hd66100 Renesas Electronics Corporation., hd66100 Datasheet - Page 366

• Manufacturer Part Number: hd66100
• Description: H8/3867 Series
• Manufacturer: Renesas Electronics Corporation.

2. Example of operation (with 1/3 bias drive)
a. During charging period Tc in the figure, the potential is divided among pins V1, V2, and
b. In the following discharging period, Tdc, charging is halted and the charge accumulated in
c. At this time, a slight voltage drop occurs due to the discharging; optimum values must be
d. In this way, the capacitors connected to V1, V2, and V3 are repeatedly charged and
e. As can be seen from the above description, the capacitances and charging/discharging
f. The actual capacitor capacitances and charging/discharging periods must be determined
V0
V1
V2
V3
V3 by the built-in split-resistance (the potential of V2 being 2/3 that of V1, and that of V3
being 1/3 that of V1), as shown in figure 13.14, and external capacitors C1, C2, and C3 are
charged. The LCD panel is continues to be driven during this time.
each capacitor is discharged, driving the LCD panel.
selected for the charging period and the capacitor capacitances to ensure that this does not
affect the driving of the LCD panel.
discharged in the cycle shown in figure 13.14, maintaining the potentials and continuously
driving the LCD panel.
periods of the capacitors are determined by the current dissipation of the LCD panel used.
The charging/discharging periods can be selected with bits CDS3 to CDS0.
experimentally in accordance with the current dissipation requirements of the LCD panel.
An optimum current value can be selected, in contrast to the case in which a direct current
flows constantly in the built-in split-resistance.
Figure 13.14 Example of Low-Power-Consumption LCD Drive Operation
C3
C2
C1
V1 potential
V2 potential
V3 potential
Power supply voltage fluctuation in 1/3 bias system
period Tc
Charging
V1 2/3
V1 1/3
Discharging
period Tdc
Vd1
Vd2
Vd3
Voltage drop
associated with
discharging due
to LCD panel
driving
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