Driving circuit and display device
Embodiments of the present disclosure are related to a driving circuit and a display device, by applying an initialization voltage to a sensing node between a driving transistor and a light-emitting element and sensing a voltage change of the sensing node according to driving the light-emitting element, a threshold voltage of the light-emitting element can be detected without turning-on the driving transistor. Furthermore, by turning on the driving transistor and falling a voltage of the sensing node before sensing the voltage of the sensing node, a voltage lower than the threshold voltage of the light-emitting element can be sensed and a variation of a characteristic value of the light-emitting element is detected, thus a circuit for sensing the characteristic value of the light-emitting element can be implemented easily.
1. A display device, comprising:
a plurality of subpixels disposed in a display panel;
a plurality of sensing lines electrically connected to at least one of the plurality of subpixels; and
a driving circuit configured to drive the plurality of sensing lines,
wherein each of the plurality of subpixels comprises,
a light-emitting element;
a driving transistor configured to drive the light-emitting element; and
a sensing transistor electrically connected between a sensing node which the light-emitting element and the driving transistor are electrically connected to each other and the sensing line,
wherein the display device is configured in that, during a sensing period for detecting a characteristic value of the light-emitting element,
in a first period, the sensing transistor becomes a turned-on state and an initialization voltage is supplied through the sensing line,
in a second period, a supply of the initialization voltage to the sensing line is stopped,
in a third period, the driving transistor becomes a turned-on state, and
in a fourth period, the driving transistor is a turned-off state when a sensing voltage of the sensing node is detected.
2. The display device of claim 1 , wherein, in the third period, an auxiliary data voltage is supplied to a gate node of the driving transistor, and the auxiliary data voltage is smaller than the initialization voltage.
3. The display device of claim 2 , wherein the auxiliary data voltage supplied to a subpixel where a first driving transistor is disposed among the plurality of subpixels is different from the auxiliary data voltage supplied to a subpixel where a second driving transistor is disposed among the plurality of subpixels.
4. The display device of claim 2 , wherein, in the third period, a voltage of a driving node which the driving transistor is electrically connected to a driving voltage line is smaller than the auxiliary data voltage.
5. The display device of claim 2 , wherein, in the first period and the second period, a sensing data voltage is supplied to the gate node of the driving transistor, and the sensing data voltage is smaller than the auxiliary data voltage.
6. The display device of claim 1 , wherein a length of the third period is smaller than a length of the second period.
7. The display device of claim 1 , wherein a degree that a voltage of the sensing node is changed in the third period is greater than a degree that a voltage of the sensing node is changed in the second period.
8. The display device of claim 1 , wherein a voltage of the sensing node decreases in the third period.
9. The display device of claim 1 , wherein the driving transistor is a turned-off state in the first period and the second period.
10. The display device of claim 1 , wherein the light-emitting element is a turned-on state in at least a part of the first period and the second period, and is a turned-off state in the third period.
11. The display device of claim 1 , wherein the sensing line is floated in the second period.
12. The display device of claim 1 , wherein the sensing transistor maintains a turned-on state during the sensing period.
13. The display device of claim 1 , wherein the each of the plurality of subpixels further comprises a switching transistor electrically connected to a gate node of the driving transistor, and
the switching transistor is a turned-on state during a period that the sensing transistor is a turned-on state.
14. The display device of claim 1 , wherein the initialization voltage is greater than a threshold voltage of the light-emitting element.
15. The display device of claim 1 , wherein the sensing voltage is simultaneously detected from two or more subpixels electrically connected to the sensing line among the plurality of subpixels, a compensation voltage configured based on the sensing voltage is supplied to the two or more subpixels, and
the compensation voltage supplied to a first subpixel of the two or more subpixels is different from the compensation voltage supplied to a second subpixel of the two or more subpixels.
16. A display device, comprising:
a plurality of subpixels disposed in a display panel;
a plurality of sensing lines electrically connected to at least one of the plurality of subpixels; and
a driving circuit configured to drive the plurality of sensing lines,
wherein each of the plurality of subpixels comprises,
a light-emitting element;
a driving transistor configured to drive the light-emitting element; and
a sensing transistor electrically connected between a sensing node which the light-emitting element and the driving transistor are electrically connected to each other and the sensing line,
wherein the display device is configured in that, during a sensing period for detecting a characteristic value of the light-emitting element,
an initialization voltage is supplied to the sensing node and a sensing voltage of the sensing node is detected after a predetermined period,
the driving transistor is a turned-off state in at least a part period of the sensing period, and
the driving transistor is a turned-off state when the sensing voltage of the sensing node is detected.
17. The display device of claim 16 , wherein the driving transistor becomes a turned-on state in a part period of the predetermined period.
18. The display device of claim 17 , wherein the driving transistor becomes a turned-off state before the sensing voltage of the sensing node is detected.
19. The display device of claim 17 , wherein the light-emitting element is a turned-off state in a period that the driving transistor is a turned-on state.
20. A driving circuit, comprising:
a driving circuit configured to:
control a voltage output to a data line electrically connected to a subpixel; and
control a voltage output to a sensing line electrically connected to the subpixel,
wherein the driving circuit is electrically connected to the sensing line,
wherein, during a sensing period for detecting a characteristic value of a light-emitting element disposed on the subpixel,
in a first period, the driving circuit is configured to output a sensing data voltage to the data line, and to output an initialization voltage to the sensing line,
in a second period, the driving circuit is configured to stop an output of the initialization voltage,
in a third period, the driving circuit is configured to output an auxiliary data voltage greater than the sensing data voltage and smaller than the initialization voltage to the data line, and
in a fourth period, the driving circuit is configured to detect a sensing voltage through the sensing line.