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I can't see that as happening. If the 12V supply current limits by suppling less than 12V, the MOSFETs still have to get enough voltage to keep them turned on, and if they sit for an appreciable at the lower voltage, drawing a current that the power supply can sustain, a relatively slow start-up doesn't get to be problem until you cook the MOSFETs.

Exploring what happens at lower supply voltages - 10V and 12V rather than 15V - you get a longer dwell time at a lower current - 140mA at

10V for 300usec, 280mA for 150usec at 12V - for a tolerably constant 0.21mJ in the transistors.

Presumably what you are seeing is the circuit building up to the 0.3mJ you've got stored in the tank circuit when it's running steadily from

15V (0.2mJ at 12V, 0.13mJ at 10V).

This sort of thermal load seems to be adequately within the single pulse rating of the 2n7002, if the NXP data sheet is to be relied on

You'd be an order of magnitude short of blowing up the part - 280mA through one transistor would blow one up in 1msec - so it looks tolerably safe.

Me too - albeit for a CD ignition for my car back in 1970. It does seem to be obvious to those skilled in the art.

-- Bill Sloman, Nijmegen

On a sunny day (Mon, 26 Sep 2011 20:53:26 -0700) it happened John Larkin wrote in :

Some deep insight there ;-) hehe LOL

On Sep 27, 3:02=A0am, John Larkin wrote:

Here's what happens with a quick and dirty current-limited power supply

Version 4 SHEET 1 1316 736 WIRE -80 0 -160 0 WIRE 64 0 -80 0 WIRE 288 0 144 0 WIRE 368 0 288 0 WIRE -160 96 -160 0 WIRE -112 96 -160 96 WIRE 96 96 -32 96 WIRE 256 96 96 96 WIRE 368 96 368 0 WIRE 368 96 336 96 WIRE -112 192 -160 192 WIRE 16 192 -32 192 WIRE 256 192 16 192 WIRE 368 192 336 192 WIRE -368 256 -464 256 WIRE -208 256 -288 256 WIRE 16 256 16 192 WIRE 16 256 -208 256 WIRE -464 336 -464 256 WIRE -160 400 -160 192 WIRE -80 400 -160 400 WIRE 0 400 -80 400 WIRE 288 400 64 400 WIRE 368 400 368 192 WIRE 368 400 288 400 WIRE -160 448 -160 400 WIRE -16 448 -160 448 WIRE 144 480 -48 480 WIRE 368 480 368 400 WIRE 368 480 224 480 WIRE -160 496 -160 448 WIRE 368 496 368 480 WIRE -48 576 -48 480 WIRE -48 576 -112 576 WIRE -16 576 -16 448 WIRE 176 576 -16 576 WIRE 320 576 256 576 WIRE -464 624 -464 416 WIRE -160 624 -160 592 WIRE -160 624 -464 624 WIRE 96 624 96 96 WIRE 96 624 -160 624 WIRE 368 624 368 592 WIRE 368 624 96 624 WIRE -464 656 -464 624 FLAG -464 656 0 FLAG -208 256 Vct FLAG 288 0 Vout+ FLAG -80 0 Vout- FLAG -80 400 tank- FLAG 288 400 tank+ SYMBOL ind2 -128 208 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 0.00025 SYMATTR Type ind SYMATTR SpiceLine Rser=3D0.022 SYMBOL ind2 240 208 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L2 SYMATTR Value 0.00025 SYMATTR Type ind SYMATTR SpiceLine Rser=3D0.022 SYMBOL nmos 320 496 R0 SYMATTR InstName M1 SYMATTR Value FDS6680A SYMBOL nmos -112 496 M0 SYMATTR InstName M2 SYMATTR Value FDS6680A SYMBOL cap 64 384 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 46 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 100n SYMBOL ind -384 272 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L3 SYMATTR Value 0.001 SYMATTR SpiceLine Rser=3D0.044 Cpar=3D100p SYMBOL voltage -464 320 R0 WINDOW 123 0 0 Left 2 WINDOW 39 24 132 Left 2 SYMATTR SpiceLine Rser=3D0.001 SYMATTR InstName V1 SYMATTR Value 5 SYMBOL res 272 560 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10 SYMBOL res 240 464 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 10 SYMBOL ind2 -128 112 R270 WINDOW 0 44 45 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L4 SYMATTR Value 0.0000253 SYMATTR Type ind SYMATTR SpiceLine Rser=3D0.004 Cpar=3D100pF SYMBOL ind2 240 112 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L5 SYMATTR Value 0.0000253 SYMATTR Type ind SYMATTR SpiceLine Rser=3D0.004 SYMBOL res 160 -16 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 10k TEXT -400 664 Left 2 !.tran 0 15m 1m 10n TEXT -448 8 Left 2 !K1 L1 L2 0.99 TEXT -448 40 Left 2 !K2 L1 L4 0.99 TEXT -448 72 Left 2 !K3 L1 L5 0.99 TEXT -448 104 Left 2 !K4 L2 L4 0.99 TEXT -448 136 Left 2 !K5 L2 L5 0.99 TEXT -448 168 Left 2 !K6 L4 L5 0.99 TEXT -472 704 Left 2 !.ic V(tank-)=3D0 V(Vct)=3D0.8 V(tank+)=3D1.6

