Pixel circuit, method for driving pixel circuit and display apparatus

A pixel circuit comprising a driving transistor, a storage capacitor and a light-emitting device, wherein the driving transistor is connected to a first end of the light-emitting device, wherein a first driving level is inputted into a second end of the light-emitting device, wherein a first end of the storage capacitor is connected to a gate electrode of the driving transistor and wherein the pixel circuit further comprises:

• a reset unit configured to input a reset voltage into the gate electrode of the driving transistor to reset the driving transistor;
• a writing unit configured to write a data voltage into a second end of the storage capacitor and write a reference voltage into a second electrode of the driving transistor after the driving transistor is reset, wherein the writing unit is configured to set the reference voltage based on a threshold voltage of the driving transistor and matched to the reset voltage, such that the reset voltage is less than a sum of the reference voltage and the threshold voltage of the driving transistor to write the threshold voltage of the driving transistor into the storage capacitor;
• a threshold voltage latching unit configured to enable a connection between the gate electrode of the driving transistor and a first electrode of the driving transistor after the driving transistor is reset to latch the threshold voltage of the driving transistor to the gate electrode of the driving transistor;
• a driving level latching unit configured to latch a second driving level to the second end of the storage capacitor after the threshold voltage of the driving transistor is latched to the gate electrode of the driving transistor;
• and
• a light-emitting control unit configured to input the second driving level into the second electrode of the driving transistor after the threshold voltage of the driving transistor is latched to the gate electrode of the driving transistor to (i) control the driving transistor to drive the light-emitting device to emit light, and (ii) compensate for the threshold voltage of the driving transistor and the second driving level via a gate-source voltage of the driving transistor,
• wherein
• the reset unit comprises a reset transistor and is controlled by a reset control signal,
• the reset control signal is inputted into a gate electrode of the reset transistor,
• both the writing unit and the threshold voltage latching unit are controlled by a scanning signal,
• both the driving level latching unit and the light-emitting control unit are controlled by a light-emitting control signal,
• the reset voltage is inputted into a first electrode of the reset transistor,
• a second electrode of the reset transistor is connected to the gate electrode of the driving transistor,
• while in a resetting stage, the reset control signal, the light-emitting control signal and the scanning signal are at a high level and the data voltage is at a low level,
• while in a writing and latching stage, the scanning signal is at the low level and the reset control signal, the light-emitting control signal, the reference voltage and the data voltage are at the high level, and
• while in a light-emitting control stage,
• the light-emitting control signal and the data voltage are at the low level,
• the reference voltage, the reset control signal, and the scanning signal are at the high level, and
• the high level is greater than the low level.