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S1D16400 Series
10. REGARDING THE LCD DRIVING POWER
Methods to obtain necessary voltage levels
In order to obtain necessary voltage levels for driving of the LCD, it should be the best to divide the potential
between V
V
5
DD
consideration of the case of using the operation amplifier, the maximum potential level V
be separated to independent terminals.
Nevertheless, if V
of the LCD driver decreases and, therefore, it is suggested that the potential difference between V0
maintained within 0V
As shown in the example of the connection, when using the resistive divider, set the resistance as low as the
power capacity of the system allows.
When a series resistance exist in the power line of V
occurs by I5 at times of signal changes and it becomes unable to maintain the relations of the LCD with
intermediate potentials (V
resistors, it is necessary to stabilize the voltage by their capacity.
Cautions when turning the power on and off
Since the LCD drive system voltage with this LSI is comparatively high, when high voltage is applied to the
LCD drive system leaving the logic power floating or leaving V
are output before the applied voltage to the LCD drive system is stabilized, excess current may flow to break
the LSI. It therefore is suggested to bring the potential of the LCD drive output to the V
drive system voltage gets stabilized using the display-off function (DSPOFF).
When turning the power on or off, follow the sequence below.
When turning on the power.....Logic systems ON →
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When turning off the power.....LCD drive system OFF → Logic system OFF
Insert quick melting fuse in series to the LCD power source for prevention of an excess current flow.
It is necessary to choose the optimum value for the protective resistance matching the capacity of the liquid
crystal cells.
2–12
resistively to drive by means of the voltage follower by the operation amplifier. In
potential drops below the V
0
2.5V. When the operation amplifier is not used, V
~
>
>
>
= V
= V
= V
DD
0
2
potential increasing the potential difference, the capacity
DD
(V
), voltage drop of V
5
DD
>
= V
) leading to breakage of the LSI. When installing protective
3
5
SS
LCD drive system ON
(or turn them on simultaneously).
(or turn them off simultaneously).
EPSON
0
and V
should be connected.
0
DD
(V
) at the LSI current end
5
DD
= –2.6V or over or if LCD drive signals
level until the LCD
0
and V
should
DD
V
be
~
DD
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