ST8024

Ver 2.1

Page 15/28

2009/08/19

8

PRECAUTIONS

Precautions when connecting or disconnecting the power supply

This IC has a high-voltage LCD driver, so it may be permanently damaged by a high current which

may flow if voltage is supplied to the LCD drive power supply while the logic system power supply

is floating. The details are as follows,

When connecting the power supply, connect the LCD drive power after connecting the logic

system power. Furthermore, when disconnecting the power, disconnect the logic system power

after disconnecting the LCD drive power

It is advisable to connect the serial resistor (50 to 100

the system as a current limiter. Set up a suitable value of the resistor in consideration of the

display grade.

And when connecting the logic power supply, the logic condition of this IC inside is insecure.

Therefore connect the LCD drive power supply after resetting logic condition of this IC inside on

/DISPOFF function. After that, cancel the /DISPOFF function after the LCD drive power supply

has become stable. Furthermore, when disconnecting the power, set the LCD drive output pins to

level LGND on /DISPOFF function. Then disconnect the logic system power after disconnecting

the LCD drive power.

When connecting the power supply, follow the recommended sequence shown here

.

LGND

LGND

GND

/DISPOFF