Are the CCFL supplies flybacks or Royers or something? What sorts of open-circuit voltages do they make?
But right, it's all LEDs now.
I like ISDN transformers, but they will be gone too.
The little DRQ-type dual inductors are great. The autotransformer flyback and CW multiplier thing is cool.
-- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
On Sat, 18 Jul 2020 08:19:38 -0700, snipped-for-privacy@highlandsniptechnology.com wrote:
Your fence is now white-washed.
The circuit is incomplete energy transfer (and so may be pretty noisy).
Version 4 SHEET 1 2884 916 WIRE 1296 -352 1248 -352 WIRE 1328 -352 1296 -352 WIRE 1472 -352 1392 -352 WIRE 1648 -352 1536 -352 WIRE 1728 -352 1648 -352 WIRE 1808 -352 1728 -352 WIRE 1248 -336 1248 -352 WIRE 1808 -336 1808 -352 WIRE 448 -320 416 -320 WIRE 576 -320 448 -320 WIRE 704 -320 576 -320 WIRE 832 -320 704 -320 WIRE 960 -320 832 -320 WIRE 1072 -320 960 -320 WIRE 1648 -320 1648 -352 WIRE 448 -288 448 -320 WIRE 576 -288 576 -320 WIRE 704 -288 704 -320 WIRE 832 -288 832 -320 WIRE 960 -288 960 -320 WIRE 1072 -288 1072 -320 WIRE 1808 -256 1808 -272 WIRE 1248 -240 1248 -256 WIRE 1648 -224 1648 -240 WIRE 0 -208 -96 -208 WIRE 144 -208 64 -208 WIRE 1296 -192 1248 -192 WIRE 1328 -192 1296 -192 WIRE 1472 -192 1392 -192 WIRE 1648 -192 1536 -192 WIRE 1728 -192 1648 -192 WIRE 1808 -192 1728 -192 WIRE 448 -176 448 -208 WIRE 576 -176 576 -208 WIRE 704 -176 704 -208 WIRE 832 -176 832 -208 WIRE 960 -176 960 -208 WIRE 1072 -176 1072 -208 WIRE 1248 -176 1248 -192 WIRE 1808 -176 1808 -192 WIRE 1648 -160 1648 -192 WIRE -96 -112 -96 -208 WIRE -16 -112 -96 -112 WIRE 144 -112 144 -208 WIRE 144 -112 64 -112 WIRE 368 -112 144 -112 WIRE 416 -112 416 -320 WIRE 416 -112 368 -112 WIRE 1808 -96 1808 -112 WIRE 448 -80 448 -96 WIRE 576 -80 576 -96 WIRE 576 -80 448 -80 WIRE 704 -80 704 -96 WIRE 704 -80 576 -80 WIRE 784 -80 704 -80 WIRE 832 -80 832 -96 WIRE 832 -80 784 -80 WIRE 960 -80 960 -96 WIRE 960 -80 832 -80 WIRE 1072 -80 1072 -96 WIRE 1072 -80 960 -80 WIRE 1248 -80 1248 -96 WIRE 416 -64 416 -112 WIRE 1648 -64 1648 -80 WIRE -96 -48 -96 -112 WIRE 144 -48 144 -112 WIRE 1296 -32 1248 -32 WIRE 1328 -32 1296 -32 WIRE 1472 -32 1392 -32 WIRE 1648 -32 1536 -32 WIRE 1728 -32 1648 -32 WIRE 1808 -32 1728 -32 WIRE 1248 -16 1248 -32 WIRE 1808 -16 1808 -32 WIRE 1648 0 1648 -32 WIRE -96 64 -96 32 WIRE -16 64 -96 64 WIRE 144 64 144 32 WIRE 144 64 48 64 WIRE 208 64 144 64 WIRE 256 64 208 64 WIRE 416 64 416 16 WIRE 480 64 416 64 WIRE 672 64 544 64 WIRE 736 64 672 64 WIRE 784 64 784 -80 WIRE 784 64 736 64 WIRE 816 64 784 64 WIRE 976 64 880 64 WIRE 1088 64 976 64 WIRE 1808 64 1808 48 WIRE 1248 80 1248 64 WIRE 1648 96 1648 80 WIRE -96 112 -96 64 WIRE 672 112 672 64 WIRE 1296 128 1248 128 WIRE 1328 128 1296 128 WIRE 1472 128 1392 128 WIRE 1648 128 1536 128 WIRE 1728 128 1648 128 WIRE 1808 128 1728 128 WIRE 144 144 144 64 WIRE 1088 144 1088 64 WIRE 1248 144 1248 128 WIRE 1808 144 1808 128 WIRE 1648 160 1648 128 WIRE 576 192 272 192 WIRE 624 192 576 192 WIRE 976 208 976 64 WIRE 1808 224 1808 208 WIRE 1088 240 1088 208 WIRE 