Modules require +5V at 1 to 10 milliamps. Extended temperature
and some high contrast modules require higher voltage, also at low
current. Inexpensive ICs convert +5V to -5V efficiently. If the
display has backlighting, required power must also be budgeted.
The power supply does not have to "lock-on" +5V but it
must not "spike" beyond the module's absolute maximums.
A module's logic circuits have 3 connections to the power supply:
VDD (+5VDC); VSS (Ground); and VO (viewing angle adjustment), sometimes
called contrast or bias control. The diagrams below show typical
Contrast can also be controlled digitally with a digital potentiometer