Increasing EL inverter drive power

The "squeal" from these inexpensive off-the-shelf EL wire/tape inverters you can buy for Halloween costumes and stuff is revolting!

I have one on the bench driving a five foot section of EL wire from the recommended 12VDC supply and in a quiet house I can hear it whining 30 feet away. irritating high-pitch racket

Has nobody figured out how to make an inexpensive inverter for this stuff that's shushie?

In my experimenting with EL panels, years ago, I found they're sensitive to the operating frequency. I don't think you can make major changes, such as going above 20kHz, and have them still work OK.

Nope, seems unlikely. 800-2kHz is problematic though because it's around the area where the human ear equal loudness curve bottoms out, even small amounts of whine is easily heard in a quiet room and objectionable. Do you know what causes the whine...magnetostriction in the transformer?

Unfortunately the circuit I posted in the link seems relatively insensitive on operating frequency with respect to component values other than the transformer or supply voltage perhaps it was designed that way. Only way I found to increase the brightness of the small EL sheet it's driving is to increase the input voltage which also increases the whine. Designed to be quiet with the properties of the original load I guess, well doesn't help me much cuz the original part is long gone.

It would be nice to run several lengths on something like a 4192A LF impedance analyzer to see what kind of load they present with respect to frequency, unfortunately still don't have one of those. an impedance analyzer/VNA is next on my to-buy list.

It's too bad, when this type of tape is driven by a driver with more oomph to it and higher frequency the glow it emits is very pleasing:

It comes out a bit brighter and white-er in the pic than it really is. If not for the fading and drive issues i'd prefer it for LCD backlighting vs the white LEDs cheap LCD displays use for backlighting now which I find really harsh and eye-strain inducing

Not only that, they fade over time, some get spots, they are all faint and in general give miserable "service" for the bother. The lighting panel for flat screen monitors, etc on the other hand, are very decent and have a simple, quiet driver.

Why not do the voltage conversion at some suitable ultrasonic frequency, smooth the result and then commutate it with a MOSFET bridge at the frequency that the EL device likes?

John

Yeah, if I were going to build my own EL driver board that's how I'd do it. I wouldn't try to do the drive circuitry with discretes there's off the shelf stuff available for that pretty cheap:

Drive that with a boost converter off 5-12 volts, say, boost to ~50, that controller has some active noise-reduction system (the EL material itself emits much of the noise I've read), it would probably drive 20 feet of half-inch wide EL tape OK.

I think some mfgrs still use EL material in battery-powered devices that must have very long battery life, it can be much more efficient than LED back-lighting. 2mA is plenty to backlight a multimeter screen, say, so you can see it in the dark. But OLED display efficiency may be comparable now