1248 240 1248 224 WIRE -48 256 -96 256 WIRE 16 256 -48 256 WIRE 400 256 272 256 WIRE 576 256 480 256 WIRE 672 256 672 208 WIRE 672 256 576 256 WIRE 1648 256 1648 240 WIRE 672 288 672 256 WIRE 1296 288 1248 288 WIRE 1328 288 1296 288 WIRE 1472 288 1392 288 WIRE 1648 288 1536 288 WIRE 1728 288 1648 288 WIRE 1808 288 1728 288 WIRE -96 304 -96 256 WIRE 1248 304 1248 288 WIRE 1808 304 1808 288 WIRE 352 320 272 320 WIRE 1648 320 1648 288 WIRE 1808 384 1808 368 WIRE 672 400 672 368 WIRE 1248 400 1248 384 WIRE 1648 416 1648 400 WIRE -96 448 -96 368 WIRE -16 448 -96 448 WIRE 144 448 144 368 WIRE 144 448 64 448 WIRE 208 448 144 448 WIRE 352 448 352 320 WIRE 352 448 288 448 WIRE 480 448 352 448 WIRE 976 448 976 288 WIRE 976 448 480 448 WIRE 1296 448 1248 448 WIRE 1328 448 1296 448 WIRE 1472 448 1392 448 WIRE 1648 448 1536 448 WIRE 1728 448 1648 448 WIRE 1808 448 1728 448 WIRE 1248 464 1248 448 WIRE 1808 464 1808 448 WIRE 144 480 144 448 WIRE 1648 480 1648 448 WIRE 1808 544 1808 528 WIRE 1248 560 1248 544 WIRE 1648 576 1648 560 WIRE 608 592 608 512 FLAG 144 480 0 FLAG 672 400 0 FLAG 1728 -352 HV1 FLAG 368 -112 IN FLAG -96 112 0 FLAG 736 64 DRAIN FLAG 576 192 GATE FLAG 576 256 SRC FLAG 480 448 FB FLAG 1248 -240 0 FLAG -48 256 COMP FLAG 208 64 +9V FLAG 1808 -256 0 FLAG 1296 -352 Z FLAG 1648 -224 0 FLAG 1088 240 0 FLAG 1728 -192 HV2 FLAG 1248 -80 0 FLAG 1808 -96 0 FLAG 1296 -192 Z FLAG 1648 -64 0 FLAG 1728 -32 HV3 FLAG 1248 80 0 FLAG 1808 64 0 FLAG 1296 -32 Z FLAG 1648 96 0 FLAG 1728 128 HV4 FLAG 1248 240 0 FLAG 1808 224 0 FLAG 1296 128 Z FLAG 1648 256 0 FLAG 1728 288 HV5 FLAG 1248 400 0 FLAG 1808 384 0 FLAG 1296 288 Z FLAG 1648 416 0 FLAG 1728 448 HV6 FLAG 1248 560 0 FLAG 1808 544 0 FLAG 1296 448 Z FLAG 1648 576 0 SYMBOL PowerProducts\\LTC3803 144 256 R0 SYMATTR InstName U1 SYMBOL ind2 432 -304 R0 WINDOW 0 91 29 Right 2 WINDOW 3 113 63 Right 2 SYMATTR InstName L1
SYMATTR Type ind SYMATTR SpiceLine Ipk=3.0 Rser=0.32 Cpar=1pF SYMBOL ind2 1264 -240 R180 WINDOW 0 101 76 Right 2 WINDOW 3 102 38 Right 2 SYMATTR InstName L2
SYMATTR Type ind SYMATTR SpiceLine Ipk=20 Rser=0.32 Cpar=2pF SYMBOL nmos 624 112 R0 WINDOW 0 119 67 Left 2 WINDOW 3 88 102 Left 2 SYMATTR InstName Q1 SYMATTR Value Si9420DY SYMBOL res 656 272 R0 WINDOW 0 67 34 Left 2 WINDOW 3 60 67 Left 2 SYMATTR InstName R1 SYMATTR Value 0.33 SYMBOL res 128 -64 R0 WINDOW 0 60 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R2 SYMATTR Value 5K SYMBOL res 80 432 R90 WINDOW 0 -8 99 VBottom 2 WINDOW 3 -35 24 VTop 2 SYMATTR InstName R5 SYMATTR Value 50k SYMBOL cap -80 368 R180 WINDOW 0 -52 43 Left 2 WINDOW 3 -56 10 Left 2 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL voltage -96 -64 R0 WINDOW 123 -220 84 Left 2 WINDOW 0 49 44 Left 2 WINDOW 3 49 79 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName Vin SYMATTR Value 24 SYMBOL res -32 -96 R270 WINDOW 0 -39 62 VTop 2 WINDOW 3 -46 61 VBottom 2 SYMATTR InstName Rin SYMATTR Value 1m SYMBOL cap 64 -224 R90 WINDOW 0 69 61 VBottom 2 WINDOW 3 41 8 VTop 2 SYMATTR InstName C4 SYMATTR Value 1 SYMBOL schottky 1328 -336 R270 WINDOW 0 46 35 VTop 2 WINDOW 3 -15 40 VBottom 2 SYMATTR InstName D2 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL res 496 240 R90 WINDOW 0 68 52 VBottom 2 WINDOW 3 75 53 VTop 2 SYMATTR InstName R7 SYMATTR Value 2K SYMBOL cap 48 48 R90 WINDOW 0 60 70 VBottom 2 WINDOW 3 34 -1 VTop 2 SYMATTR InstName C11
