1. Field of the Invention
This invention relates to a driving apparatus for a plasma display panel.
2. Description of the Related Art
A plasma display panel (designated as "PDP" hereinafter) is known as an image display that provides a reduction in its thickness and an increase in its screen size. The PDP has a number of effective features not found in conventional CRT displays. There is a need for a reduction in manufacturing cost and an improved quality of the plasma display panel.
Generally, a PDP comprises a plurality of row electrodes arranged in parallel and a plurality of column electrodes extending perpendicularly to the row electrodes. A display cell is provided at each point of the row and column electrodes. Particularly, in a color type of PDP, an additional row electrode is arranged near the row electrode to be paired so as to prevent fluorescent layer in the cell from wearing due to ion impact. Surface discharge between the pair of row electrodes is utilized as a light source for the color type of PDP.
The PDP described above requires a plurality of electrodes and a driving circuit for controlling the display for every cell. For providing a PDP having a larger screen size, an immense amount of discharge current is required. Particularly, the integration of the plurality of driving circuits into one chip requires an IC having a large capacity of power supply. Thus, this is not practical in terms of heat generation and manufacturing cost. To overcome the above problem, a conventional PDP driving apparatus divides the group of pairs of row electrodes into a plurality of sub-blocks in order to reduce a load on one IC. Each of sub-blocks then includes one pulse generator. In addition, a driving apparatus is provided for selectively relaying output pulses from the pulse generator.
However, if there is some difference between impedance and output level of pulses of the pulse generators, the levels of pulses supplied from the driving circuits to the pair of row electrodes may differ from one sub-block to another. In such a case, a problem arises in that a luminance distribution is not uniform on the display surface of the PDP.