A pixel circuit for an organic light emitting diode (OLED) display is disclosed. One inventive aspect includes an organic light emitting diode, a first transistor, a second transistor, a first capacitor connected to a second node and a fixed voltage source, a third transistor, a fourth transistor, a second capacitor connected to the fourth transistor and a third node, a first control transistor and a second control transistor. The fourth transistor is connected to the first and third nodes and is turned off when an emission control signal is supplied to an emission control line and turned on otherwise. The first control transistor is connected to the third node and the first power source and is turned on when a first control signal is supplied.