Power Control - Epson S1C63666 Technical Manual

4.2 Power Control

4.2.1 Configuration of power supply circuit
The S1C63666 has built-in power supply circuits shown in Figure 4.2.1.1 so the voltages to drive the CPU,
internal logic circuits, oscillation circuits and LCD driver can be generated on the chip.
External
power
supply
Voltage regulator for OSC1 oscillation circuit
This voltage regulator always operates to generate the V
OSC1 oscillation circuit.
Low-speed operation voltage regulator
The low-speed operation voltage regulator always operates to generate the V
for driving the internal logic circuits. The V
CPU and internal logic circuits when they are driven with the OSC1 clock (32 kHz). V
switched using software according to the operating clock.
High-speed operation voltage regulator
The high-speed operation voltage regulator generates the V
OSC3 oscillation circuit and the internal logic circuits in high-speed mode. Since this regulator stops
normally, turn it on using the VDC1 register (VDC1 = "1") and switch the internal logic operating
voltage to V using the VDC0 register before starting the OSC3 oscillation.
D3
LCD system voltage circuit
The LCD system voltage circuit generates the LCD drive voltage. This circuit can be turned on and off
using the LPWR register. Turn this circuit on (LPWR = "1") before starting display on the LCD.
The LCD system voltage circuit generates V
other voltages (V
C2
software in 16 steps (0.95 to 1.40 V). Refer to Section 4.8, "LCD Driver", for control of the V
(contrast). This circuit does not operate when an external power supply is selected by mask option for
driving the LCD.
S1C63666 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Power Control)
CC
CD
V
DDA
V
Voltage
DD
halver
V
D2
V
VDC3
V
C1
V
C2
V
C3
CA
CB
+
V
OSC
VDC2
V
D1
V
SS
V
SSA
Fig. 4.2.1.1 Built-in power supply circuit
= 2V , V = 3V ) by boosting V
C1 C3 C1
LCD system voltage circuit
LPWR
=1/2 V
D2 DD
LCD system
voltage regulator
V
C1
Voltage booster
Voltage regulator for
OSC1 oscillation circuit
Low-speed operation
voltage regulator
VDC0
High-speed operation
voltage regulator
VDC1
voltage (0.98 V Typ.) for driving the
OSC
voltage is used as the V
D1L
voltage (2.0 V Typ.) for driving the
D3
with the built-in voltage regulator, and generates two
C1
. The V
C1 C1
EPSON
R/f
converter
V
C1
V
C2
LCD driver
V
C3
OSC1
V
OSC
oscillation circuit
V
D1L
V
D1 CPU,
internal circuits
V
D3
OSC3
oscillation circuit
voltage (1.25 V Typ.)
D1L
operating voltage of the
D1
D1
voltage value can be adjusted using
should be
voltage
C1
25