Asimple and useful driving circuit with constant current source used for the small size PM-OLED display was introduced.This small size(30 mm×38 mm)matrix-type OLED with 64×56 pixels was devised by our laboratory.As the luminance current characteristics of OLED was linear

the constant current driving method was employed to wipe out the cross talk caused by the voltage drops along the columns(ITO anode) of the display.The column driving circuit with constant current sources as well as the row driver were presented in this article.In the PM addressing mode

the matrix-type display was scanned line by line over the frame time.When a line was selected

each pixel in the line was fed with a constant current pulse

constructing the pattern displayed on the OLED matrix.In order to obtain a good image quality

the design of the current source seems very important.This paper describes a current source that uses the transistors and resisters.And this current source relys on feed back techniques to achieve regulation.Some measurements were taken to improve its stability and temperature characteristics correspondingly.Abrief analysis was also made to gain insight into the behavior of the transistors used in the current source.The constant current sources have been proved efficient in several experiments.They are economical

taking a small area and stable

contributing a new idea to improve the PM-OLED driving method.