SYMBOL schottky 1472 -336 R270 WINDOW 0 45 32 VTop 2 WINDOW 3 -14 38 VBottom 2 SYMATTR InstName D1 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1792 -336 R0 WINDOW 0 55 17 Left 2 WINDOW 3 55 52 Left 2 SYMATTR InstName C6 SYMATTR Value 47n SYMBOL cap 544 48 R90 WINDOW 0 -49 28 VBottom 2 WINDOW 3 -38 26 VTop 2 SYMATTR InstName C7 SYMATTR Value 5n SYMBOL res 400 -80 R0 WINDOW 0 -69 49 Left 2 WINDOW 3 -67 85 Left 2 SYMATTR InstName R10 SYMATTR Value 250 SYMBOL res 1632 -336 R0 WINDOW 0 62 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R3 SYMATTR Value 8e6 SYMBOL schottky 816 80 R270 WINDOW 0 -39 35 VTop 2 WINDOW 3 -45 35 VBottom 2 SYMATTR InstName D3 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1072 144 R0 WINDOW 0 -42 29 Left 2 WINDOW 3 -50 -14 Left 2 SYMATTR InstName C1 SYMATTR Value 50n SYMBOL res 960 192 R0 WINDOW 0 -67 38 Left 2 WINDOW 3 -75 75 Left 2 SYMATTR InstName R4 SYMATTR Value 7.6K SYMBOL res 304 432 R90 WINDOW 0 -9 95 VBottom 2 WINDOW 3 -36 21 VTop 2 SYMATTR InstName R6 SYMATTR Value 100 SYMBOL ind2 560 -304 R0 WINDOW 0 91 29 Right 2 WINDOW 3 113 63 Right 2 SYMATTR InstName L3
SYMATTR Type ind SYMATTR SpiceLine Ipk=3.0 Rser=0.32 Cpar=1pF SYMBOL ind2 688 -304 R0 WINDOW 0 91 29 Right 2 WINDOW 3 113 63 Right 2 SYMATTR InstName L4
SYMATTR Type ind SYMATTR SpiceLine Ipk=3.0 Rser=0.32 Cpar=1pF SYMBOL ind2 816 -304 R0 WINDOW 0 91 29 Right 2 WINDOW 3 113 63 Right 2 SYMATTR InstName L5
SYMATTR Type ind SYMATTR SpiceLine Ipk=3.0 Rser=0.32 Cpar=1pF SYMBOL ind2 944 -304 R0 WINDOW 0 91 29 Right 2 WINDOW 3 113 63 Right 2 SYMATTR InstName L6
SYMATTR Type ind SYMATTR SpiceLine Ipk=3.0 Rser=0.32 Cpar=1pF SYMBOL ind2 1056 -304 R0 WINDOW 0 91 29 Right 2 WINDOW 3 113 63 Right 2 SYMATTR InstName L7
SYMATTR Type ind SYMATTR SpiceLine Ipk=3.0 Rser=0.32 Cpar=1pF SYMBOL ind2 1264 -80 R180 WINDOW 0 101 76 Right 2 WINDOW 3 102 38 Right 2 SYMATTR InstName L8
SYMATTR Type ind SYMATTR SpiceLine Ipk=20 Rser=0.32 Cpar=2pF SYMBOL schottky 1328 -176 R270 WINDOW 0 46 35 VTop 2 WINDOW 3 -15 40 VBottom 2 SYMATTR InstName D4 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 1472 -176 R270 WINDOW 0 45 32 VTop 2 WINDOW 3 -14 38 VBottom 2 SYMATTR InstName D5 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1792 -176 R0 WINDOW 0 55 17 Left 2 WINDOW 3 55 52 Left 2 SYMATTR InstName C3 SYMATTR Value 47n SYMBOL res 1632 -176 R0 WINDOW 0 62 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R8 SYMATTR Value 8e6 SYMBOL ind2 1264 80 R180 WINDOW 0 101 76 Right 2 WINDOW 3 102 38 Right 2 SYMATTR InstName L9
