John Larkin <jjlarkin@highlandtechnology.com> wrote:
> On Wed, 3 May 2017 14:14:35 -0000 (UTC), Don Kuenz <g@crcomp.net>
> wrote:
>>Helmut Sennewald, the LTSpice yahoo group guru, recently posted:
>>
>>-----------------------------------------------------------------------
-
>>The UniversalOpamps2 from LTspice cannot be used for high current
>>applications without a modification. I have reduced Ron in its
>>switch-model from 10Ohm to 1Ohm.
>>Right-mouse-click on the placed symbol to lower "Switch_Ron" to get
even
>>more current.
> The current model doesn't include a visible Switch_Ron parameter. I
> added one and it didn't complain, but it seemed to have no effect.
On Mon, 01 May 2017 18:12:28 -0700, John Larkin
<jjlarkin@highland_snip_technology.com> wrote:
>
>
>
>I was wondering about the power dissipation of an opamp, driving a
>sine wave into a mainly inductive load. See below.
>
>The first few cycles current limit or something. I'm using
>UniversalOpamp2 with current limit 2 amps and rail=0.
>
>This opamp isn't documented in the HELP, or much anywhere else.
>
>Peak current is under 700 mA, so why is it clipping?
>
>Higher supply voltage helps.
>
>
[snip]
Try "Op-Amp-Config.zip" on the Device Models & Subcircuits Page of my
website... _everything_ specifiable _except_ current limit.
More highly refined models available for a fee >:-}
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Thinking outside the box... producing elegant solutions.
"It is not in doing what you like, but in liking what you do that
is the secret of happiness." -James Barrie
Reply by Don Kuenz●May 3, 20172017-05-03
John Larkin <jjlarkin@highlandtechnology.com> wrote:
> On Wed, 3 May 2017 14:14:35 -0000 (UTC), Don Kuenz <g@crcomp.net>
> wrote:
>
>>
>>Winfield Hill <hill@rowland.harvard.edu> wrote:
>>> John Larkin wrote...
>>>> Winfield Hill wrote:
>>>>> John Larkin wrote...
>>>>>>
>>>>>> I'm actually using a TCA0372, which is a dual 1-amp part.
>>>>> [ snip ]
>>>>>
>>>>>> The cartoon schematic in the data sheet doesn't show any
>>>>>> current limiting!
>>>>>
>>>>> The schematic is impossible (PNP in upper output pair),
>>>>> not fixed in dozens of revs, and still there in r11.
>>>>> Candidate for Bad Circuits.
>>>>
>>>> But it is a great amp, and dirt cheap. I've used 3300
>>>> so far, no problems.
>>>
>>> John, I like to roll my own simple opamps in SPICE,
>>> for custom fT and slew rate. Ignore other niceties:
>>> multiple poles, time delays, supply-rail saturation.
>>>
>>> Use controlled-source elements: a G element provides
>>> the gain-node error current, a cap to ground sets fT.
>>> Add an E element with G=1 for the output, finish with
>>> a series output resistor for open-loop Zout. If you
>>> want current limiting, add an output sense resistor
>>> and npn + pnp current-limit BJTs with their collectors
>>> back to the gain-node.
>>>
>>> If you must have supply-rail limiting, add two diodes
>>> from gain-node to appropriately-set voltage sources.
>>> If you need better, accurate slew rate, etc. etc, then
>>> go ahead and make a Boyle macromodel, see LTC's AN48.
>>>
>>>> That's what I like about electronics. We use physics,
>>>> math, control theory, simulation, data sheets, app notes,
>>>> professional advice... and you can't trust any of them.
>>>
>>> Snork!
>>>
>>
>>Helmut Sennewald, the LTSpice yahoo group guru, recently posted:
>>
>>------------------------------------------------------------------------
>>
>>The UniversalOpamps2 from LTspice cannot be used for high current
>>applications without a modification. I have reduced Ron in its
>>switch-model from 10Ohm to 1Ohm.
>>
>>Right-mouse-click on the placed symbol to lower "Switch_Ron" to get even
>>more current.
>
> The current model doesn't include a visible Switch_Ron parameter. I
> added one and it didn't complain, but it seemed to have no effect.
>
>
>>
>>You can download an example which I made 2012.
