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DC to 25Hz Isolated amplifier - 10KV Dielectric strenght

Hi all,

I have to build an iso amplifier with several KV dielectric strenght. DC(i. e 0hz) is mandatory. Please guys take a look at the schematic here down and be kind to comment i t if you have time for. (Spice sim could take a long time ...)

Version 4 SHEET 1 2044 820 WIRE -272 -368 -368 -368 WIRE -176 -368 -208 -368 WIRE -368 -272 -368 -368 WIRE -368 -272 -672 -272 WIRE -288 -272 -368 -272 WIRE -176 -272 -176 -368 WIRE -176 -272 -208 -272 WIRE -32 -272 -176 -272 WIRE 64 -272 -32 -272 WIRE 96 -272 64 -272 WIRE 192 -272 160 -272 WIRE -32 -256 -32 -272 WIRE 64 -208 64 -272 WIRE -32 -128 -32 -176 WIRE 64 -128 64 -144 WIRE 304 -96 272 -96 WIRE 432 -96 368 -96 WIRE 544 -96 432 -96 WIRE 624 -96 544 -96 WIRE 752 -96 704 -96 WIRE 816 -96 752 -96 WIRE 432 -80 432 -96 WIRE -288 -64 -288 -128 WIRE 544 -64 544 -96 WIRE 752 -64 752 -96 WIRE -608 -48 -608 -80 WIRE -176 -48 -176 -272 WIRE -672 -32 -672 -272 WIRE -640 -32 -672 -32 WIRE 192 -32 192 -272 WIRE 272 -32 272 -96 WIRE -512 -16 -576 -16 WIRE -352 -16 -432 -16 WIRE -976 0 -976 -48 WIRE -896 0 -976 0 WIRE -832 0 -896 0 WIRE -720 0 -752 0 WIRE -640 0 -720 0 WIRE -976 16 -976 0 WIRE -896 16 -896 0 WIRE -720 32 -720 0 WIRE -608 48 -608 16 WIRE 432 48 432 -16 WIRE 432 48 272 48 WIRE 544 48 544 16 WIRE 544 48 432 48 WIRE 752 48 752 0 WIRE 752 48 544 48 WIRE 816 48 752 48 WIRE -288 112 -288 32 WIRE -176 112 -176 16 WIRE -176 112 -288 112 WIRE -112 112 -176 112 WIRE 16 112 -32 112 WIRE 192 112 16 112 WIRE 384 112 272 112 WIRE 544 112 448 112 WIRE 656 112 544 112 WIRE 192 144 192 112 WIRE 272 144 272 112 WIRE -416 160 -416 144 WIRE 16 160 16 112 WIRE 544 160 544 112 WIRE 656 160 656 112 WIRE 16 240 16 224 WIRE -416 272 -416 240 WIRE -336 272 -416 272 WIRE -416 304 -416 272 WIRE 272 304 272 224 WIRE 544 304 544 240 WIRE 544 304 272 304 WIRE 656 304 656 224 WIRE 656 304 544 304 WIRE 752 304 752 48 WIRE 752 304 656 304 WIRE -176 384 -208 384 WIRE 0 384 -112 384 WIRE 112 384 80 384 WIRE 192 384 192 224 WIRE -416 400 -416 384 WIRE -208 464 -208 384 WIRE -128 464 -208 464 WIRE 112 464 112 384 WIRE 112 464 -48 464 WIRE 144 464 112 464 WIRE -208 496 -208 464 WIRE -208 640 -208 576 WIRE 192 640 192 480 WIRE -48 656 -80 656 WIRE 80 656 32 656 WIRE -80 704 -80 656 WIRE -80 704 -144 704 WIRE 80 720 80 656 WIRE 752 720 752 304 WIRE 752 720 80 720 WIRE -80 752 -80 704 WIRE -48 752 -80 752 WIRE 80 752 80 720 WIRE 80 752 16 752 FLAG 192 640 0 FLAG -208 640 0 FLAG -288 -128 P15V FLAG -608 -80 P15V FLAG 192 48 0 FLAG 64 -128 0 FLAG -32 -128 0 FLAG -720 96 0 FLAG -976 96 0 FLAG -416 144 P15V FLAG -144 704 0 FLAG 16 240 0 FLAG 816 -96 VOUT FLAG -416 400 N15V FLAG -336 272 0 FLAG -608 48 N15V FLAG -976 -48 VIN FLAG -896 96 0 FLAG 816 48 0V_VOUT SYMBOL ind2 176 64 M180 WINDOW 0 -49 77 Left 2 WINDOW 3 -73 40 Left 2 SYMATTR InstName L2

