I've been interested in piezotransformers for some time now. Despite the fact that they have been around for awhile, not many electronics people seem to be familiar with them.
Currently, they are used to generate high voltage for ion air purifiers (ozone), that are supposed to make the air safer to breathe. Interestingly enough, these products aren't sold by reputable sellers and they all come in plain boxes with no mention of the point of origin. So, getting information about how they operate is easier said than done:>:
They are also widely used as CCFL power sources, where the requirements are ~600 VAC at 2 to 6 ma.
They excel at producing high voltage with resistive loads greater than
150 K ohms and up. In fact, they have so much voltage gain when the load impedance is high, that they must be throttled back in order to prevent the output voltage from arcing through the ceramic and shattering them into pieces. Most will produce 2 kilovolts safely however.
Anyway, I was curious whether anyone else knows about these units and/or has designed drivers that work in constant voltage mode rather than constant current (as the TI driver does). The specs for the TI driver can be found at:
The spec sheet has a very nice summary of the piezotransformer operation in addition to chip specs.
The only US vendor that I know of (with standard products listed online) is:
They make multilayer and single layer piezotransformers.
CTS Ceramics claims to make them, but their website has no references to actual part numbers of standard products.
Texas Instruments makes an evaluation kit, complete with piezotransformers and driver chip, but it is not advertised on their website. You have to ask specifically for it. The TI part number for the evaluation kit (EVM) is UCC3976-77EVM. I have a pdf of the technical info in the EVM and will send it to anyone who needs it. I've also posted it in abse.
What say, anyone out there played with them?
Mebart