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2 POWER SUPPLY
In this section, we will explain the operating
voltage and the configuration of the internal power
supply circuit of the E0C88832/88862.
2.1 Operating Voltage
The E0C88832/88862 operating power voltage is as
follows:
Normal mode:
Low power mode:
High speed mode:
If supply voltage drops below level 0 (see Chapter
7, "ELECTRICAL CHARACTERISTICS"), the
system is automatically reset by a supply voltage
detection (SVD) circuit described in the latter. This
function can be selected by mask option.
2.2 Internal Power Supply Circuit
The E0C88832/88862 incorporates the power supply
circuit shown in Figure 2.2.1. When voltage within
the range described above is supplied to V
V
(GND), all the voltages needed for the internal
SS
circuit are generated internally in the IC.
Roughly speaking, the power supply circuit is
divided into three sections.
The internal logic voltage regulator generates the
operating voltage <V
D1
logic circuits and the OSC3 oscillation circuit. The
V
voltage can be selected from the following
D1
three types: 1.3 V for low-power mode, 2.2 V for
normal mode and 3.3 V for high-speed mode.
V
DD
External
power
supply
V
D1
V
OSC
V
C1
V
C2
V
C3
V
C4
V
C5
CA
CB
CC
CD
CE
CF
CG
V
SS
E0C88832/88862 TECHNICAL MANUAL
2.4 V to 5.5 V
1.8 V to 3.5 V
3.5 V to 5.5 V
(+) and
DD
> for driving the internal
Internal logic
V
D1
voltage regulator
Oscillation system
V
OSC
voltage regulator
LCD system
power supply
circuit
V
–V
C1
C5
Regulator
Booster/reducer
Fig. 2.2.1 Configuration of power supply circuit
It should be selected by a program to switch
according to the supply voltage and oscillation
frequency.
See Section 5.3, "Oscillation Circuits and Operating
Mode", for the switching of operating mode.
The oscillation system voltage regulator generates
the operating voltage <VOSC> for the OSC1
oscillation circuit.
The LCD system power supply circuit generates the
LCD drive voltages <V
mode, V
is generated by halving V
C1
the LCD system voltage regulator and V
generated by boosting V
be supplied from outside the IC by mask option.
Furthermore, 1/4 bias drive can be selected by
mask option. In this case, the V
becomes equal to the V
with 1/4 bias configuration, the mask option also
allows selection of V
generates V
to V
C2
See Chapter 7, "ELECTRICAL CHARACTERIS-
TICS" for the voltage values.
In the E0C88832/88862, the LCD drive voltage is
supplied to the built-in LCD driver which drives
the LCD panel connected to the SEG and COM
terminals.
Note: Do not use the V
external circuits.
Internal voltage
setting circuit
OSC3
oscillation circuit
Internal circuit
OSC1
oscillation circuit
LCD driver
EPSON
2 POWER SUPPLY
> to <V
>. In 1/5 bias
C1
C5
output from
C2
C3
. These five voltages can
C2
voltage level
C2
voltage level. When using
C3
standard mode that
C1
by boosting V
.
C5
C1
–V
outputs for driving
C1
C5
OSC3, OSC4
OSC1, OSC2
E0C88832
COM0~COM15
COM16~COM31/SEG66~SEG51
SEG0~SEG50
COM0~COM15
COM16~COM31/SEG66~SEG51
SEG0~SEG40
E0C88862
to V
are
C5
11
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