SED1565 Datasheet, PDF (48/87 Pages) Epson Company – Direct display of RAM data through the display data RAM

SED1565 Series
Ž When the V/F circuit alone is used
VDD
VSS
External
power
supply
VDD
C2
C2
C2
C2
C2
IRS M/S
VSS2
VOUT
CAP3–
CAP1+
CAP1–
CAP2+
CAP2–
V5
VR
VDD
V1
V2
V3
V4
V5
5 When the built-in power circuit is used to drive a
liquid crystal panel heavily loaded with AC or DC, it
is recommended to connect an external resistor to
stabilize potentials of V1, V2, V3 and V4 which are
output from the built-in voltage follower.
VDD, V0
 When the built-in power is not used
VSS
VDD
VDD
External
power
supply
IRS M/S
VSS2
VOUT
CAP3–
CAP1+
CAP1–
CAP2+
CAP2–
V5
VR
VDD
V1
V2
V3
V4
V5
Examples of shared reference settings
When V5 can vary between –8 and 12 V
Item
C1
C2
Set value
1.0 to 4.7
0.01 to 1.0
Units
µF
µF
R4
R4
C2
V1
V2
V3
V4
R4
R4
V5
Reference set value R4: 100KΩ ~ 1MΩ
It is recommended to set an optimum
resistance value R4 taking the liquid crystal
display and the drive waveform.
Figure 23
* 1 Because the VR terminal input impedance is high, use short leads and shielded lines.
* 2 C1 and C2 are determined by the size of the LCD being driven. Select a value that will stabilize the liquid crystal
drive voltage.
Example of the Process by which to Determine the Settings:
• Turn the voltage regulator circuit and voltage follower circuit ON and supply a voltage to VOUT from the outside.
• Determine C2 by displaying an LCD pattern with a heavy load (such as horizontal stripes) and selecting a C2 that
stabilizes the liquid crystal drive voltages (V1 to V5). Note that all C2 capacitors must have the same capacitance
value.
• Next turn all the power supplies ON and determine C1.
8–46
EPSON