How to fix LTspice schematic
in [Design]
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From: Robert Baer on 29 Sep 2006 23:13 Johnny Boy wrote: > "Robert Baer" <robertbaer(a)earthlink.net> wrote in message > news:nb3Tg.363$Lv3.147(a)newsread1.news.pas.earthlink.net... > > <snip> > >> That might help; how does one specify Vhigh and Trise for A1? >> I was also wondering abuut a power supply for the inverter, but since >>this is an emulator, maybe one does not need to be specified? > > <snip> > > Don't know about the inverter supply, but for Vhigh/low and Trise/fall, > right-click the inverter, then copy the following into the "SpiceLine" > attribute, (edit to suit).:- > > Vhigh=12 Vlow=0 Trise=100n Tfall=100n Td=100n > > (Thanks to DNA - I found this in his alternative to your circuit.) > > When I first ran this simulation, I got the same error as you, but after > adding the above line to the inverter attributes, I get a different error:- > > Fatal Error: Singular matrix: check nodes n013 and u1:1:va+ > Iteration No. 2 > > > ... Johnny > > I got something like that also. No clues as what to fix or what changes are needed.
From: Robert Baer on 29 Sep 2006 23:21 Johnny Boy wrote: > "Robert Baer" <robertbaer(a)earthlink.net> wrote in message > news:nb3Tg.363$Lv3.147(a)newsread1.news.pas.earthlink.net... > > <snip> > >> That might help; how does one specify Vhigh and Trise for A1? >> I was also wondering abuut a power supply for the inverter, but since >>this is an emulator, maybe one does not need to be specified? > > <snip> > > Don't know about the inverter supply, but for Vhigh/low and Trise/fall, > right-click the inverter, then copy the following into the "SpiceLine" > attribute, (edit to suit).:- > > Vhigh=12 Vlow=0 Trise=100n Tfall=100n Td=100n > > (Thanks to DNA - I found this in his alternative to your circuit.) > > When I first ran this simulation, I got the same error as you, but after > adding the above line to the inverter attributes, I get a different error:- > > Fatal Error: Singular matrix: check nodes n013 and u1:1:va+ > Iteration No. 2 > > > ... Johnny > > That circuit he gave is strange: 1) "Rl" is not from output to ground, where a practical load would go. 2) R1 allows Vout to go to 1.2KV with a small ripple; without Rl, the output only goes to 500V with a lot of ripple. 3) Increasing Rf by a factor of 5 has no effect on output voltage. 4) Output voltage ramps up in a *linear* fashion. 5) Have not found what limits/controls the output voltage. 6) M1 operates in the linear mode, but "switches between two current levels. 7) Looks like the output could be in the 10KV region with minor mods (*not* changing the multiplier).
From: Johnny Boy on 30 Sep 2006 04:10 "Robert Baer" <robertbaer(a)earthlink.net> wrote in message news:fplTg.3005$Y24.2825(a)newsread4.news.pas.earthlink.net... > Johnny Boy wrote: > > > "Robert Baer" <robertbaer(a)earthlink.net> wrote in message > > news:nb3Tg.363$Lv3.147(a)newsread1.news.pas.earthlink.net... > > > > <snip> > > > >> That might help; how does one specify Vhigh and Trise for A1? > >> I was also wondering abuut a power supply for the inverter, but since > >>this is an emulator, maybe one does not need to be specified? > > > > <snip> > > > > Don't know about the inverter supply, but for Vhigh/low and Trise/fall, > > right-click the inverter, then copy the following into the "SpiceLine" > > attribute, (edit to suit).:- > > > > Vhigh=12 Vlow=0 Trise=100n Tfall=100n Td=100n > > > > (Thanks to DNA - I found this in his alternative to your circuit.) > > > > When I first ran this simulation, I got the same error as you, but after > > adding the above line to the inverter attributes, I get a different error:- > > > > Fatal Error: Singular matrix: check nodes n013 and u1:1:va+ > > Iteration No. 2 > > > > > > ... Johnny > > > > > That circuit he gave is strange: > 1) "Rl" is not from output to ground, where a practical load would go. > 2) R1 allows Vout to go to 1.2KV with a small ripple; without Rl, the > output only goes to 