A circuit has a first portion configured to act as a shift register to provide an output signal via an output terminal, and a second portion configured to act as an inverter to invert the output signal at the output terminal of said first portion from a logic high state to a logic low state or vice versa. This is to forcibly turn off one or more transistors in a pixel circuit that provides subpixel or pixel-related control in an OLED display, such that an anode voltage of an organic light emitting diode does not exceed a turn-on voltage thereof.