EL Backlight PS Suggestions?

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bmichels

New member
After about 10 hours of pulling my hair out, I finally got my 128x64 graphics LCD working with a PIC 16F628. There's a 4-pixel ball bouncing around the screen at 10fps.

Now, I would like to work on getting the backlight working. Any suggestions for a do-it-yourself power supply? I've been searching the web for a high voltage/low current DC-AC power inverters, but haven't found anything useful.


Thanks
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bmichels

New member
Actually, I was hoping for a schematic using a 555 timer or some other scheme that I could build from stuff in my junk box.
 
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mark33andathird

New member
Would a TK65939MTL (available from Digikey) be suitable? Its specs are 400Hz, typical peak to peak voltage is 140V.

http://rocky.digikey.com/WebLib/Toko/Web%20Data/TK6593xM.pdf

Also could you clarify something, the data sheet for the CFAG12864B-WGH-N says it needs a typical 110 Vrms for the backlight (I'm assuming I'm talking about the same product here). You say that the SP4422A should work buts its typical ptp voltage is 160V (160V/(2*1.414)=56V rms, for a sinewave, i think...). Is there some mixup somewhere?
 
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mark33andathird

New member
>a 555 could be used in combination with a transformer couldn't it?
Theoretically, yes. You would need a large ratio of turns. The only widely available transformers that could do this would be would be to run a 120V to 5V transformer in reverse (apply a voltage to the secondary and expect a voltage on the primary). Most transformers of this type are designed to work at 60Hz, not 400Hz so you would expect a lot of inefficiency.
 
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