UPD16488AP NEC [NEC], UPD16488AP Datasheet - Page 30

• Manufacturer Part Number: UPD16488AP
• Description: 1/92 DUTY LCD CONTROLLER/DRIVER WITH FOUR-LEVEL GRAY SCALE, ON-CHIP RAM
• Manufacturer: NEC [NEC]

5.6
voltage follower.
supply circuit's booster, voltage regulator (also called V regulator), and voltage follower (V/F). This makes it possible to
jointly use an external power supply together with certain functions of the on-chip power supply. Table 5-7 shows the
function that controls the 3-bit data in the power system control register 1 (R32) and Table 5-8 shows a reference chart of
combinations.
5.6.1 Booster
Since the booster uses signals from the on-chip oscillator, either the oscillator must be operating or a display clock must be
input from an external source.
impedance should be kept as low as possible. The number of boost levels is set using the FBS2, FBS1, and FBS0 flags in
the power system control 3 (R34), as shown in Table 5-9.
Table 5-10.
The power supply circuit supplies the voltage needed to drive the LCD. It includes a booster, voltage regulator, and
In the power supply circuit, the power system control register 1 (R32) is used to control the ON/OFF status of the power
A booster that boosts the LCD driving voltage by 2 to 9 times is incorporated in the power supply circuit.
The booster uses pins C1
Figure 5-11 describes the connection method for boost levels and capacitors.
The partial booster is settings are made using the BST1 and BST0 flags in the power system control 3 (R34), as shown in
Caution If a capacitor is connected to a boost-related system pin that is not for one of these set boost levels,
<1> Use on-chip power supply
<2> Use V regulator and V/F only
<3> Use V/F only
<4> Use external power supply only
Note The boost-related system pins are indicated as pins C1
30
Power Supply Circuit
current consumption may increase. Therefore, do not connect any capacitors beyond the number of
set boost levels. This also applies for the CA1 pin, used to regulate the boost levels.
Use Status
OP2
OP1
OP0
Table 5-7. Control Values of Bits in Power System Control 1
+
, C1 to C9
OP2 OP1 OP0 Booster V Regulator
Table 5-8. Reference Chart of Combinations
Booster control bit
Voltage regulator (V regulator) control bit
Voltage follower (V/F) control bit
1
0
0
0
+
, C9 for normal boost and pins C1A and V
1
1
0
0
Item
Data Sheet S15745EJ2V0DS
1
1
1
0
disable
disable
disable
enable
+
disable
disable
enable
enable
, C1 to C9
+
disable
enable
enable
enable
, C9 , and C1A.
V/F
ON
ON
ON
1
Status
V
V
V
V
V
DD2
Power Supply
DD2
OUT
OUT
OUT
LCD
External
, AMP
,
for boost regulation. The wire
to V
Input
OFF
OFF
OFF
0
LC4
OUT
Boost-Related
Not connected
Not connected
Not connected
System Pins
Used
PD16488A
Note