SYMATTR Type ind SYMATTR SpiceLine Rser=0.1 SYMBOL ind2 176 240 M180 WINDOW 0 -33 65 Left 2 WINDOW 3 -36 37 Left 2 SYMATTR InstName L1

SYMATTR Type ind SYMATTR SpiceLine Rser=0.1 SYMBOL ind2 288 64 R180 WINDOW 0 -41 70 Left 2 WINDOW 3 -67 35 Left 2 SYMATTR InstName L3

SYMATTR Type ind SYMATTR SpiceLine Rser=0.1 SYMBOL ind2 288 240 R180 WINDOW 0 -35 69 Left 2 WINDOW 3 -41 38 Left 2 SYMATTR InstName L4

SYMATTR Type ind SYMATTR SpiceLine Rser=0.1 SYMBOL voltage -208 480 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 3 13 105 Left 2 SYMATTR InstName V1 SYMATTR Value PULSE(0 8 0 100n 100n 5u 10u 10000) SYMBOL res -32 448 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 100 SYMBOL npn -352 -64 R0 SYMATTR InstName Q1 SYMATTR Value 2N3904 SYMBOL res -192 -288 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 20k5 SYMBOL Opamps\\LT1001A -608 -80 R0 SYMATTR InstName U1 SYMBOL res -416 -32 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 1k SYMBOL res -736 -16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R5 SYMATTR Value 20k5 SYMBOL cap -736 32 R0 SYMATTR InstName C1 SYMATTR Value 100p SYMBOL cap 48 -208 R0 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL schottky 160 -288 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL res -48 -272 R0 SYMATTR InstName R6 SYMATTR Value 5k SYMBOL voltage -416 144 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V3 SYMATTR Value 15 SYMBOL schottky 384 128 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D2 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 304 -80 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D3 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL res 528 -80 R0 SYMATTR InstName R7 SYMATTR Value 5k SYMBOL res 528 144 R0 SYMATTR InstName R8 SYMATTR Value 1k SYMBOL cap 416 -80 R0 SYMATTR InstName C4 SYMATTR Value 10n SYMBOL cap 640 160 R0 SYMATTR InstName C5 SYMATTR Value 200n SYMBOL nmos 144 384 R0 SYMATTR InstName M1 SYMATTR Value 2N7002 SYMBOL res -16 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 100 SYMBOL cap -192 -48 R0 SYMATTR InstName C3 SYMATTR Value 100n SYMBOL voltage -416 288 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V4 SYMATTR Value 15 SYMBOL cap 0 160 R0 SYMATTR InstName C6

SYMBOL cap -208 -384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 100n SYMBOL cap -112 368 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 500p SYMBOL res 96 368 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 100 SYMBOL current -976 96 R180 WINDOW 3 -457 -58 Left 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName I1 SYMATTR Value SINE(8m 4m 25 0 0 0 100) SYMBOL res -912 0 R0 SYMATTR InstName R10 SYMATTR Value 500 SYMBOL res 48 640 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R11 SYMATTR Value 1meg SYMBOL cap 16 736 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C9 SYMATTR Value 0.1n SYMBOL res 720 -112 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R12 SYMATTR Value 10k SYMBOL cap 736 -64 R0 SYMATTR InstName C10 SYMATTR Value 1n TEXT 216 -160 Left 2 !K L1 L2 L3 L4 0.97 TEXT -936 312 Left 2 !.tran 400m startup TEXT -936 360 Left 2 !;tran 1 startup TEXT -936 392 Left 2 !;ac dec 100 1 100 TEXT -1592 -352 Left 6 ;ISO AMP RECTANGLE Normal 224 816 -1248 -400 2

Reply to
habib.bouaziz
Loading thread data ...

From the .ASC you sent looks like you only need unipolar output, in other words a 0 to +10V input makes isolated 0 to +10V output. Since you only need low speed have you considered just using PWM? Gate the isolated converter so it runs 100% of the time for max input and proportionly less down to zero input. That way you might get away with just a single primary and single secondary winding and simpler feedback.

piglet

Reply to
piglet

Just to clarify - when I suggested PWM I do not mean PWM at the converter transformer operating carrier frequency (say 100kHz) I really meant PWM at a lower rate (say 0.5 - 3kHz) but high enough so that after filtering it can still reproduce your 25Hz signals.

piglet

Reply to
piglet

Utter garbage! Who the hell even pays you? Has to be some kind of welfare program...

