Thanks Jeroen, Reading Phil's reply reminded me of the discussion in Feynman's book. I maybe need a bit of hand holding as I 'walk' across the gap, and Dick will be the perfect person for that. :^)
George H.
Designing for a start-up is what I am doing right now. Plus some regular consulting work. It's a lot more fun than legal stuff.
[...]
But you only need 20mA. Even some common-mode chokes might be able to handle that. Also, there are some E-E core dual inductors that have a performance that could rival toroids. Plus there's always ye old shield can.
Most PoE transformers are for flybacks, probably because that is the cheapest converter architecture.
-- Regards, Joerg http://www.analogconsultants.com/
Wuerth has the "Trilogy of Magnetics". It's probably good for beginners, around $50. I've got it here because a sales guy dropped it off, but will give it back because I outgrew that a long time ago. All I had in the early 90's when I had to design my 1st mass production switcher was the "Unitrode IC Data Handbook". That got me going in this field. Probably TI still has it online somewhere because they swallowed Unitrode.
-- Regards, Joerg http://www.analogconsultants.com/
they generally spec them both for series and parallel ;)
how about a capacitive coupled boost?
something like this:
-Lasse
Yup, done a few of those myself, they work fine. Only 2W are needed here.
It's going to result in *KABLAM* :-)
But since Phil's stuff is all noise-critical he probably should not use a flyback architecture. Gapped cores spew a lot of EMI around.
-- Regards, Joerg http://www.analogconsultants.com/
Do they make gapped toroids? You could make something with symmetrical gaps one on each side, or maybe a bunch of stripes...(I guess that's hard to make.)
George H.
You'd think so, but no. The ones I'm using (Murata 32331C) aren't called out in the datasheet as anything except a single winding between pins 1 and 3, whereas in reality there's another independent one between pins 2 and 4 (the datasheet is at
It's a possibility, for sure. I normally don't think of capacitive boosters and hundreds of milliwatts at the same time, but it could work OK. It's slightly inconvenient due to having to run off +-15 to get the required output, but not awful.
I already have a buck-boost generating -15V from a +16-20V laptop supply, so if I voltage-doubled that and stacked it on top of the raw
+-15 rails, I'd get there that way as well. I wouldn't have as much control over the supply sequencing that way, but you can't beat the price.Fun stuff.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
You can get pot cores with gaps in the centre post, which are pretty good though not as good as a toroid.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
That's like my "bubble" (boost-doubler) converter that I posted a few days ago, except that I didn't use an integrated switching controller and tweaked some things.
Rob described it as "a sepic without the second winding."
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
[...]
Yup:
But most of the time it's done in powder fashion which results in a "distributed gap". Comes with its own sorts of issues, such as the fact that the resin used as a binder can deteriorate over time. Especially when running them a bit hot.
-- Regards, Joerg http://www.analogconsultants.com/
Bikers would call that a "Bobber SEPIC" :-)
-- Regards, Joerg http://www.analogconsultants.com/
Never mind. I was thinking of a different part--the 32331C has a single two-layer winding, but pins 2 and 4 are also shorted together internally for some reason.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
That could get pretty warm on the girlfriend's feet. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Unless you ride it daredevil-style:
-- Regards, Joerg http://www.analogconsultants.com/
Have you ever posted the input voltage? I haven't found it in the thread. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| 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.
Probably follows the Hobbs house standard, 19V (laptop supply).
