E0C88832/88862 TECHNICAL MANUAL
EPSON
11
2 POWER SUPPLY
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:
2.4 V to 5.5 V
Low power mode:
1.8 V to 3.5 V
High speed mode:
3.5 V to 5.5 V
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
DD
(+) and
V
SS
(GND), all the voltages needed for the internal
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
> for driving the internal
logic circuits and the OSC3 oscillation circuit. The
V
D1
voltage can be selected from the following
three types: 1.3 V for low-power mode, 2.2 V for
normal mode and 3.3 V for high-speed mode.
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
C1
> to <V
C5
>. In 1/5 bias
mode, V
C1
is generated by halving V
C2
output from
the LCD system voltage regulator and V
C3
to V
C5
are
generated by boosting V
C2
. These five voltages can
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
C2
voltage level
becomes equal to the V
C3
voltage level. When using
with 1/4 bias configuration, the mask option also
allows selection of V
C1
standard mode that
generates V
C2
to V
C5
by boosting V
C1
.
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
C1
–V
C5
outputs for driving
external circuits.
Fig. 2.2.1 Configuration of power supply circuit
V
DD
V
V
OSC
D1
V
C1
V
C3
V
C4
V
C5
CA
CB
CC
CD
CE
CF
CG
V
SS
LCD system
power supply
circuit
LCD driver
V
D1
V
C1
–V
C5
V
OSC
V
C2
External
power
supply
OSC3, OSC4
OSC1, OSC2
Regulator
Booster/reducer
Internal logic
voltage regulator
OSC3
oscillation circuit
Internal voltage
setting circuit
Oscillation system
voltage regulator
Internal circuit
OSC1
oscillation circuit
COM0~COM15
COM16~COM31/SEG66~SEG51
SEG0~SEG50
COM0~COM15
COM16~COM31/SEG66~SEG51
SEG0~SEG40
E0C88832
E0C88862
Содержание 0C88832
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