Isolated 3.3V to 5V 100mA design
Isolated 3.3V to 5V 100mA design
(OP)
Making a boost circuit is easy....making it 1500V isolated is a little more tricky. Anyone have a favorite circuit they have used?
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Isolated 3.3V to 5V 100mA design
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RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
Have you considered using PCB mounted isolated DC-DC power supplies? The isolation of such an animal (if you can find one for that DC voltage in and DC voltage out) is pretty high.
Taking a quick second look at OperaHouse's post reminded me of a technical paper I downloaded the other day: "fetdrvr-t.pdf" You can do a quick Google search for it and you will find "AN ISOLATED MOSFET GATE DRIVER". The paper shows several similar topologies for creating an isolated power source at a high frequency. For the high voltage isolation, you will probably need to separate the primary from the secondary with dielectric tape.
RE: Isolated 3.3V to 5V 100mA design
TTFN
RE: Isolated 3.3V to 5V 100mA design
Martek Power,
C&D Technologies,
International Power Sources,
Unfortunately, my experience with one of these isolated DC-DC converter solutions resulted in about 100mV of noise riding on my 5V rail.
RE: Isolated 3.3V to 5V 100mA design
But...maybe I will look around. Most DC/DC are not boost but bucks as well
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
TTFN
RE: Isolated 3.3V to 5V 100mA design
"Perhaps the TV was up too high and you miss interpreted" what hrc said the circuit wants/needs :).
hrc wants/needs a circuit that will give 5V @ 100mA out from a 3.3V input source and that will have up to 1500V isolation between input and output.
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
hrc; Find a DC-DC controller chip Maxim et. al. that shows you how to use a transformer on the output. Generally this scheme is used to provide multiple output voltages using only one controller.
Then you use one of the small enclosed torriodal transformer blanks made by Amadon. Essentially they are a fully enclosed bobben, high frequency transformer, that is held together with a single nylon screw thru the center. When the screw is removed the housing splits in half down the center and out comes a little white bobben. The bobben has a divider in the center to keep the windings separate. When you wind one side of the bobben with the primary and the second side of the bobben, (on the other side of the little divider), with your secondary, they have a very high isolation, easily 1500 V.
You can you use this in production or you can take the functioning prototype transformer that you created to many different transformer companies. They'll measure its characteristics and can quote you production on a transformer that will perform identically, but may be an entirely different shape, if you would prefer.
http://www.amidoncorp.com/aai_specifications.htm
This is a complex fedback isolated method generally you wouldn't need isolated feedback you just generate two outputs out of the transformer and monitor the one on the regulator side.
And another option:
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or see the top of figure 2 in here:
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RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
RE: Isolated 3.3V to 5V 100mA design
all for all...not a bad trade off I think
Once again, thanks very much for all the responses.