>>
>>UniversalOpamps2power_test.zip
>>https://groups.yahoo.com/neo/groups/LTspice/files/%20Lib/
>
> I'm not registered with Yahoo.
>
On Wed, 3 May 2017 14:14:35 -0000 (UTC), Don Kuenz <g@crcomp.net>
wrote:
>
>Winfield Hill <hill@rowland.harvard.edu> wrote:
>> John Larkin wrote...
>>> Winfield Hill wrote:
>>>> John Larkin wrote...
>>>>>
>>>>> I'm actually using a TCA0372, which is a dual 1-amp part.
>>>> [ snip ]
>>>>
>>>>> The cartoon schematic in the data sheet doesn't show any
>>>>> current limiting!
>>>>
>>>> The schematic is impossible (PNP in upper output pair),
>>>> not fixed in dozens of revs, and still there in r11.
>>>> Candidate for Bad Circuits.
>>>
>>> But it is a great amp, and dirt cheap. I've used 3300
>>> so far, no problems.
>>
>> John, I like to roll my own simple opamps in SPICE,
>> for custom fT and slew rate. Ignore other niceties:
>> multiple poles, time delays, supply-rail saturation.
>>
>> Use controlled-source elements: a G element provides
>> the gain-node error current, a cap to ground sets fT.
>> Add an E element with G=1 for the output, finish with
>> a series output resistor for open-loop Zout. If you
>> want current limiting, add an output sense resistor
>> and npn + pnp current-limit BJTs with their collectors
>> back to the gain-node.
>>
>> If you must have supply-rail limiting, add two diodes
>> from gain-node to appropriately-set voltage sources.
>> If you need better, accurate slew rate, etc. etc, then
>> go ahead and make a Boyle macromodel, see LTC's AN48.
>>
>>> That's what I like about electronics. We use physics,
>>> math, control theory, simulation, data sheets, app notes,
>>> professional advice... and you can't trust any of them.
>>
>> Snork!
>>
>
>Helmut Sennewald, the LTSpice yahoo group guru, recently posted:
>
>------------------------------------------------------------------------
>
>The UniversalOpamps2 from LTspice cannot be used for high current
>applications without a modification. I have reduced Ron in its
>switch-model from 10Ohm to 1Ohm.
>
>Right-mouse-click on the placed symbol to lower "Switch_Ron" to get even
>more current.
The current model doesn't include a visible Switch_Ron parameter. I
added one and it didn't complain, but it seemed to have no effect.
I'm not registered with Yahoo.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by Don Kuenz●May 3, 20172017-05-03
Winfield Hill <hill@rowland.harvard.edu> wrote:
> John Larkin wrote...
>> Winfield Hill wrote:
>>> John Larkin wrote...
>>>>
>>>> I'm actually using a TCA0372, which is a dual 1-amp part.
>>> [ snip ]
>>>
>>>> The cartoon schematic in the data sheet doesn't show any
>>>> current limiting!
>>>
>>> The schematic is impossible (PNP in upper output pair),
>>> not fixed in dozens of revs, and still there in r11.
>>> Candidate for Bad Circuits.
>>
>> But it is a great amp, and dirt cheap. I've used 3300
>> so far, no problems.
>
> John, I like to roll my own simple opamps in SPICE,
> for custom fT and slew rate. Ignore other niceties:
> multiple poles, time delays, supply-rail saturation.
>
> Use controlled-source elements: a G element provides
> the gain-node error current, a cap to ground sets fT.
> Add an E element with G=1 for the output, finish with
> a series output resistor for open-loop Zout. If you
> want current limiting, add an output sense resistor
> and npn + pnp current-limit BJTs with their collectors
> back to the gain-node.
>
> If you must have supply-rail limiting, add two diodes
> from gain-node to appropriately-set voltage sources.
> If you need better, accurate slew rate, etc. etc, then
> go ahead and make a Boyle macromodel, see LTC's AN48.
>
>> That's what I like about electronics. We use physics,
>> math, control theory, simulation, data sheets, app notes,
>> professional advice... and you can't trust any of them.
>
> Snork!
>
Helmut Sennewald, the LTSpice yahoo group guru, recently posted:
------------------------------------------------------------------------
The UniversalOpamps2 from LTspice cannot be used for high current
applications without a modification. I have reduced Ron in its
switch-model from 10Ohm to 1Ohm.
