If I could find a bipolar transistor in a single honking-big module that >> may fly with them. > > Voltage rating?'bout 100V> Current rating?'bout 400A> Required saturation voltage?Not very important -- several volts would do OK. Keep in mind that it's used as a linear pass element for the most part.> Is load inductive?Resistive> IGBT's are inherently snap action devices. How do > you propose keeping them from "snapping" ??Well, it's that last that is exactly what worries me, it is why I tried to talk the customer into MOSFETs, and it is why I'd be interested in some other alternative. My original proposal to keep them from "snapping" was to keep them out of the circuit entirely -- that didn't work. I do know, however, that they've had these devices in-circuit in a previous product and are happy with it, so it's hard to budge them. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html
