Epson S1C17624 - 4 Power Supply; 4.1 Power Supply Voltage (VDD); 4.2 Analog Power Supply Voltage (AVDD); 4.3 Internal Power Supply Circuit

4 POWER SUPPLY
S1C17624/604/622/602/621 TECHNICAL MANUAL Seiko Epson Corporation
4-1
Power Supply4
Power Supply Voltage (V4.1
DD
)
The operating voltage range of the S1C17624/604/622/602/621 is as follows:
For normal operation: V
DD = 1.8 V to 3.6 V
For Flash programming: V
DD = 2.7 V to 3.6 V
Su p pl y a vo l t ag e w i th in th e ra n g e to th e V
DD p i n s w it h th e V S S p in s a s th e G ND lev el . T he
S1C17624/604/622/602/621 provides two or more V
DD and VSS pins. Do not leave any power supply pins open and
be sure to connect them to + power source and GND.
Analog Power Supply Voltage (AV4.2
DD
)
The analog power supply pin (AVDD) is provided separately from the VDD pin in order that the digital circuits do
not affect the analog circuits (A/D converter). The AV
DD pin is used to supply an analog power voltage and the VSS
pin is used as the analog ground. The following voltage is enabled for AV
DD:
AV
DD = VDD = 1.8 V to 3.6 V (VSS = GND)
Note: Be sure to supply the same voltage as V
DD to the AVDD pin even if the analog circuit is not used.
Noise on the analog power lines decrease the A/D converting precision, so use a stabilized power supply and make
the board pattern with consideration given to that.
Internal Power Supply Circuit4.3
The S1C17624/604/622/602/621 has a built-in power supply circuit shown in Figure 4.3.1 to generate all the power
voltages required for the internal circuits. The power supply module consists of two circuits.
3.1 Power Supply CircuitTable 4.
Circuit Power supply circuit Output voltage
Oscillator and internal logic circuits Internal logic voltage regulator VD1
LCD driver LCD system voltage regulator VC1 to VC3
VD1
External
power
supply
Oscillator
Internal logic
voltage regulator
Internal circuit
OSC1, OSC2
OSC3, OSC4
V
D1
V
C1
VC2
VC3
CA
CB
V
SS
AVDD
VDD
A/D converter
AINx
LCD driver
COMx
SEGx
LCD system
voltage regulator
VC1–VC3
VCSEL
LHVLD
VD1MD
HVLD
3.1 Configuration of Power Supply CircuitFigure 4.
Note: Be sure to avoid using the VD1 and VC1–VC3 pin outputs to drive external circuits.