The gate voltage dividers - R1/R3 and R2/R4 - have been changed so that the circuit starts up with about 5V at the centre-tap,

As drawn, it starts up with about 154mA in each transistor, which is just on the transistor's DC dissipation limit with 5V drain-to-source. A small dose of fold-back could guarantee them infinite time to start up at a lower current.

This strikes me as a way of dealing with the start-up anxiety - whether it would, in fact, fit into your circuit is a different question which I can't answer.

-- Bill Sloman, Nijmegen

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Thanks, I couldn't find the FET on digikey, so I asked.

George H.

Virtually all this stuff is prior art. Like Baxandall oscillators, for example. Or using transistors backwards, etc.

New uses might not be prior art. Maybe Bill can cite us a patent number for a voltage multiplier using a resonant tank for said multiplication.

Not that it matters. What matters is what's useful, and works. It doesn't matter if MOSFETs have been used as switches before, it's what you do with them. That's the fun.

-- Cheers, James Arthur

I understand Baxandall oscillators but have never heard of using transistors "backwards". Could you elaborate?

Thanks,

Jim

I'm not surprised they're a bit ugly--you have to hit stuff pretty hard to get x-rays.

Cheers

Phil Hobbs

If you switch emitter and collector of a garden-variety transistors, you get tansistors with a break-down voltage below 10 V and lousy beta, but with extremely low saturation voltage.

About 40 years ago, we used them as switches in a R/2R ladder for a D/A converter, as there were no FETs available yet.

For more information, Google for Ebers-Moll model.

--

Tauno Voipio

This looks pretty good. The flyback could make, say, 120 DC. The depletion fet pushes a constant current, like 0.75 mA maybe, into the zener stack.

ftp://jjlarkin.lmi.net/EUV_HV_supply.JPG

If I make the inductor big and the gate resistor big, it will switch slow and will be quiet and efficiency will be terrible.

John

No EnergyStar label for that one :-)

You'll be burning around 100mW in the zeners. Not so nice, even in three SOT23 packages. The bias voltage will be somewhat "nervous" and have a high lot-to-lot tolerance because of the zeners.

Maybe something like they have hanging off of the gate of VT2 in figure

12 here:

You could use the LMV431 so the minimum current can be set to around

0.1mA instead of 0.75mA. Tambien es mucho mas tranquilo.

--
Regards, Joerg

http://www.analogconsultants.com/

Yep, that's it. "Inverted mode," we call it. I've got measurements I took for common BJTs somewhere... Vce(sat) < 2mV, IIRC.

