Hysteresis without Feedback

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I've succeeded in creating a hysteresis element that doesn't use
feedback to accomplish the hysteresis...

<
http://www.analog-innovations.com/DeviceModelsSubckts/Hysteresis_Without_Feedback_2017-07-13.png


which means...




need for a built-into-the-Spice-engine device model, e.g., a
Jiles-Atherton model capability.

Will post the whole enchilada once the 'refining' exercise is
complete... RSN ;-)
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On Thursday, 13 July 2017 22:37:22 UTC+1, Jim Thompson  wrote:

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_Feedback_2017-07-13.png>
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he

I'm not making much sense of the circuit, which is partly covered by the ou
tput graph. What sort of circuit is it?


Hysteresis without feedback:

.               +
.               |
.               R
.     |>|      _|----o out
. ----|<| +--||_
.         |     |
.         C     |
. ________|_____|____ 0v


That input thing is 2 parallel diodes.


NT

Re: Hysteresis without Feedback
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Doesn't work for the DC sweep shown. :^)

Tim

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Electrical Engineering Consultation and Contract Design
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Re: Hysteresis without Feedback
On Thu, 13 Jul 2017 15:46:14 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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Close ;-)
        
                                        ...Jim Thompson
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| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On Friday, 14 July 2017 00:18:34 UTC+1, Jim Thompson  wrote:
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out_Feedback_2017-07-13.png>
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t the
 output graph. What sort of circuit is it?
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I'm doing something wrong here, but not seeing what...


Version 4
SHEET 1 880 680
WIRE -704 -48 -784 -48
WIRE -48 -48 -704 -48
WIRE -784 -32 -784 -48
WIRE -704 -16 -704 -48
WIRE -784 64 -784 48
WIRE -704 64 -704 48
WIRE -48 128 -48 -48
WIRE -48 288 -48 208
WIRE -448 368 -560 368
WIRE -192 368 -256 368
WIRE -96 368 -192 368
WIRE -192 400 -192 368
WIRE -448 432 -448 368
WIRE -256 432 -256 368
WIRE -192 496 -192 464
WIRE -48 496 -48 384
WIRE -48 496 -192 496
WIRE -560 528 -560 448
WIRE -48 528 -48 496
FLAG -784 64 0
FLAG -48 528 0
FLAG -704 64 0
FLAG -560 528 0
SYMBOL voltage -784 -48 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=0
SYMATTR InstName V1
SYMATTR Value 10
SYMBOL cap -720 -16 R0
SYMATTR InstName C1

SYMBOL nmos -96 288 R0
SYMATTR InstName M1
SYMBOL res -64 112 R0
SYMATTR InstName R1
SYMATTR Value 100
SYMBOL cap -208 400 R0
SYMATTR InstName C2
SYMATTR Value 0.1
SYMBOL diode -320 384 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMBOL diode -384 384 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D2
SYMBOL diode -448 384 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMBOL diode -256 416 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D4
SYMBOL diode -320 416 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D5
SYMBOL diode -384 416 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D6
SYMBOL voltage -560 352 M0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(-10 15 0 .1 .1 0 0 1)
TEXT -608 -88 Left 2 !.tran 0 0.2 0 10u startup


NT

Re: Hysteresis without Feedback
On Thu, 13 Jul 2017 17:34:23 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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The trick, as always, is in using TANH ;-)
        
                                        ...Jim Thompson
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| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On Thu, 13 Jul 2017 17:36:02 -0700, Jim Thompson

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Plus LTspice's idealized elements will cook your goose, because
they're idealized around the needs of SMPS's.
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On Friday, 14 July 2017 01:45:56 UTC+1, Jim Thompson  wrote:
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Without_Feedback_2017-07-13.png>
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thout the
 the output graph. What sort of circuit is it?
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I don't have any TANHs in stock at the moment :) None in the junkbox either
.


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The effect I'm playing with is very simple, spice models the diode V drop n
ear enough for the purpose. But the output stays at +10v, and I'm not seein
g why. Even when Vg ranges over -10 to +12v.


NT

Re: Hysteresis without Feedback
On Thu, 13 Jul 2017 17:54:25 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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Whatever NMOS model you picked only sucks 1.5mA at full drive.
        
                                        ...Jim Thompson
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| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On Friday, 14 July 2017 02:34:52 UTC+1, Jim Thompson  wrote:
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e
is_Without_Feedback_2017-07-13.png>
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 without the
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 by the output graph. What sort of circuit is it?
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her.
p near enough for the purpose. But the output stays at +10v, and I'm not se
eing why. Even when Vg ranges over -10 to +12v.
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Bingo, thank you. Changed R to 10k and it works.

Spice plots Vin & Vout vs t, I don't know how to plot Vin vs Vout though.


