A display system, a driver for driving the display array, method of operating the display system and a pixel circuit in the display system are provided. The driver includes: a bidirectional current source having a convertor coupling to a time-variant voltage, for converting the time-variant voltage to the current. The pixel circuit includes: a transistor for providing a pixel current to a light emitting device; and a storage capacitor electrically coupling to the transistor, the capacitor coupling to a time-variant voltage in a predetermined timing for providing a current based on the time-variant voltage. The method includes: in a first cycle in a programming operation, changing a time-variant voltage provided to a storage capacitor in a pixel circuit, from a reference voltage to a programming voltage, the storage capacitor electrically coupling to a driving transistor for driving a light emitting device; and in a second cycle in the programming operation, maintaining the time-variant voltage at the programming voltage. The method includes: in a programming operation, providing programming data to a pixel circuit from a data line, the pixel circuit including a transistor coupling to the data line and a storage capacitor; and in a driving operation, providing, to the storage capacitor in the pixel circuit via a power supply line, a time-variant voltage for turning on a light emitting device. The pixel circuit, which includes: an organic light emitting diode (OLED) device having an electrode and an OLED layer; and an inter-digitated capacitor having a plurality of layers.