-- Regards, Joerg http://www.analogconsultants.com/
On Wednesday, July 17, 2013 6:36:32 PM UTC+2, Phil Hobbs wrote:
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I wouldn't call a capacitive booster, it a normal boost just capacitive cou pled
you can get +/-45V just pick a controller that can handle 45V
hacked together from the lt1071 test fixture:
Version 4 SHEET 1 2808 1492 WIRE 1600 880 1488 880 WIRE 1824 880 1600 880 WIRE 1872 880 1824 880 WIRE 1984 880 1952 880 WIRE 2144 880 1984 880 WIRE 2160 880 2144 880 WIRE 2272 880 2224 880 WIRE 2320 880 2272 880 WIRE 2416 880 2384 880 WIRE 2528 880 2416 880 WIRE 2640 880 2528 880 WIRE 1488 896 1488 880 WIRE 2528 896 2528 880 WIRE 2640 896 2640 880 WIRE 1600 912 1600 880 WIRE 1824 944 1824 880 WIRE 2416 960 2416 880 WIRE 2272 976 2272 944 WIRE 2528 992 2528 960 WIRE 2640 992 2640 976 WIRE 1488 1008 1488 976 WIRE 1600 1008 1600 976 WIRE 1984 1024 1984 880 WIRE 1984 1024 1952 1024 WIRE 2416 1088 2416 1040 WIRE 2416 1088 1952 1088 WIRE 2416 1104 2416 1088 WIRE 1968 1152 1952 1152 WIRE 2064 1152 2048 1152 WIRE 2064 1168 2064 1152 WIRE 2416 1200 2416 1184 WIRE 1824 1248 1824 1232 WIRE 2064 1248 2064 1232 WIRE 2144 1408 2144 880 WIRE 2304 1408 2208 1408 WIRE 2368 1408 2304 1408 WIRE 2544 1408 2432 1408 WIRE 2656 1408 2544 1408 FLAG 2640 880 OUT FLAG 2416 1200 0 FLAG 2528 992 0 FLAG 2640 992 0 FLAG 2064 1248 0 FLAG 1824 1248 0 FLAG 1600 1008 0 FLAG 1488 1008 0 FLAG 1488 880 IN FLAG 2272 976 0 FLAG 2304 1344 0 FLAG 2656 1328 0 FLAG 2544 1344 0 SYMBOL ind 1856 896 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 5 56 VBottom 2 SYMATTR InstName L1 SYMATTR Value 150µ SYMATTR SpiceLine Rser=0.02 Rpar=5000 SYMBOL schottky 2320 896 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D1 SYMATTR Value MBRS360 SYMBOL RES 2400 944 R0 SYMATTR InstName R1 SYMATTR Value 44K SYMBOL RES 2400 1088 R0 SYMATTR InstName R2 SYMATTR Value 1.24K SYMBOL RES 1952 1168 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName R3 SYMATTR Value 1K SYMBOL polcap 2512 896 R0 SYMATTR InstName C1 SYMATTR Value 100µ SYMATTR SpiceLine Rser=15m SYMBOL CAP 2048 1168 R0 SYMATTR InstName C2 SYMATTR Value 1µ SYMBOL VOLTAGE 1488 880 R0 WINDOW 123 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 19 SYMATTR SpiceLine Rser=0.1 SYMBOL polcap 1584 912 R0 SYMATTR InstName C3 SYMATTR Value 100µ SYMBOL PowerProducts\\LT1071HV 1824 1088 R0 SYMATTR InstName U1 SYMBOL res 2624 880 R0 SYMATTR InstName Rload SYMATTR Value 2000 SYMBOL schottky 2288 944 R180 WINDOW 0 24 64 Left 2 WINDOW 3 -27 0 Left 2 SYMATTR InstName D2 SYMATTR Value MBRS360 SYMBOL cap 2224 864 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 1µ SYMATTR SpiceLine V=50 Irms=0 Rser=0.008 Lser=0 mfg="TDK" pn="C
3225X7RlHlO5M" type="X7R" SYMBOL schottky 2432 1392 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D3 SYMATTR Value MBRS360 SYMBOL schottky 2320 1408 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D4 SYMATTR Value MBRS360 SYMBOL polcap 2528 1344 R0 SYMATTR InstName C6 SYMATTR Value 100µ SYMATTR SpiceLine Rser=15m SYMBOL res 2640 1312 R0 SYMATTR InstName Rload1 SYMATTR Value 2000 SYMBOL cap 2208 1392 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 1µ SYMATTR SpiceLine V=50 Irms=0 Rser=0.008 Lser=0 mfg="TDK" pn="C 3225X7RlHlO5M" type="X7R" TEXT 1424 1136 Left 2 !.tran 200m startup-Lasse
Hmm, most of those use a 3 pin mains connector, does that mean they are free from the high voltage high frequency leakage currents that plague modern wall-warts? Do they earth the DC 0V?
-- John Devereux
Bad-Ass Switcher.
-- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Cute! That would nicely fit Larkin's needs... with no significant surge. Somewhat similar to my self-charging CD ignition from the late '60's at Philco-Ford and in the early '70's at Dickson electronics...
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| 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.
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