-- Cheers, James Arthur

Tauno got the main odd use of BJTs, but you can also use them as zeners, varactors, negative resistance oscillators (with base open), avalanche switches, ultra-low leakage diodes, and strobe lights(*).

(*) Once.

-- Cheers, James Arthur

Temperature sensors, heaters, noise sources, light sources (low level), IR sources, fuses, RF oscillators (unintentional), engineer interview rejection machine.

Nice RF oscillator/interview booby trap:

+10 | | | c +5V----------b e | | 330r | | | gnd

John

Makes no sense. There's no gate dividers, and it starts at 45 amps.

John

On Sep 28, 3:32=A0am, John Larkin wrote:

Here's - hopefully - the circuit I thought I was posting

Version 4 SHEET 1 2008 1264 WIRE -48 16 -320 16 WIRE 128 16 -48 16 WIRE 256 16 208 16 WIRE -48 64 -48 16 WIRE 128 128 96 128 WIRE 256 128 256 16 WIRE 256 128 208 128 WIRE 320 128 256 128 WIRE 432 128 400 128 WIRE -320 144 -320 16 WIRE 96 192 96 128 WIRE 224 192 96 192 WIRE 432 192 432 128 WIRE 432 192 288 192 WIRE 512 192 432 192 WIRE 704 192 592 192 WIRE 832 192 768 192 WIRE 864 192 832 192 WIRE 976 192 928 192 WIRE 1104 192 976 192 WIRE 1104 224 1104 192 WIRE -320 240 -320 224 WIRE -48 240 -48 128 WIRE -48 240 -320 240 WIRE 96 240 96 192 WIRE 832 240 832 192 WIRE 976 240 976 192 WIRE -320 256 -320 240 WIRE 432 272 432 192 WIRE 96 336 96 240 WIRE 512 336 96 336 WIRE 832 336 832 304 WIRE 832 336 592 336 WIRE 976 368 976 304 WIRE 1104 368 1104 304 WIRE 96 416 96 336 WIRE 144 416 96 416 WIRE 256 416 224 416 WIRE 304 416 288 416 WIRE 432 416 432 272 WIRE 432 416 384 416 WIRE 96 464 96 416 WIRE 432 464 432 416 WIRE 288 496 288 416 WIRE 288 496 208 496 WIRE 176 544 144 544 WIRE 208 544 208 496 WIRE 208 544 176 544 WIRE 256 544 256 416 WIRE 336 544 256 544 WIRE 384 544 336 544 WIRE 96 608 96 560 WIRE 208 608 208 544 WIRE 256 608 256 544 WIRE 432 608 432 560 WIRE 208 752 208 688 WIRE 256 752 256 688 FLAG 96 608 0 FLAG 432 608 0 FLAG -320 256 0 FLAG 208 752 0 FLAG 256 752 0 FLAG 976 368 0 FLAG 1104 368 0 FLAG 96 240 n003 FLAG 432 272 n004 FLAG 256 16 n002 FLAG 336 544 n007 FLAG 176 544 n008 SYMBOL ind2 112 144 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 33=B5 SYMBOL ind2 304 144 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L2 SYMATTR Value 33=B5 SYMBOL ind 112 32 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L3 SYMATTR Value 130=B5 SYMBOL nmos 384 464 R0 WINDOW 0 133 16 Left 2 WINDOW 3 109 51 Left 2 SYMATTR InstName M1 SYMATTR Value 2N7002 SYMBOL cap 288 176 R90 WINDOW 0 72 35 VBottom 2 WINDOW 3 79 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 330n SYMBOL res 240 400 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 3K SYMBOL res 400 400 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 3K SYMBOL voltage -320 128 R0 WINDOW 0 64 35 Left 2 WINDOW 3 64 63 Left 2 WINDOW 123 0 0 Left 2 WINDOW 39 64 91 Left 2 SYMATTR InstName V1 SYMATTR Value 115 SYMATTR SpiceLine Rser=3D360 SYMBOL res 240 592 R0 WINDOW 0 64 58 Left 2 WINDOW 3 62 95 Left 2 SYMATTR InstName R3 SYMATTR Value 4k7 SYMBOL res 192 592 R0 WINDOW 0 -65 57 Left 2 WINDOW 3 -69 94 Left 2 SYMATTR InstName R4 SYMATTR Value 4k7 SYMBOL cap 768 176 R90 WINDOW 0 -50 32 VBottom 2 WINDOW 3 -40 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 330n SYMBOL cap 992 304 R180 WINDOW 0 -49 44 Left 2 WINDOW 3 -45 7 Left 2 SYMATTR InstName C3 SYMATTR Value 1 SYMBOL diode 848 304 R180 WINDOW 0 72 52 Left 2 WINDOW 3 53 13 Left 2 SYMATTR InstName D1 SYMATTR Value GSD2004W-V SYMBOL diode 864 208 R270 WINDOW 0 84 18 VTop 2 WINDOW 3 70 30 VBottom 2 SYMATTR InstName D2 SYMATTR Value GSD2004W-V SYMBOL res 1088 208 R0 WINDOW 0 67 53 Left 2 WINDOW 3 59 88 Left 2 SYMATTR InstName R5 SYMATTR Value 100K SYMBOL nmos 144 464 M0 SYMATTR InstName M2 SYMATTR Value 2N7002A SYMBOL res 608 176 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R6 SYMATTR Value 1k SYMBOL res 608 320 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 1k SYMBOL zener -32 128 R180 WINDOW 0 24 72 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D3 SYMATTR Value BZX84C15L TEXT 288 48 Left 2 !K1 L1 L2 1 TEXT -472 808 Left 2 !.tran 20m TEXT -480 840 Left 2 !.model 2N7002A VDMOS(Rg=3D3 Vto=3D1.61 Rd=3D0 Rs=3D.7=

