Organic light emitting diode display apparatus and pixel circuit thereof

An organic light emitting diode display apparatus, comprising:

• a power circuit configured to provide a high voltage and a system low voltage;
• and
• a pixel circuit, comprising:
• a switch unit, receiving a data voltage, a scan signal and a ground voltage, and providing the data voltage or the ground voltage according to the scan signal;
• a capacitor, a first terminal of the capacitor being coupled to the switch unit to receive the data voltage or the ground voltage;
• a first transistor, a first terminal of the first transistor being coupled to the high voltage, a second terminal of the first transistor being coupled to a second terminal of the capacitor, and a control terminal of the first transistor receiving a first switch signal;
• a second transistor, a first terminal of the second transistor being coupled to the high voltage, and a control terminal of the second transistor being coupled to the second terminal of the capacitor;
• a third transistor, a first terminal of the third transistor being coupled to a second terminal of the second transistor, a second terminal of the third transistor being coupled to the second terminal of the capacitor, and a control terminal of the third transistor receiving a second switch signal;
• and
• an organic light emitting diode, an anode of the organic light emitting diode being coupled to the second terminal of the second transistor, and a cathode of the organic light emitting diode being coupled to the system low voltage;
• wherein in a pre-charging period, the first terminal of the capacitor receives the data voltage through the switch unit and the second terminal of the capacitor receives the high voltage through the turned-on first transistor, in a programming period, the first terminal of the capacitor receives the data voltage through the switch unit and the second terminal of the capacitor receives the high voltage that is encoded through the turned-on second and third transistors, and in a display period, the first terminal of the capacitor receives the ground voltage through the switch unit and the first and third transistors are turned-off.