SSD1812_ View Datasheet(PDF) - Solomon Systech
Part Name
Description
Manufacturer
SSD1812_ Datasheet PDF : 14 Pages
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APPLICATION NOTE 4: REFERENCE CIRCUIT EXAMPLE
FOR HIGH LOADING SITUATIONS
When the built-in power circuit is used to drive a liquid crystal display panel which is heavily loaded with AC or DC sig-
nals, it is recommended to connect a series of external resistors to stabilize potentials of VL2, VL3, VL4 and VL5 which
are output from the built-in voltage divider (follower). The number of resistors used depends on the situations of the pan-
el. SSL recommends customer to try in order to obtain the best result.
When installing the COG, or in special cases when designs that may cause high loading situations for the driver IC. It
is necessary to consider the fact that there exists a resistance of the ITO wiring occurring between the driver chip and
the externally connected parts (such as capacitors and resistors). By the influence of this resistance, non-conformity
may occur with the indications on the liquid crystal display.
Therefore, when installing the COG design the module paying sufficient considerations to the following situations:
- suppress the resistance occurring between the driver chip pin to the externally connected parts as much as possible.
- suppress the resistance connecting to the power supply pin of the driver chip.
- make various COG module samples with different ITO sheet resistance to select the module with the sheet resistance
with sufficient operation margin.
As a rule of thumb, it is more preferred to use lower resistance ITO glass panels. Normally we recommend customers
to use below 15ohm square ITO glass panels.
Example:
Please find the following circuit a recommendation to LCD module designers that in case of large loading situations, it
is possible to maximize the stability of the Voltage booster output.
SSD181X/SSD1815A/SSD1815B Series
VDD
VL2
VL3
VL4
VL5
VL6
R3
R4
R2
R1
C5
C4
C3
C2
C1
VDD
Remarks: 1. C1 ~ C5 = 0.1 ~ 0.47uF
2. R1 ~ R4 = 100k ohm~ 1M ohm
SOLOMON
Application of SSD181X/SSD1815A/SSD1815B to Existing LCD Modules
7
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