SYMATTR Type ind SYMATTR SpiceLine Ipk=20 Rser=0.32 Cpar=2pF SYMBOL schottky 1328 -16 R270 WINDOW 0 46 35 VTop 2 WINDOW 3 -15 40 VBottom 2 SYMATTR InstName D6 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 1472 -16 R270 WINDOW 0 45 32 VTop 2 WINDOW 3 -14 38 VBottom 2 SYMATTR InstName D7 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1792 -16 R0 WINDOW 0 55 17 Left 2 WINDOW 3 55 52 Left 2 SYMATTR InstName C5 SYMATTR Value 47n SYMBOL res 1632 -16 R0 WINDOW 0 62 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R9 SYMATTR Value 8e6 SYMBOL ind2 1264 240 R180 WINDOW 0 101 76 Right 2 WINDOW 3 102 38 Right 2 SYMATTR InstName L10
SYMATTR Type ind SYMATTR SpiceLine Ipk=20 Rser=0.32 Cpar=2pF SYMBOL schottky 1328 144 R270 WINDOW 0 46 35 VTop 2 WINDOW 3 -15 40 VBottom 2 SYMATTR InstName D8 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 1472 144 R270 WINDOW 0 45 32 VTop 2 WINDOW 3 -14 38 VBottom 2 SYMATTR InstName D9 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1792 144 R0 WINDOW 0 55 17 Left 2 WINDOW 3 55 52 Left 2 SYMATTR InstName C8 SYMATTR Value 47n SYMBOL res 1632 144 R0 WINDOW 0 62 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R11 SYMATTR Value 8e6 SYMBOL ind2 1264 400 R180 WINDOW 0 101 76 Right 2 WINDOW 3 102 38 Right 2 SYMATTR InstName L11
SYMATTR Type ind SYMATTR SpiceLine Ipk=20 Rser=0.32 Cpar=2pF SYMBOL schottky 1328 304 R270 WINDOW 0 46 35 VTop 2 WINDOW 3 -15 40 VBottom 2 SYMATTR InstName D10 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 1472 304 R270 WINDOW 0 45 32 VTop 2 WINDOW 3 -14 38 VBottom 2 SYMATTR InstName D11 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1792 304 R0 WINDOW 0 55 17 Left 2 WINDOW 3 55 52 Left 2 SYMATTR InstName C9 SYMATTR Value 47n SYMBOL res 1632 304 R0 WINDOW 0 62 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R12 SYMATTR Value 8e6 SYMBOL ind2 1264 560 R180 WINDOW 0 101 76 Right 2 WINDOW 3 102 38 Right 2 SYMATTR InstName L12
SYMATTR Type ind SYMATTR SpiceLine Ipk=20 Rser=0.32 Cpar=2pF SYMBOL schottky 1328 464 R270 WINDOW 0 46 35 VTop 2 WINDOW 3 -15 40 VBottom 2 SYMATTR InstName D12 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 1472 464 R270 WINDOW 0 45 32 VTop 2 WINDOW 3 -14 38 VBottom 2 SYMATTR InstName D13 SYMATTR Value BAT46WJ SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 1792 464 R0 WINDOW 0 55 17 Left 2 WINDOW 3 55 52 Left 2 SYMATTR InstName C10 SYMATTR Value 47n SYMBOL res 1632 464 R0 WINDOW 0 62 21 Left 2 WINDOW 3 60 56 Left 2 SYMATTR InstName R13 SYMATTR Value 8e6 SYMBOL res 432 -192 R0 SYMATTR InstName R14 SYMATTR Value .1 SYMBOL res 560 -192 R0 SYMATTR InstName R15 SYMATTR Value .1 SYMBOL res 688 -192 R0 SYMATTR InstName R16 SYMATTR Value .1 SYMBOL res 816 -192 R0 SYMATTR InstName R17 SYMATTR Value .1 SYMBOL res 944 -192 R0 SYMATTR InstName R18 SYMATTR Value .1 SYMBOL res 1056 -192 R0 SYMATTR InstName R19 SYMATTR Value .1 TEXT 504 -368 Bottom 2 !K1 L1 L2 0.98 TEXT -64 592 Left 2 !.tran 100m startup TEXT 248 -304 Left 2 ;8X Q4436-BL TEXT 376 424 Left 2 ;0.8V TEXT 712 248 Left 2 ;ZVN4424 TEXT -64 552 Left 2 !.options reltol = 0.01 TEXT 264 -264 Left 2 ;Lp = 22 uH TEXT 280 -224 Left 2 ;1:5 TEXT 1504 -264 Left 2 ;200 uA TEXT -72 -320 Left 2 ;200V Octal Flyback Supply TEXT -48 -272 Left 2 ;J Larkin Jul 17 2020 