SED1565 Datasheet, PDF (35/87 Pages) Epson Company – Direct display of RAM data through the display data RAM

SED1565 Series
+
C1
C1
+
C1
C1
+
VSS2
VOUT
CAP3–
CAP1+
CAP1–
CAP2–
CAP2+
+
C1
+
C1
C1
+
VSS2
VOUT
CAP3–
CAP1+
CAP1–
CAP2–
CAP2+
+
C1
VSS2
VOUT
CAP3–
+
CAP1+
C1
CAP1–
CAP2–
OPEN CAP2+
4 x step-up voltage circuit
3 x step-up voltage circuit
2 x step-up voltage circuit
VDD = 0V
VSS2 = –3V
VDD = 0V
VSS2 = –3V
VDD = 0V
VSS2 = –5V
VOUT = 4 x VSS2 = –12V
VOUT = 3 x VSS2 = –9V
VOUT = 2 x VSS2 = –10V
4x step-up voltage relationships 3x step-up voltage relationships 2x step-up voltage relationships
Figure 7
* The VSS2 voltage range must be set so that the VOUT terminal voltage does not exceed the absolute maximum rated
value.
The Voltage Regulator Circuit
The step-up voltage generated at VOUT outputs the
liquid crystal driver voltage V5 through the voltage
regulator circuit.
Because the SED1565 Series chips have an internal
high-accuracy fixed voltage power supply with a 64-
level electronic volume function and internal resistors
for the V5 voltage regulator, systems can be constructed
without having to include high-accuracy voltage
regulator circuit components.
Moreover, in the SED1565 Series, three types of thermal
gradients have been prepared as VREG options: (1)
approximately -0.05%/°C (2) approximately -0.2%/°C,
and (3) external input (supplied to the VRS terminal).
(A) When the V5 Voltage Regulator Internal
Resistors Are Used
Through the use of the V5 voltage regulator internal
resistors and the electronic volume function the liquid
crystal power supply voltage V5 can be controlled by
commands alone (without adding any external resistors),
making it possible to adjust the liquid crystal display
brightness. The V5 voltage can be calculated using
equation A-1 over the range where | V5 | < | VOUT |.
EPSON
8–33