Simple Electroluminescent Panel/Wire Driver

Discussion in 'The Projects Forum' started by Melchior, Feb 2, 2008.

  1. Melchior

    Thread Starter New Member

    Feb 2, 2008
    9
    1
    I'm looking for a circuit that could drive ~1 Foot of EL Wire.

    EL Wire is a-bit strange in that it requires high voltage AC at a high frequency to work. Also its acts like a capacitor, FYI.

    It needs to be driven at about 60 Volts 400Hz (although it may work with a lower frequency, it will be dimmer). (Current draw 0.45mA)

    Also just the keep things interesting, I intend to drive it from a single 1.5 V battery.
    Built from as few parts as possible, and no surface mount components.

    Could a blocking type oscillator generate a high enough voltage from 1.5 Volts input? (efficiency would be nice, but not critical)

    Does any one know of any such circuits that could be modified to work in this fashion?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Very interesting!

    The low voltage would be a challenge.

    Is 400Hz the recommended frequency, or is higher frequency acceptable? Reason I'm asking, is I picture an oscillator circuit driving a step-up transformer; a higher frequency would enable the use of a smaller transformer.

    You do not get something for nothing in electronics, or anywhere else. If the boost to 60V@45mA were even close to 100% efficient, it would require around 3A current, which would suck a battery dead fairly quickly. There would be quite a loss just in the semiconductors alone. Typical PN junctions have a voltage drop of 0.6V across them, even at minimal loads. When you're talking AMP loads, the drop goes much higher. MOSFETS have a far lower drop, but would require boost circuits to get voltages high enough to turn their gates on and off.

    Just brainstorming here.
     
  3. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
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  4. Melchior

    Thread Starter New Member

    Feb 2, 2008
    9
    1
    450.0 microampere (µA)

    Thats 27 mW of power.

    According to the specifications; the highest listed frequency is 4000 Hz. (with a corresponding shortened lifetime) -- in fact I'd rather even lower than 400Hz...

    Also I suspect that a true AC sine waveform is likely unneeded, so any kind of AC oscillation would do (sawtooth, square, whatever).

    What types of circuits can generate this level of voltage?
     
  5. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
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    If you would have looked into the links I gave you, you would see how the inner workings of the IC accomplish the task. They basically use a boost converter to power a half-bridge. So, there is a voltage loop for the boost converter with PWM and a single FET. Then, this voltage powers the half-bridge, which is also PWMed to approximate a sinewave.

    Steve

    http://www.supertex.com/pdf/datasheets/HV860.pdf figure 1
     
  6. Melchior

    Thread Starter New Member

    Feb 2, 2008
    9
    1
    Ahh thank you, I'll still need to decipher what each block does exactly.
     
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