TEXT 1312 616 Left 2 ;===== 6 of 8 isolated channels ===== TEXT -56 632 Left 2 ;use alternate solver TEXT 1400 -264 Left 2 ;BAV23S TEXT 1504 -104 Left 2 ;200 uA TEXT 1400 -104 Left 2 ;BAV23S TEXT 1504 56 Left 2 ;200 uA TEXT 1400 56 Left 2 ;BAV23S TEXT 1504 216 Left 2 ;200 uA TEXT 1400 216 Left 2 ;BAV23S TEXT 1504 376 Left 2 ;200 uA TEXT 1400 376 Left 2 ;BAV23S TEXT 1504 536 Left 2 ;200 uA TEXT 1400 536 Left 2 ;BAV23S TEXT 448 -352 Left 2 !K2 L3 L8 0.98 TEXT 704 -376 Left 2 !K3 L4 L9 0.98 TEXT 696 -352 Left 2 !K4 L5 L10 0.98 TEXT 952 -368 Left 2 !K5 L6 L11 0.98 TEXT 952 -344 Left 2 !K6 L7 L12 0.98
The ones I've used have been Royers, with open-circuit outputs over a kilovolt (so they can strike the discharge).
They come with two HV caps on the output that you can use to make voltage doublers, which is convenient.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
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It's probably Baxandall Class-D oscillator. Jim Williams seems to have got the circuit from England without getting the literature reference that shou ld have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
From my web-site.
"The circuit is probably best known from Jim Williams? series of ap plication notes for Linear Technology, on high frequency inverters for driv ing cold cathode back-lights used in laptop computers (application notes AN
45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inverter described by Bright, Pittman and George H. Royer in 1954 in a paper ? ??Transistors as on-off switches in saturable core circuits? in Electrical Manufacturing."The Baxandall inverter is handy for driving high-turns ratio step-up transf ormers which tend end up with rather low self-resonant frequencies.
The Cockroft-Walton multiplier isn't all that cool.
Or you could learn how to design your own special purpose transformers and find a shop that would wind them for you - it isn't all that difficult.
There are lots of variables to twiddle in a transformer design, so getting something close enough off the shelf isn't easy, even if you get downright sloppy about "close enough".
-- Bill Sloman, Sydney
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t the circuit from England without getting the literature reference that sh ould have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
application notes for Linear Technology, on high frequency inverters for dr iving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant invert er described by Bright, Pittman and George H. Royer in 1954 in a paper ?Transistors as on-off switches in saturable core circuits? in Electrical Manufacturing."
sformers which tend end up with rather low self-resonant frequencies.
d find a shop that would wind them for you - it isn't all that difficult.
g something close enough off the shelf isn't easy, even if you get downrigh t sloppy about "close enough".
you are kidding right? a few 100mW at 150V for a low volume product and you want to spend what would quickly be weeks designing/ordering/twiddling a tr ansformer design?