Right-mouse-click on the placed symbol to lower "Switch_Ron" to get even
more current.
You can download an example which I made 2012.
UniversalOpamps2power_test.zip
https://groups.yahoo.com/neo/groups/LTspice/files/%20Lib/
I will check later whether the UniversalOpamp2 model has changed since that time.
------------------------------------------------------------------------
In regards to electronics being an amalgamation of many things, it turns
out that my job description is gestalting generalist.
A generalist knows more and more about less and less until
until eventually he knows nothing about everything. A
specialist knows more and more about less and less until
eventually he knows everything about nothing.
###
BTW Win, TIA for the circuit boards that you are sending me.
Thank you,
--
Don Kuenz KB7RPU
Reply by John Larkin●May 3, 20172017-05-03
On 3 May 2017 04:40:33 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:
>John Larkin wrote...
>> Winfield Hill wrote:
>>> John Larkin wrote...
>>>>
>>>> I'm actually using a TCA0372, which is a dual 1-amp part.
>>> [ snip ]
>>>
>>>> The cartoon schematic in the data sheet doesn't show any
>>>> current limiting!
>>>
>>> The schematic is impossible (PNP in upper output pair),
>>> not fixed in dozens of revs, and still there in r11.
>>> Candidate for Bad Circuits.
>>
>> But it is a great amp, and dirt cheap. I've used 3300
>> so far, no problems.
>
> John, I like to roll my own simple opamps in SPICE,
> for custom fT and slew rate. Ignore other niceties:
> multiple poles, time delays, supply-rail saturation.
>
> Use controlled-source elements: a G element provides
> the gain-node error current, a cap to ground sets fT.
> Add an E element with G=1 for the output, finish with
> a series output resistor for open-loop Zout. If you
> want current limiting, add an output sense resistor
> and npn + pnp current-limit BJTs with their collectors
> back to the gain-node.
>
> If you must have supply-rail limiting, add two diodes
> from gain-node to appropriately-set voltage sources.
> If you need better, accurate slew rate, etc. etc, then
> go ahead and make a Boyle macromodel, see LTC's AN48.
>
>> That's what I like about electronics. We use physics,
>> math, control theory, simulation, data sheets, app notes,
>> professional advice... and you can't trust any of them.
>
> Snork!
I sometimes use "e" as an opamp, with or without adding a single-pole
rolloff. Doesn't need power supplies! But UniversalOpamp2 has slew
rate, e and i noise, offset, bandwidth, current limiting, rail swing
(which may be squirreley), bias currents, all that. I often use it
as-is, or maybe tweak one or two parameters. That's easier than using
an LTC part, unless you're familiar with it already.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
Reply by Winfield Hill●May 3, 20172017-05-03
John Larkin wrote...
> Winfield Hill wrote:
>> John Larkin wrote...
>>>
>>> I'm actually using a TCA0372, which is a dual 1-amp part.
>> [ snip ]
>>
>>> The cartoon schematic in the data sheet doesn't show any
>>> current limiting!
>>
>> The schematic is impossible (PNP in upper output pair),
>> not fixed in dozens of revs, and still there in r11.
>> Candidate for Bad Circuits.
>
> But it is a great amp, and dirt cheap. I've used 3300
> so far, no problems.
John, I like to roll my own simple opamps in SPICE,
for custom fT and slew rate. Ignore other niceties:
multiple poles, time delays, supply-rail saturation.
Use controlled-source elements: a G element provides
the gain-node error current, a cap to ground sets fT.
Add an E element with G=1 for the output, finish with
a series output resistor for open-loop Zout. If you
want current limiting, add an output sense resistor
and npn + pnp current-limit BJTs with their collectors
back to the gain-node.
If you must have supply-rail limiting, add two diodes
from gain-node to appropriately-set voltage sources.
If you need better, accurate slew rate, etc. etc, then
go ahead and make a Boyle macromodel, see LTC's AN48.
> That's what I like about electronics. We use physics,
> math, control theory, simulation, data sheets, app notes,
> professional advice... and you can't trust any of them.
Snork!
--
Thanks,
- Win
Reply by Jim Thompson●May 3, 20172017-05-03
On Wed, 3 May 2017 03:52:46 -0000 (UTC), Don Kuenz <g@crcomp.net>
wrote:
>
>Jim Thompson <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:
>
>> E-mail Helmut Sennewald <helmutsennewald@yahoo.com> and ask how to
>> join... I can't remember how it's done since Yahoo @#$%'d up
>> everything.