500V with a lot of ripple. > 3) Increasing Rf by a factor of 5 has no effect on output voltage. This surprises me - when I manually calculate feedback with the given values, the feedback voltage to the inverters is 2.5V as it should be for 1kV output. The ripple is determined by the current limit via the 100R resistor. > 4) Output voltage ramps up in a *linear* fashion. Shouldn't it do this? > 5) Have not found what limits/controls the output voltage. See my reply to >3) > 6) M1 operates in the linear mode, but "switches between two current levels. > 7) Looks like the output could be in the 10KV region with minor mods > (*not* changing the multiplier). I should point out that I'm a complete novice to LTSpice, with 2 days experience. Perhaps you should try posting this problem to the Yahoo LTSpice group. .... Johnny
From: John Smith on 30 Sep 2006 18:59 "Robert Baer" <robertbaer(a)earthlink.net> wrote in message news:DRGSg.7187$UG4.3709(a)newsread2.news.pas.earthlink.net... > I do not understand the error message and have no clue to fix it. > The inverter may be the problem; would like it to "emulate" a TPS2818 > but do not know how. > > Robert - The inverter is not your problem. Don't worry with trying to simulate a TPS2818 yet. It looks like you are trying to simulate a regulated high voltage power supply. Except for the effects of diode capacitance, the input to U2+ will remain low until D3 and D4 avalanche. Is that what you want? How much voltage across R1 do you desire? It would be much better if you posted your requrements rather than a SPICE netlist. Cheers, John
From: Robert Baer on 1 Oct 2006 06:08
Johnny Boy wrote: > "Robert Baer" <robertbaer(a)earthlink.net> wrote in message > news:fplTg.3005$Y24.2825(a)newsread4.news.pas.earthlink.net... > >>Johnny Boy wrote: >> >> >>>"Robert Baer" <robertbaer(a)earthlink.net> wrote in message >>>news:nb3Tg.363$Lv3.147(a)newsread1.news.pas.earthlink.net... >>> >>><snip> >>> >>>> That might help; how does one specify Vhigh and Trise for A1? >>>> I was also wondering abuut a power supply for the inverter, but since >>>>this is an emulator, maybe one does not need to be specified? >>> >>><snip> >>> >>>Don't know about the inverter supply, but for Vhigh/low and Trise/fall, >>>right-click the inverter, then copy the following into the "SpiceLine" >>>attribute, (edit to suit).:- >>> >>>Vhigh=12 Vlow=0 Trise=100n Tfall=100n Td=100n >>> >>>(Thanks to DNA - I found this in his alternative to your circuit.) >>> >>>When I first ran this simulation, I got the same error as you, but after >>>adding the above line to the inverter attributes, I get a different > > error:- > >>>Fatal Error: Singular matrix: check nodes n013 and u1:1:va+ >>> Iteration No. 2 >>> >>> >>>... Johnny >>> >>> >> >> That circuit he gave is strange: >>1) "Rl" is not from output to ground, where a practical load would go. >>2) R1 allows Vout to go to 1.2KV with a small ripple; without Rl, the >>output only goes to 500V with a lot of ripple. >>3) Increasing Rf by a factor of 5 has no effect on output voltage. > > > This surprises me - when I manually calculate feedback with the given > values, the feedback voltage to the inverters is 2.5V as it should be for > 1kV output. The ripple is determined by the current limit via the 100R > resistor. > > >>4) Output voltage ramps up in a *linear* fashion. > > > Shouldn't it do this? > > >>5) Have not found what limits/controls the output voltage. > > > See my reply to >3) > > >>6) M1 operates in the linear mode, but "switches between two current > > levels. > >>7) Looks like the output could be in the 10KV region with minor mods >>(*not* changing the multiplier). > > > > I should point out that I'm a complete novice to LTSpice, with 2 days > experience. > Perhaps you should try posting this problem to the Yahoo LTSpice group. > > ... Johnny > > > ....and *where* does that "2.5V" value come from????? Oh, i forgot one other strange item: the lines / wires on the diodes are *not* at right angles! How the &#$()#$ was that done??? |