I don't understand that one.
That's about what I expected. Different primary inductances don't change the final DC voltages, and a bit of leakage inductance doesn't matter either.
Sure runs slow! Efficiency is about 3%, not surprising. Just R2 dissipates more power than the loads.
The DC supply current is only about 40 mA, not enough to care about. My pulse rate will be very low too.
-- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
He has huge enthusiasm for designing custom magnetics. I have huge enthusiasm for ordering stock parts from Coilcraft or Digikey and shipping products. He might learn to design with standard parts - it isn't all that difficult.
I wonder how his super oscillator is coming along. He ordered a custom transformer for that, a decade or two ago.
My customer wants a proof-of-principle 150-volt pulser next week, and I have a 10-layer PCB to release first. Really, he should just trust us and order the real things.
-- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
You are barely touching the volt-second capability of those transformers, clearly over-engineered :>
But seriously, what's the inter-winding capacitance and is that tolerable in your app?
piglet
[...]
Yes, and they have limits in terms of voltage.
I also love dual-winding coils. Just make sure to vet the isolation voltage with the manufacturer.
They can generate 1200V or more but I never used them that high. I either drive them with an externally driven Royer (from logic on my board) or drive them directly from a gate driver.
Mine came bare-bones, no caps. The first one I designed dutifully had warnings in English and Spanish. Sure enough the first one it bit was myself (German-born) and the Chinese-born engineer at my client laughed. "See? You should have had that warning on the board also in German and Chinese so we are all protected".
-- Regards, Joerg http://www.analogconsultants.com/
. . . at least I didn't pay you to do it ;-] ( Twain- Sawyer / Finn )
RL
With an even number of identical parts, driven synchronously, it should be possible to reconfigure outputs without altering function and ground ground appropriate points to get an approximate null of local noise current.
Finnicky.
RL
I share his enthusiasm. If you depend on some non-linearities, there is no other way but to learn the craft.
But why can't you have the best of both worlds and use standard parts wherever possible and custom ones when there is a potential for blowing the competition out of the water? Custom parts are still manufacturable, just more expensive.
Best regards, Piotr
Sure I use custom magnetics. I've posted lots of examples here. But
98% of the time, you can use standard parts, available in quantity, cheap, overnight delivery. Or better yet, use the ones downstairs in the stockroom.Custom or home-made is generally needed for transmission-line transformers, big power transformers, a few things like that. Maybe flybacks, but if you are clever there are lots of ways to use standard parts.
I've probably designed 20x as many transformers and inductors as Sloman. Here are just a few:
I sometimes design my own resistors and coaxial cables too. When I have to.
-- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
On Monday, July 20, 2020 at 1:49:21 AM UTC+10, Lasse Langwadt Christensen w rote:
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ut the
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got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
f application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application note s AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inve rter described by Bright, Pittman and George H. Royer in 1954 in a paper ?Transistors as on-off switches in saturable core circuits? in Electrical Manufacturing."
ansformers which tend end up with rather low self-resonant frequencies.
and find a shop that would wind them for you - it isn't all that difficult.
ing something close enough off the shelf isn't easy, even if you get downri ght sloppy about "close enough".
ou
transformer design?
It might take John Larkin weeks. The design is obvious - I could knock up s omething now, if I felt like it. I've already dealt with the problem that s truck me as salient - finding a coil former with enough pins (see earlier p ost).
Finding a transformer winder took me a day or so when I was in Nijmegen. Th ey were in Horst, which was a twenty minute drive away.
John Larkin works in San Francisco, which is a larger town.
-- Bill Sloman, Sydney
1 mA
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y first
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got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
of application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application not es AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inv erter described by Bright, Pittman and George H. Royer in 1954 in a paper ?Transistors as on-off switches in saturable core circuits? ? in Electrical Manufacturing."
ransformers which tend end up with rather low self-resonant frequencies.
and find a shop that would wind them for you - it isn't all that difficult .
ting something close enough off the shelf isn't easy, even if you get downr ight sloppy about "close enough".
you
transformer design?
isn't a standard part? Fairly obviously stocked by a major distributor ...
Which confirmed that even a well-gapped core had enough hysteresis to gener ate harmonics - 95dB below the fundamental. I went over to a variant of the Wien bridge. If I ever find a customer I'll build one.