Reply to
bloggs.fredbloggs.fred

Who the hell even pays you? Has to be some kind of welfare program...

You answer first, Mr. Fred Blobbs.

Reply to
John S

rote:

C(i.e 0hz) is mandatory.

nt it if you have time for. (Spice sim could take a long time ...)

program...

You're some sort of narcisic pervers. I repeat you may ignore my posts to k eep you happy. I remember someone suggesting me to ignore your assaults. I will, i promise.

H.

Reply to
habib.bouaziz

C(i.e 0hz) is mandatory.

Ok i will thinking about PWM process. Thx

Reply to
habib.bouaziz

Den torsdag den 22. januar 2015 kl. 16.01.42 UTC+1 skrev snipped-for-privacy@gmail.com:

snip

why not something like an IL300 and two opamps?

formatting link

-Lasse

Reply to
Lasse Langwadt Christensen

Are you back, and this after being voted most ignorable troll (mit) ?

Reply to
bloggs.fredbloggs.fred

On Thursday, January 22, 2015 at 11:51:14 AM UTC-5, snipped-for-privacy@gmail.com wro te:

DC(i.e 0hz) is mandatory.

ment it if you have time for. (Spice sim could take a long time ...)

re program...

keep you happy. I remember someone suggesting me to ignore your assaults. I will, i promise.

Your circuit is garbage, can't imagine what use it could be put to other th an to help occupy the time of mentally ill institutionalized electronics te chs.

Reply to
bloggs.fredbloggs.fred

Learn how to killfile... it's an ulcer preventative ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142     Skype: skypeanalog  |             | 
| 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 to
Jim Thompson

It requires that you get a real newsreader, not Google Groups -- but it's worth it.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

He needs more than the data sheet's claimed isolation.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

I didn't look at the schematic, but I gather you have a transformer in there.

Why not use an LED/photodiode pair, and PWM? Things should work fine down to DC, and 25Hz should be easy to achieve. You can implement the optical connection with as much standoff as you need, and if necessary for other reasons you can shield it (i.e., fire the light down a black plastic tube of suitable length).

You didn't mention what precision you need -- that'll help us help you.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

I need to withstand 10KV DC/1min, AFAIK no opto device could fulfill this requirement. The accuracy over the range 4/20mA is something as 1%.

I could not post my MathCAD results, the tricky point is the transformer specs itself. I will launch a PCB for evaluate this so i'm quite confident.

As mentioned above by piglet, an interresting idea is to transform my primary circuit to a PWM-based one... i will see.

Thx, Habib.

>
Reply to
Habib Bouaziz-Viallet

I know how to put Bloggs into my KillFile but my trash is not dirty enough to put that sh...it in it !

Habib.

Reply to
Habib Bouaziz-Viallet

I told him that his mother should have been imprisoned for failing to flush him.

Reply to
DecadentLinuxUserNumeroUno

It didn't take me 30 seconds to fully spec out a low cost solution to your low tech project ...you're laughable, and probably overcomplicating and underperforming just to put hours, if not weeks and months, on the clock.

Reply to
bloggs.fredbloggs.fred

25Hz? I seriously doubt it.

I would bet money that you did no such thing, and also now that you have no capacity to properly time an event sequence, because your 30 second claim would be argued as an outright lie by anyone and everyone.

Reply to
DecadentLinuxUserNumeroUno

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My variant on that was to use transformer to transmit a fixed DC voltage un til the core got to - say - 70% of saturation, after which I used a track a nd hold on the output side to maintain the output while I reduced the curre nt through transformer as fast as possible until I'd got to 70% of saturati on in the other direction (which took a couple of milliseconds).

I only used it with a unipolar 1V to 5V process control signal, and it work ed fine. IIRR at 5V I was running about 70% track to 30% hold with the syst em cycling at about 100Hz, but this was all back in 1974, so the details ar e a bit hazy.

As far as I can see, it would work fine with a bipolar signal - you'd have to add a parallel signal path to tell the output track and hold when to swi tch from track to hold (which I didn't need when transmitting a a reliably positive signal).

The advantage over PWM is that the scheme transmitted an absolute voltage d ifference (which with the right 1:1 transformer could be accurate to 10 ppb ).

--
Bill Sloman, Sydney
Reply to
Bill Sloman

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