Patent ID: 9275578
Filing Date: 2016-03-01
CPC Classification: G09G

Claim Text:
1. A method for operating a pixel circuit for an active matrix display system, comprising: initiating a programming period of the pixel circuit by activating a triode switch circuit of the pixel circuit to transfer a programming data voltage on a data line of the display system to a storage capacitor of the pixel circuit during the programming period, wherein the storage capacitor is connected to an output node of the triode switch circuit, wherein the triode switch comprises a first resistive element and at most two diodes comprising a first diode, and a second diode, and wherein activating the triode switch circuit comprises placing both the first and second diodes of the triode switch in a forward-biased state to pre-charge the storage capacitor using the programming data voltage on the data line; and initiating an illumination period of the pixel circuit by deactivating the triode switch circuit of the pixel circuit to isolate the storage capacitor from the data line and charge the storage capacitor from the programming data voltage to a voltage that turns on an organic light emitting diode during the illumination period of the pixel circuit, wherein deactivating the triode switch circuit comprises placing both the first and second diodes of the triode switch in a reverse-biased state, and wherein the storage capacitor is charged during the illumination period based, in part, on a time constant of a RC circuit formed by the storage capacitor and a second resistive element connected between the output node of the triode switch circuit and a power supply node.