One Circuit, Three Different Voltage Levels


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  1. #10
    Join Date
    Jan 2009
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    Miami, Florida USA
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    Joe,

    Thank you for your comments. Yes, I read the part were you talk about HPWM in your post. That would work if I needed to obtain 3.3V from a PIC running with Vdd=5.0V. But in my case I have a 6.0V rechargeable battery and a 3.3V voltage regulator. Somehow, I need to obtain 12V to feed the GLCD backlight.

    Please, take a look at the attached drawing. In the left lower part it says the power requirements for the backligh. It says "Backlight Vf=9.9V, 12.5 mA per side". However, the datasheet recommends to use 12V with a series current limiting resistor. If you don't feed 12V to the GLCD it will not work. Now, do you see why I had to buy a backlight LED boost driver? They cost about $0.70 a piece.


    Robert
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