Patent ID: 8624805
Filing Date: 2014-01-07
Classification: G09G

Abstract:
1. An active matrix organic light-emitting diode (AMOLED) display device, comprising: a plurality of sub-pixels arranged in rows and columns, each sub-pixel including at least an organic light-emitting diode (OLED), a first transistor for driving the OLED, a storage capacitor for turning on or off the first transistor according to charges stored in said storage capacitor, and a second transistor for connecting a data line of said each sub-pixel to the storage capacitor and the first transistor; and calibration circuitry configurable to be coupled to at least one of the sub-pixels and adapted to sense pixel transistor current through the first transistor in said one of the sub-pixels, the calibration circuitry forming part of a feedback loop forcing the sensed pixel transistor current to converge to a predetermined target current, wherein said each AMOLED sub-pixel further includes a third transistor connecting the data line with a node between the OLED and the first transistor, wherein the calibration circuitry comprises a first transresistance amplifier, a comparator, a memory, and a column digital-to-analog converter (DAC), wherein the first transresistance amplifier is configured to receive a first pixel transistor current from said one of the sub-pixels via the third transistor and the data line, and to generate a first output voltage based on the first pixel transistor current, wherein the comparator is configured to receive the first output voltage from the first transresistance amplifier, to compare the first output voltage to a first predetermined voltage corresponding to the predetermined target current, and to generate a second output voltage based on the comparison, wherein the memory is configured to store an offset value based on the second output voltage, and wherein the column DAC is configured to generate a second pixel transistor current based on display data and the offset value stored in the memory, and to transmit the second pixel transistor current to the second transistor of said one of the sub-pixels via the data line.