Patent ID: 7075238

Claim:
An organic light emitting display unit, comprising: a capacitor having a first end and a second end, the first end and the second end selectively and respectively receives a data signal and a reference voltage according to a scan signal; a first P-type metal oxide semiconductor (PMOS) transistor having a gate coupled to the first end of the capacitor; and an organic light emitting diode (OLED) coupled to the first PMOS transistor; wherein when the scan signal is enabled, the first end and the second end of the capacitor respectively receive the data signal and the reference voltage, and when the scan signal is disabled, a source of the first PMOS transistor is biased at a main voltage and coupled to the second end of the capacitor such that a voltage difference between the source and the gate of the first PMOS transistor substantially equals a crossover voltage of the capacitor, and the first PMOS transistor outputs a driving current, which corresponds to a difference between the data signal and the reference voltage, to the OLED.