SIC63616-(Rev. 1.0) NO. P75
3240-0412
DBON: Power supply voltage booster/halver boost mode On/Off register (FF02H•D0)
Activates the power supply voltage booster/halver in boost mode.
When "1" is written: Booster On
When "0" is written: Booster Off
Reading: Valid
When "1" is written to DBON, the power supply voltage booster/halver activates in boost mode and almost
doubles the V
DD
voltage to generate the V
D2
voltage. Turn the power supply voltage booster/halver on
when driving the LCD system voltage regulator with V
D2
(V
C2
reference voltage, V
DD
= 1.6 to 2.5 V). When
"0" is written to DBON, the voltage boost operation is deactivated. Be sure to set DBON to "0" (Off) when
driving the LCD system voltage regulator with V
DD
. Furthermore, do not set both DBON and HLON to "1".
At initial reset, this register is set to "0".
VCSEL: LCD system voltage regulator power source switch register (FF02H•D2)
Selects the power voltage for the LCD system voltage regulator.
When "1" is written: V
D2
When "0" is written: V
DD
Reading: Valid
When "1" is written to VCSEL, the LCD system voltage regulator is driven with V
D2
generated by the power
supply voltage booster/halver. Before this setting is made, it is necessary to write "1" to DBON to activate
the power supply voltage booster (boost mode). Furthermore, do not switch the power voltage to V
D2
for at
least 1 msec after the power supply voltage booster/halver is turned on to allow V
D2
to stabilize. When "0"
is written to VCSEL, the LCD system voltage regulator is driven with V
DD
.
At initial reset, this register is set to "0".
Note: Do not set DBON to "1" (boost mode) and VCSEL to "1" (driving with V
D2
) if the supply voltage V
DD
exceeds 2.5 V, as it may cause damage of the IC.
LPWR: LCD system voltage regulator On/Off register (FF03H•D0)
Turns the LCD system voltage regulator on and off.
When "1" is written: On
When "0" is written: Off
Reading: Valid
When "1" is written to LPWR, the LCD system voltage regulator goes on and generates the LCD drive
voltages. When "0" is written, all the LCD drive voltages go to V
SS
level.
It takes about 100 msec for the LCD drive voltages to stabilize after starting up the LCD system voltage
regulator by writing "1" to LPWR.
At initial reset, this register is set to "0".
VCHLMOD: LCD system voltage regulator heavy load protection On/Off register (FF03H•D3)
Enables heavy load protection function for the LCD system voltage regulator.
When "1" is written: On
When "0" is written: Off
Reading: Valid
By writing "1" to VCHLMOD, the LCD system voltage regulator enters heavy load protection mode to
minimize degradation in display quality when fluctuations in the supply voltage occurs due to driving a
heavy load. The heavy load protection function is effective when the OSC3 clock is used or the buzzer/FOUT
signal is being output. However, heavy load protection mode increases current consumption compared with
normal operation mode. Therefore, do not set heavy load protection mode unless it is necessary.
At initial reset, this register is set to "0".