5 Rb=3D.14 Kp=3D.17 mtriode=3D1.25 Cgdmax=3D80p Cgdmin=3D12p Cgs=3D50p Cjo=3D= 50p Is=3D. 04p mfg=3DFairchild Vds=3D60 Ron=3D2 Qg=3D1.5n)

Sorry about that. I managed to cut and paste the wrong .asc file. This one apppears to be the one I intended to post - it has at least got the gate dividers.

Thinking about it, limiting the current at 278mA doesn't make much sense - the DC drain when the circuit is running is about 80mA, so a DC current limit of about 100mA, and a big enough reservoir capacitor

- maybe 10uF - would make start-up perfectly safe, no matter how long it took.

-- Bill Sloman, Nijmegen

Not very practical, an oscillator that needs a separate current limiter, plus R6 and R7, plus custom-teased gate voltages, to start up.

John

Try what i have seen for decades in similar circumstances, bulk type HV = or multiplier followed by a quiet skimmer linear regulator.

?=3D)

On a sunny day (Tue, 27 Sep 2011 14:10:45 -0700 (PDT)) it happened snipped-for-privacy@yahoo.com wrote in :

And to keep a table level ;-)

On Sep 28, 4:35 am, John Larkin wrote:

When I finally got around to checking that the voltage doubler was actually working, that part of the circuit turned out to have gotten corrupted. With a voltage doubler that actually works, R6 and R7 turn out to be unnecessary.

The gate voltages aren't custom-teased. The 3k/4k7 just makes sure that the maximum gate-source voltage is less than 30V when the circuit is delivery 90V at the output of the voltage doubler

The current limiting power supply - presumably a single LDO chip (I use the LT3050EMSE#PBF below though it isn't cheap, and doesn't seem to be doing quite what is claimed) limits the start-up voltage and thus the gate drive to the MOSFETs during start-up, to a level that matches the current limit - so it "auto-teases" during start-up. There are other ways of getting this kind of behaviour - a small LDO regulator chip with a thermal protection circuit would presumably have the same kind of thermal mass as the 2N7002 transistors, and could be relied on to limit the supply current during start-up to a safe level on the basis of its own self-heating, which could save a few resistors

