Display driver integrated circuitry (IC) for flat panel displays such as an LCD can be classified into 2 large categories. The first category is the integrated controller and driver IC with embedded display memory, full controller logic, and analog signal drivers. Such an IC can perform all the digital data processing as well as generate all the analog driving signals necessary to drive the display panel, and to display general format data sent. The embedded controller consists of hardware logic for processing the incoming digital data, and for generating graphics control signals and analog control signals. The embedded analog drivers, under the control of the embedded controller, provide both the common and segment analog driving signals to drive the matrix pixels in the display panel.
The second category is the so-called generic driver IC with no embedded display memory and little logic. Separate common driver and segment driver ICs are included for providing the analog driving signals to drive the matrix pixels in the display panel. These common driver and segment driver ICs function under the control of specialized timing interface signals from an external controller with customized application hardware and software. Because there is little controller logic included in these analog drivers, their functionalities depend on extensive control signal processing from the external controller. The external controller receives and processes the general format data to generate the control signals for the separate analog drivers.
A segment driver in the art typically includes two lines of latches to store gray scale and color data. A token signal is input to start reading the data. The token signal is shifted across the first line of latches to enable storing of the data for each segment in a sequential fashion. When all data are stored in the first line of latches, a latch enable is needed to copy all data to a second line of latches. Data value is the second line of latches determines the duration of the current driving period. A line is then displayed as the next line of data is being read. This will be repeatedly performed until the whole frame is displayed.
A common driver in the art needs a row clock from the segment driver. A token signal is input to activate a row. The token signal is shifted across a line of latches so as to activate each row sequentially, a process known as scanning. For a split screen, the token signal is input to two different rows.
Token signals need to be generated for segment and common drivers when LCD controllers are used to drive an organic light emitting diode (“OLED”) drivers in the art. An OLED is an electronic device made by placing a series of organic thin films between two conductors. When electrical current is applied, a bright light is emitted. When used to produce displays, OLED technology produces self-luminous displays that do not require backlighting.
In addition to controller interface difficulties, LCD requires voltage driving in contrast to OLED, which requires current driving. The required level of drive currents is dependent on panel applications and may vary over a wide range. There is thus a general need in the art for an OLED driver device and method overcoming at least the aforementioned shortcomings in the art. A particular need exists in the art for a driver device and method overcoming disadvantages in LCD controller-OLED driver interface difficulties.