NT

Re: Hysteresis without Feedback
On Thu, 13 Jul 2017 18:41:27 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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In PSpice you just click change x-axis variable and select what you
want from the list, or type it in if you already know.

I think there's an equivalent in LTspice (I don't create schematics in
LTspice, just do a Run, Filename, to verify results are the same in
LTspice as in PSpice).
        
                                        ...Jim Thompson
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| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
snipped-for-privacy@gmail.com wrote:
  
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Many problems. You don't need C1 - it is in parallel with a zero ohm  
source voltage. C2 is 0.1 Farad. That's way too large, and there is no  
readon to add it in parallel with the gate capacitance. Delete it.

The biggest problem is the MOSFET. Since you did not select a real  
device, it defaults to a very small device that cannot carry much  
current. So you won't see much output change across a 100 ohm load.

Next, you should never use the default semiconductors unless there is a  
reason to do so. Change D1-D6 to valid diodes.

You should always label every node in the circuit. If you do not, Ltspice  
will renum,er the nodes every time you make a change. If you were trying  
to plot N00X, the waveform will show some other part of the circuit.

Finally, to see the effect of gate capacitance, increase the signal  
frequency drastically.

Try this version:

Version 4
SHEET 1 880 680
WIRE -48 96 -272 96
WIRE -272 112 -272 96
WIRE -48 128 -48 96
WIRE -272 208 -272 192
WIRE -48 240 -48 208
WIRE -48 288 -48 240
WIRE -512 368 -560 368
WIRE -448 368 -512 368
WIRE -144 368 -256 368
WIRE -96 368 -144 368
WIRE -560 400 -560 368
WIRE -448 432 -448 368
WIRE -256 432 -256 368
WIRE -560 528 -560 480
WIRE -48 528 -48 384
FLAG -272 208 0
FLAG -48 528 0
FLAG -560 528 0
FLAG -48 240 M1D
FLAG -144 368 M1G
FLAG -512 368 Vgate
SYMBOL voltage -272 96 R0
WINDOW 123 0 0 Left 2
WINDOW 39 37 59 Left 2
SYMATTR SpiceLine Rser=0
SYMATTR InstName V1
SYMATTR Value 10
SYMBOL nmos -96 288 R0
SYMATTR InstName M1
SYMATTR Value IRF530
SYMBOL res -64 112 R0
SYMATTR InstName R1
SYMATTR Value 100
SYMBOL schottky -320 384 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMATTR Value 1N4007
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL diode -384 384 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D2
SYMATTR Value 1N4007
SYMBOL diode -448 384 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4007
SYMBOL diode -256 416 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D4
SYMATTR Value 1N4007
SYMBOL diode -320 416 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D5
SYMATTR Value 1N4007
SYMBOL diode -384 416 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D6
SYMATTR Value 1N4007
SYMBOL voltage -560 384 M0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 10 0 2u 2u 0 0)
TEXT -568 32 Left 2 !.tran 0 220u 200u
TEXT -568 8 Left 2 ;'MOSFET Gate Driver
TEXT -344 32 Left 2 !.ic V(M1G) = 0

Re: Hysteresis without Feedback
On Friday, 14 July 2017 02:37:58 UTC+1, Steve Wilson  wrote:
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Ha, yes. I just didn't bother to delete it, makes no difference.

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Sure. I put it there in case the fet model has leakage added.

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Their Vf is a fixed 1v drop. For this proof of concept it doesn't matter.

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or remove the capacitor, as it works using gate capacitance already. Again it was just a quick proof of concept, since it ran in around a second I didn't worry about the time scale.


NT

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Re: Hysteresis without Feedback
On 14/07/2017 02:37, Steve Wilson wrote:
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D1 is a schottky 1N4007 - does that confuse things??

piglet



Re: Hysteresis without Feedback
wrote:

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1N4007 is NOT a Schottky.
        
                                        ...Jim Thompson
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| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On 14/07/2017 17:34, Jim Thompson wrote:
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Precisely!

piglet


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Re: Hysteresis without Feedback
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IOW you don't own any transistors. ;)

A BJT diff pair with its output taken differentially has a tanh characteristic. It's surprisingly accurate if you use monolithically-matched devices.  

Cheers

Phil Hobbs

Re: Hysteresis without Feedback
On Friday, 14 July 2017 03:19:35 UTC+1, snipped-for-privacy@gmail.com  wrote:
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I just rechecked my stocks. Where did all those tanhs come from?


NT

Re: Hysteresis without Feedback
On Thu, 13 Jul 2017 19:19:30 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

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Yup, the basis for my very first patent...

   3,491,301 Integrated Harmonic Mixer
        
                                        ...Jim Thompson
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| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: Hysteresis without Feedback
On 14/07/2017 01:36, Jim Thompson wrote:
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TANH implies a differential pair? So isn't there feedback action at the  
common emitter junction?

piglet


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