Version 4 SHEET 1 2008 1264 WIRE -528 16 -800 16 WIRE -64 16 -272 16 WIRE 32 16 -64 16 WIRE 192 16 32 16 WIRE 320 16 272 16 WIRE -64 48 -64 16 WIRE -800 112 -800 16 WIRE -528 112 -800 112 WIRE -224 112 -272 112 WIRE 192 128 160 128 WIRE 320 128 320 16 WIRE 320 128 272 128 WIRE 384 128 320 128 WIRE 496 128 464 128 WIRE -800 160 -800 112 WIRE 496 176 496 128 WIRE 624 176 496 176 WIRE 768 176 624 176 WIRE 848 176 832 176 WIRE 896 176 848 176 WIRE 928 176 896 176 WIRE 1040 176 992 176 WIRE 1120 176 1040 176 WIRE 1168 176 1120 176 WIRE 160 192 160 128 WIRE 288 192 160 192 WIRE 496 192 496 176 WIRE 496 192 352 192 WIRE -224 224 -224 112 WIRE -64 224 -64 128 WIRE -64 224 -224 224 WIRE 1168 224 1168 176 WIRE 160 240 160 192 WIRE 896 240 896 176 WIRE 1040 240 1040 176 WIRE 496 272 496 192 WIRE -608 304 -720 304 WIRE -528 304 -608 304 WIRE -272 304 -272 288 WIRE -144 304 -272 304 WIRE -64 336 -64 224 WIRE 160 368 160 240 WIRE 624 368 160 368 WIRE 752 368 688 368 WIRE 896 368 896 304 WIRE 896 368 752 368 WIRE -224 400 -272 400 WIRE -720 416 -720 304 WIRE -608 416 -608 304 WIRE 160 416 160 368 WIRE 208 416 160 416 WIRE 320 416 288 416 WIRE 368 416 352 416 WIRE 496 416 496 272 WIRE 496 416 448 416 WIRE 160 464 160 416 WIRE 496 464 496 416 WIRE -144 480 -144 304 WIRE 352 496 352 416 WIRE 352 496 272 496 WIRE 752 528 752 368 WIRE 240 544 208 544 WIRE 272 544 272 496 WIRE 272 544 240 544 WIRE 320 544 320 416 WIRE 400 544 320 544 WIRE 448 544 400 544 WIRE 32 608 32 16 WIRE 272 608 272 544 WIRE 320 608 320 544 WIRE -800 736 -800 240 WIRE -720 736 -720 480 WIRE -720 736 -800 736 WIRE -608 736 -608 496 WIRE -608 736 -720 736 WIRE -224 736 -224 400 WIRE -224 736 -608 736 WIRE -144 736 -144 544 WIRE -144 736 -224 736 WIRE -64 736 -64 416 WIRE -64 736 -144 736 WIRE 32 736 32 672 WIRE 32 736 -64 736 WIRE 160 736 160 560 WIRE 160 736 32 736 WIRE 272 736 272 688 WIRE 272 736 160 736 WIRE 320 736 320 688 WIRE 320 736 272 736 WIRE 496 736 496 560 WIRE 496 736 320 736 WIRE 752 736 752 592 WIRE 752 736 496 736 WIRE 1040 736 1040 304 WIRE 1040 736 752 736 WIRE 1168 736 1168 304 WIRE 1168 736 1040 736 WIRE -800 752 -800 736 FLAG -800 752 0 FLAG 160 240 n003 FLAG 496 272 n004 FLAG 320 16 n002 FLAG 400 544 n007 FLAG 240 544 n008 FLAG 1120 176 n011 FLAG 848 176 n010 FLAG 624 176 n009 SYMBOL ind2 176 144 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 33=B5 SYMBOL ind2 368 144 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 4 56 VBottom 2 SYMATTR InstName L2 SYMATTR Value 33=B5 SYMBOL ind 176 32 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L3 