ssd1329 ETC-unknow, ssd1329 Datasheet - Page 21

• Manufacturer Part Number: ssd1329
• Description: 128 X 128 Oled Segment / Common Driver With Controller Equips With 16 Gray Scale Levels And 64 Hard Icon Lines
• Manufacturer: ETC-unknow

There are four phases to driving an OLED a pixel. In phase 1, the pixel is reset by the segment driver to V
in order to discharge the previous data charge stored in the parasitic capacitance along the segment electrode.
The period of phase 1 can be programmed by command B1h A[3:0] from 1 to 16 DCLK. An OLED panel
with larger capacitance requires a longer period for discharging.
In phase 2, first pre-charge is performed. The pixel is driven to attain the corresponding voltage level V
V
programmed in length from 1 to 16 DCLK by command B1h A[7:4]. If the capacitance value of the pixel of
OLED panel is larger, a longer period is required to charge up the capacitor to reach the desired voltage.
In phase 3, the OLED pixel is driven to the targeted driving voltage through second pre-charge. The second
pre-charge can control the speed of the charging process. The period of phase 3 can be programmed by
command BBh.
Last phase (phase 4) is current drive stage. The current source in the segment driver delivers constant current
to the pixel. The driver IC employs PWM (Pulse Width Modulation) method to control the gray scale of each
pixel individually. The wider pulse widths in the current drive stage results in brighter pixels and vice versa.
This is shown in the following figure.
After finishing phase 4, the driver IC will go back to phase 1 to display the next row image data. This four-
step cycle is run continuously to refresh image display on OLED panel.
The length of phase 4 is defined by command B7h “Set Default Gray Scale Table” or B8h “Set Gray Scale
Table”. In the table, the gray scale is defined in incremental way, with reference to the length of previous
table entry.
SSD1329
LSS
Segment
Voltage
. The amplitude of V
V
V
P
LSS
Phase1
Rev 1.1
Phase2
P 21/58
P
can be programmed by the command BCh. The period of phase 2 can be
Figure 8-6: Gray Scale Control by PWM in Segment
Phase3
Dec 2005
Phase4
OLED
Panel
drives pixel brighter
Wider pulse width
Solomon Systech
P
from
LSS