LED based DC/DC converter
Thomas Magma
seem to Google it down. It was in a SOIC, I think, and it had one LED that
shined on a few to produce a higher voltage (a low current device). Does
anyone know who makes this?...or was this just some crazy dream?
Thomas
John Larkin
You can buy p-v optocouplers that generate something like 9v at
something like 10 uA... handy sometimes. They're an led and an
integrated silicon pv stack, I think. Google "photovoltaic
optocoupler."
John
Spehro Pefhany
Sounds like a photovoltaic optocoupler. It also provides isolation.
For example:
http://www.irf.com/product-info/datasheets/data/pvin.pdf
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Joerg
John and Spehro have already pointed out where to find them.
However, these devices usually do not provide much power. If you just
need a very highly isolated power transfer think along the lines of
contactless chargers and the like. It is possible to transfer power over
several millimeters, through PVC barriers, glass and so on.
Regards, Joerg
Ken Smith
Joerg <notthis...@removethispacbell.net> wrote:
>Hello Thomas,
>
>John and Spehro have already pointed out where to find them.
>
>However, these devices usually do not provide much power. If you just
>need a very highly isolated power transfer think along the lines of
>contactless chargers and the like. It is possible to transfer power over
>several millimeters, through PVC barriers, glass and so on.
You can also do small amounts of power by sending RF through a few pF and
using small Schottky diodes to rectify it. If the logic signal comes from
a CPLD or FPGA, the logic in the device can be changed to AND the signal
with the system clock. Don't expect to get a lot of power this way but it
is cheap.
--
--
kens...@rahul.net forging knowledge
Fred Bloggs
There are app circuits that use an LED to sense ambient light level and
adjust the drive to other LEDs to compensate- brighter when high light
level and dimmer when less light level.
Joerg
> You can also do small amounts of power by sending RF through a few pF and
> using small Schottky diodes to rectify it. If the logic signal comes from
> a CPLD or FPGA, the logic in the device can be changed to AND the signal
> with the system clock. Don't expect to get a lot of power this way but it
> is cheap.
Alternatively you could follow with a diode-capacitor cascade to
multiply. Power isn't going to be that great since many FPGA output
stage FETs won't go much below 30-40 ohms. Other times the allowed
continued load must not be exceeded.
Regards, Joerg
John Larkin
And I've heard of using things called "transformers."
John
Joerg
> And I've heard of using things called "transformers."
They can be awfully small if the frequency is high. But whenever I used
some like that and the time for the design review came people often
stared at those curly thingies on the schematic in disbelief. An analog
part in a digital module? Yeccchh.
Regards, Joerg
John Larkin
Right now, I'm designing a family of VME modules, each with 16
isolated signal conditioning channels. So I need 16 low-noise,
low-cost, zero-footprint floating power supplies. I'm thinking about
using tiny ISDN or similar telecom transformers with sinewave drive.
http://www.filtran.com/filtran/datasheets/7120.pdf
or maybe
http://www.talema.net/en/products/pdf/CFJ_Jul-03.pdf
John
Joerg
> Right now, I'm designing a family of VME modules, each with 16
> isolated signal conditioning channels. So I need 16 low-noise,
> low-cost, zero-footprint floating power supplies. I'm thinking about
> using tiny ISDN or similar telecom transformers with sinewave drive.
>
> http://www.filtran.com/filtran/datasheets/7120.pdf
They also make real quad versions like the LAN transformer TTW6176.
Check Asian mfgs. I don't know what Murata carries in transformers right
now but I have used their CM chokes a lot. Good prices.
Regards, Joerg