>
>Larkin's question was posted by me into the yahoo group earlier today.
>After three attempts two of my posts eventually showed up on the mail
>list. Yahoo's group web page is too FUBAR for me to see my own posts
>there. YMMV.
I gave up trying to post via the web. Fortunately you can do it
easily via E-mail reply from the Digest E-mail.
>
>Here's a copy-and-paste of the only response from the LTSpice yahoo
>group thus far:
>
>------------------------------------------------------------------------
>
>Don asked questions about the UniversalOpamp2 in LTspice.
>
>> "This opamp isn't documented in the HELP, or much anywhere else."
>
>True ... but there is a little bit to be found on the example schematic at
> ...\examples\Educational\UniversalOpamp2.asc
>where it shows the four available versions or levels.
>
>> "The first few cycles current limit or something. I'm using
>> UniversalOpamp2 with current limit 2 amps and rail=0."
>
>It does indeed. It is not related to or caused by the "ilimit=2" parameter which h
>as a hard limit at 2 amps. It seems to be going into soft limiting beginning somew
>here around 0.5 amps. It also depends on whether the load is resistive or inductiv
>e; and the limiting is not at the peak of either the voltage or the current. (It's
> almost like a slew rate limit of the output current?)
>
>I'd recommend posing this question to Mike Engelhardt himself. Send your question
>and schematic to the address shown in Help > About LTspice.
>
>------------------------------------------------------------------------
>
>As noted earlier, yahoo's group web page is FUBAR for me. So, another
>subscriber needs to obtain Engelhardt's email addy.
>
>Thank you,
Mike Engelhardt <LTspice@linear.com>
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| STV, Queen Creek, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Thinking outside the box... producing elegant solutions.
"It is not in doing what you like, but in liking what you do that
is the secret of happiness." -James Barrie
Reply by Don Kuenz●May 3, 20172017-05-03
Jim Thompson <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:
> E-mail Helmut Sennewald <helmutsennewald@yahoo.com> and ask how to
> join... I can't remember how it's done since Yahoo @#$%'d up
> everything.
Larkin's question was posted by me into the yahoo group earlier today.
After three attempts two of my posts eventually showed up on the mail
list. Yahoo's group web page is too FUBAR for me to see my own posts
there. YMMV.
Here's a copy-and-paste of the only response from the LTSpice yahoo
group thus far:
------------------------------------------------------------------------
Don asked questions about the UniversalOpamp2 in LTspice.
> "This opamp isn't documented in the HELP, or much anywhere else."
True ... but there is a little bit to be found on the example schematic at
...\examples\Educational\UniversalOpamp2.asc
where it shows the four available versions or levels.
> "The first few cycles current limit or something. I'm using
> UniversalOpamp2 with current limit 2 amps and rail=0."
It does indeed. It is not related to or caused by the "ilimit=2" parameter which h
as a hard limit at 2 amps. It seems to be going into soft limiting beginning somew
here around 0.5 amps. It also depends on whether the load is resistive or inductiv
e; and the limiting is not at the peak of either the voltage or the current. (It's
almost like a slew rate limit of the output current?)
I'd recommend posing this question to Mike Engelhardt himself. Send your question
and schematic to the address shown in Help > About LTspice.
------------------------------------------------------------------------
As noted earlier, yahoo's group web page is FUBAR for me. So, another
subscriber needs to obtain Engelhardt's email addy.
Thank you,
--
Don Kuenz KB7RPU
Reply by John Larkin●May 2, 20172017-05-02
On 2 May 2017 19:32:32 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:
>John Larkin wrote...
>>
>> I'm actually using a TCA0372, which is a dual 1-amp part.
> [ snip ]
>
>> The cartoon schematic in the data sheet doesn't show any
>> current limiting!
>
> The schematic is impossible (PNP in upper output pair),
> not fixed in dozens of revs, and still there in r11.
> Candidate for Bad Circuits.
But it is a great amp, and dirt cheap. I've used 3300 so far, no
problems.
That's what I like about electronics. We use physics, math, control
theory, simulation, data sheets, app notes, professional advice... and
you can't trust any of them.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics