Hi Joel,
You asked the million dollar question! If you want a few units, you
can get them....but the supply isn't reliable in the US for commercial
purposes. Places that want to design them are selling you design time,
and won't even produce it for you unless you want to buy them by the
ton:>:
I've followed the development of these ever since learning about them
in the 1999, thanks to an article in EDN Magazine. Lots of outfits
claim to make them, but they turn out to be BS claims-they don't
advertise their standard products and there is no real content when
you look for info on their websites. Been there, did that, plenty!
I've even looked in Asia via the web. The Asian suppliers don't even
want to talk to you unless you want to order 200,000 units per year
from them. In general, Asia is a waste of time-take it from someone
who has tried. One Asian vendor tried to hit tried to sell me samples
shipped from .tw, they wanted 12 dollars each unit and $200 for
shipping 3 units. Needless to say, I did not reply:>:
Regarding the roll your own effort.... They are not terribly hard to
make although you will have to attach wires and build a holder to
contain your piezoelement. The supports have to be placed at 1/4 and
3/4 of the physical length or else the movement of the piezoelement
will cause it to fracture. You can't solder wires to them either,
connections must be low mass. If you can deposit silver (very thin,
can't have much mass) on the piezo, anyone in the semiconductor biz
can attach wires for you.
If you want characterized units, you can do it yourself with an HP
network analyzer. I have a Spice model for one that actually works!
The internal parameters are very important with respect to the driver.
All the CCFL inverters on the market today use constant current
regulation, if you want to regulate it with respect to voltage output,
you gotta roll your own driver. This is not impossible, but forget a
single chip solution:>:
I have megabytes and megabytes of info I've collected on them over the
years, there is alot of good ifo on the web too. Keep in mind, some
call them 'piezotransformers' others call them "piezoelectric
transformers" or "piezo transformer" etc. Google turns up lots of
hits....but getting some of the units themselves will be a challenge.
If you want to play with higher powered button or circular devices,
they are available from a European supplier. The circular ones put out
5 times more power than the conventional rectangular Rosen type
devices.
You can buy a development kit from TI that comes with driver chips
(constant current type) and piezotransformers on a PCB. You can also
buy Panasonic units (without a source of specs) from digi-key. Not
cheap, I might add and they are selling them until the stock runs out.
I found a single US supplier that actually has the units in stock for
immediate sale, but they don't even know what a Spice Model
is......again, these are devices without complete specs.
I am working on a photomultiplier supply using one of these units,
hope it will be efficient.
Hey, what are you trying to do with them, and what do you have for
test equipment?? A network analyzer I hope?? Having a network analyzer
will allow you to characterize your own unit, you won't be reliant on
a manufacturer for specs.
In closing, I can say that these devices are appearing in so called
'personal air purifiers'. They generate high voltage, and the sellers
claim breathing ozone is healthy for you:>: The FDA is confiscating
them as fast as they enter the country, but some are on the market
(surplus, ebay and other non-reputable sellers have them). Search for
piezo+air+purifier on ebay, you will have many hits. I haven't looked
inside any of these yet, but they might have a constant voltage driver
although it's probably not regulated well.
So, tell me more...........
Want 20 or 40 mb worth of web info on them?? Ive got a big collection
of files in my personal library. Say the word and I'll ship them via
email.
M