John Larkin does like it when his customers trust him. He can slap together something for them really quickly. And why is a ten layer PCB supposed to be impressive? The chaotic design process that left him needing that many l ayers would be.
-- Bill Sloman, Sydney
Very intellectually demanding design.
I couldn't be bothered finding out if the rest were equally impressive.
If you count that as "design" you can see why John Larkin thinks he designs electronics. Five turns - one design. Six turns - a second design. The fluency is amazing.
-- Bill Sloman, Sydney
mA
geSize=25
lyback
.first
ut the
etter
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e got the circuit from England without getting the literature reference tha t should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
of application notes for Linear Technology, on high frequency inverters fo r driving cold cathode back-lights used in laptop computers (application no tes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverte r as a current driven Royer inverter, referring back to the non-resonant in verter described by Bright, Pittman and George H. Royer in 1954 in a pape r ?Transistors as on-off switches in saturable core circuits? ? in Electrical Manufacturing."
transformers which tend end up with rather low self-resonant frequencies.
s and find a shop that would wind them for you - it isn't all that difficul t.
tting something close enough off the shelf isn't easy, even if you get down right sloppy about "close enough".
d you
a transformer design?
He wouldn't know. He buys in his transformers, and all he knows is whether the circuit works.
You are probably better off thinking in terms of the self-resonant frequenc y of the transformer (from which you can extract a capacitance).
The problem with step-up transformers is lots of turns on the secondary, wh ich means high inductance and a low self-resonant frequency, which make dri ving them fast difficult.
Baxandall seems to have invented his class-D inverter to deal with this, th ough the paper doesn't mention it - I worked for a guy who done his apprent iceship with Baxandall, and that story came from him.
-- Bill Sloman, Sydney
On Fri, 17 Jul 2020 09:49:16 -0700, snipped-for-privacy@highlandsniptechnology.com wrote:
Here is the companion micropower 150-volt regulator.
I'll probably include a voltage-set trimpot, for a couple of reasons.
Version 4 SHEET 1 1052 680 WIRE -400 -176 -480 -176 WIRE -352 -176 -400 -176 WIRE -160 -176 -272 -176 WIRE 16 -176 -64 -176 WIRE 160 -176 96 -176 WIRE 256 -176 160 -176 WIRE 352 -176 256 -176 WIRE 352 -112 352 -176 WIRE -480 -80 -480 -176 WIRE -80 -48 -80 -128 WIRE 16 -48 -80 -48 WIRE 160 -48 160 -176 WIRE 160 -48 96 -48 WIRE 160 -16 160 -48 WIRE 352 0 352 -48 WIRE -480 32 -480 0 WIRE -80 48 -80 -48 WIRE 160 96 160 64 WIRE 160 96 -16 96 WIRE 160 160 160 96 WIRE -80 192 -80 144 WIRE -80 304 -80 256 WIRE 160 304 160 240 FLAG 160 304 0 FLAG -480 32 0 FLAG -80 304 0 FLAG 352 0 0 FLAG -400 -176 Vin FLAG 256 -176 Vreg SYMBOL nmos -160 -128 R270 WINDOW 0 -9 -48 VRight 2 WINDOW 3 -41 -75 VRight 2 SYMATTR InstName M1 SYMATTR Value LND250 SYMBOL res 144 144 R0 WINDOW 0 -67 39 Left 2 WINDOW 3 -86 73 Left 2 SYMATTR InstName R1 SYMATTR Value 450k SYMBOL voltage -480 -96 R0 WINDOW 0 60 70 Left 2 WINDOW 3 32 109 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value PULSE(0 200 1m 20m 0 1) SYMBOL res 112 -64 R90 WINDOW 0 74 56 VBottom 2 WINDOW 3 82 57 VTop 2 SYMATTR InstName R3 SYMATTR Value 100K SYMBOL npn -16 48 M0 WINDOW 0 107 21 Left 2 WINDOW 3 82 53 Left 2 SYMATTR InstName Q1 SYMATTR Value 2N5550 SYMBOL res 144 -32 R0 WINDOW 0 66 35 Left 2 WINDOW 3 63 69 Left 2 SYMATTR InstName R4 SYMATTR Value 5e6 SYMBOL cap 336 -112 R0 WINDOW 0 -53 23 Left 2 WINDOW 3 -56 56 Left 2 SYMATTR InstName C1 SYMATTR Value 50n SYMBOL zener -64 256 R180 WINDOW 0 69 41 Left 2 WINDOW 3 56 6 Left 2 SYMATTR InstName D1 SYMATTR Value BZX84B12VL SYMBOL res -368 -160 R270 WINDOW 0 -35 56 VTop 2 WINDOW 3 -41 56 VBottom 2 SYMATTR InstName R2 SYMATTR Value 1 SYMBOL res 0 -160 R270 WINDOW 0 -35 56 VTop 2 WINDOW 3 -41 56 VBottom 2 SYMATTR InstName R5 SYMATTR Value 20K TEXT -462 216 Left 2 !.tran 250m TEXT -480 128 Left 2 ;150V Regulator TEXT -480 176 Left 2 ;JL Jul 19 2020 TEXT -184 136 Left 2 ;FCX458 TEXT -216 288 Left 2 ;MAZ3120 TEXT 232 112 Left 2 !.MODEL LND250 NMOS (LEVEL=3 RS=150.00 NSUB=5.0E13 \n+DELTA=0.1 KAPPA=1.O TPG=1 CGDO=2.1716E-12 \n+RD=40.0 VTO=-2.0 VMAX=1.0E8 ETA=0.1 \n+NFS=6.6E10 TOX=1.0E-7 LD=1.698E-9 UO=862.425\n+XJ=6.4666E-7 THETA=1.0E-5 CGSO=5.09E-10 L=10.0E-6\n+W=600E-6) \n.ENDS
-- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
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t the circuit from England without getting the literature reference that sh ould have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
application notes for Linear Technology, on high frequency inverters for dr iving cold cathode back-lights used in laptop computers (application notes AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant invert er described by Bright, Pittman and George H. Royer in 1954 in a paper ? ??Transistors as on-off switches in saturable core circuits? in Electrical Manufacturing."
sformers which tend end up with rather low self-resonant frequencies.
d find a shop that would wind them for you - it isn't all that difficult.
g something close enough off the shelf isn't easy, even if you get downrigh t sloppy about "close enough".
Isn?t it more that Baxandall copyed and minimally improved on the 1
954 Royer converter?About the Baxandall, has anyone ever used it for commercial product, or is it like for example the Cuk converter and other ?Novel? PhD topologies that is really only good on paper?
I agree that custom magnetics rules. For a volume above 50k you gain a comp etitive advantage that designs using ready made components fails to have. I n my career I have only used ready made for a converter a couple of times ( not counting buck converters)
Cheers
Klaus
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got the circuit from England without getting the literature reference that should have come with it - Baxandall, P.J, Proc I.E.E 106, B, 748 (1959.
f application notes for Linear Technology, on high frequency inverters for driving cold cathode back-lights used in laptop computers (application note s AN45, AN49, AN51, AN55, AN61, AN65). Jim Williams describes the inverter as a current driven Royer inverter, referring back to the non-resonant inve rter described by Bright, Pittman and George H. Royer in 1954 in a paper ?Transistors as on-off switches in saturable core circuits? in Electrical Manufacturing."
ansformers which tend end up with rather low self-resonant frequencies.
and find a shop that would wind them for you - it isn't all that difficult.
ing something close enough off the shelf isn't easy, even if you get downri ght sloppy about "close enough".
The story I heard was that the Linear Technology reps in the UK were asking after high-voltage inverters and got the circuit diagram for a Baxandall c lass-D oscillator based device.
1954 Royer converter?Probably not. He was working in the UK and the Royer paper was in a US trad e publication - it doesn't show up in the literature cited in his paper.
The inductor on the centre-tap is major difference from the Royer inverter, and produces very different behavior.
s it like for example the Cuk converter and other ?Novel? P hD topologies that is really only good on paper?
The link to the Linear Technology application notes AN45, AN49, AN51, AN55, AN61, AN65 answers that question. Laptops with cold-cathode back lighting used it in droves.
I've put it into two products. The GaAs crystal-puller that was making 95% of the single-crystal GaAs crystals in the west in the late 1980's isn't a mass market item, but it got retrofitted with my variation after 1987. It s eemed to work rather better than the original oscillator (which had used pa rts that had gone obsolete by then).
mpetitive advantage that designs using ready made components fails to have. In my career I have only used ready made for a converter a couple of times (not counting buck converters)
I mostly worked on stuff that sold at the 10 to 100 per year level - the Ga As crystal puller was on the low end of that. If you need the performance c ustom magnetics can sometimes be the only way to get it.
-- Bill Sloman, Sydney
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