SYMATTR Value 130=B5 SYMBOL nmos 448 464 R0 WINDOW 0 133 16 Left 2 WINDOW 3 109 51 Left 2 SYMATTR InstName M1 SYMATTR Value 2N7002 SYMBOL cap 352 176 R90 WINDOW 0 72 35 VBottom 2 WINDOW 3 79 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 330n SYMBOL res 304 400 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 3K SYMBOL res 464 400 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 3K SYMBOL voltage -800 144 R0 WINDOW 0 64 35 Left 2 WINDOW 3 64 63 Left 2 WINDOW 123 0 0 Left 2 WINDOW 39 64 91 Left 2 SYMATTR InstName V1 SYMATTR Value PULSE(0 16 0 1m 1m 50m) SYMBOL res 304 592 R0 WINDOW 0 64 58 Left 2 WINDOW 3 62 95 Left 2 SYMATTR InstName R3 SYMATTR Value 4k7 SYMBOL res 256 592 R0 WINDOW 0 -65 57 Left 2 WINDOW 3 -69 94 Left 2 SYMATTR InstName R4 SYMATTR Value 4k7 SYMBOL cap 832 160 R90 WINDOW 0 -50 32 VBottom 2 WINDOW 3 -40 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 330n SYMBOL cap 1056 304 R180 WINDOW 0 -49 44 Left 2 WINDOW 3 -45 7 Left 2 SYMATTR InstName C3 SYMATTR Value 1=B5 SYMBOL diode 912 304 R180 WINDOW 0 72 52 Left 2 WINDOW 3 -118 -21 Left 2 SYMATTR InstName D1 SYMATTR Value GSD2004W-V SYMBOL diode 928 192 R270 WINDOW 0 84 18 VTop 2 WINDOW 3 70 30 VBottom 2 SYMATTR InstName D2 SYMATTR Value GSD2004W-V SYMBOL res 1152 208 R0 WINDOW 0 67 53 Left 2 WINDOW 3 59 88 Left 2 SYMATTR InstName R5 SYMATTR Value 100k SYMBOL nmos 208 464 M0 SYMATTR InstName M2 SYMATTR Value 2N7002A SYMBOL PowerProducts\\LT3050 -400 208 R0 SYMATTR InstName U1 SYMBOL res -624 400 R0 SYMATTR InstName R8 SYMATTR Value 1150 SYMBOL cap -736 416 R0 SYMATTR InstName C4 SYMATTR Value 10nF SYMBOL res -80 32 R0 SYMATTR InstName R9 SYMATTR Value 630k SYMBOL res -80 320 R0 SYMATTR InstName R10 SYMATTR Value 27k SYMBOL cap 16 608 R0 SYMATTR InstName C5 SYMATTR Value 2.2=B5 SYMBOL diode 768 592 R180 WINDOW 0 72 52 Left 2 WINDOW 3 -118 -21 Left 2 SYMATTR InstName D3 SYMATTR Value GSD2004W-V SYMBOL cap 688 352 R90 WINDOW 0 -50 32 VBottom 2 WINDOW 3 -40 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 330n SYMBOL cap -160 480 R0 SYMATTR InstName C7 SYMATTR Value 10nF TEXT 352 48 Left 2 !K1 L1 L2 1 TEXT -808 816 Left 2 !.tran 20m TEXT -808 848 Left 2 !.model 2N7002A VDMOS(Rg=3D3 Vto=3D1.61 Rd=3D0 Rs=3D.7=

5 Rb=3D.14 Kp=3D.17 mtriode=3D1.25 Cgdmax=3D80p Cgdmin=3D12p Cgs=3D50p Cjo=3D= 50p Is=3D. 04p mfg=3DFairchild Vds=3D60 Ron=3D2 Qg=3D1.5n)

I hope I've posted the right .asc file this time. The net list does include the LT3050 which suggests I've probably got it right.

-- Bill Sloman, Nijmegen