Display devices for providing driving currents irrelevant to threshold voltages of driving transistors and driving voltages of light-emitting diodes

A display device includes pixel units. Each pixel unit includes a driving transistor, a switch transistor, a reset transistor, a light-emitting element, and a control unit. The driving transistor has a control terminal, a first terminal coupled to a first operation voltage source and a second terminal. The reset transistor is coupled to the control terminal of the driving transistor. The light-emitting element is coupled to the switch transistor in series between the second terminal of the driving transistor and a second operation voltage source. The control unit stores a threshold voltage of the driving transistor and a driving voltage of the light-emitting element according to a voltage level of the second terminal of the driving transistor. The control unit changes a voltage level of the control terminal of the driving transistor according to the stored threshold voltage, the stored driving voltage, and a corresponding data signal.