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# Need Help Getting Negative Voltage

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#### cmbeelby

##### New Member
Hello,

I have been tinkering with electronics for a while now and I recently purchased an cheap LCD display which needs a -22V @ 13mA and -17V @ unspecified current in addition to the standard +5V @ 10mA for logic. So I have a wall transformer with selectable output's and already have a "regulator" circuit that I built based on a design at sparkfun.com which will give me a nice +5V output. What I need help with is what parts to buy and how to hook them up so I can generate those negative voltages which I think are for the LCD. In the documentation they refer to the voltages and currents as listed below. The values in parenthesis are actually sub-scripted in the document:

V(DD) = 5V
I(DD) = 10mA Typical, 20mA Max

V(EE) = -22V
I(EE) = 13mA Typical, 20mA Max

V(LCD) = -17V
No I(LCD) is given anywhere that I can see, perhaps it is 10-15mA.

V(SS) = GND

V(DD) - V(EE) = 28V Max
V(DD) - V(SS) = 6V Max