Display device and driving method thereof

1. A display device comprising:

a processor supplying grayscale data in active periods of frame periods and stopping supply of the grayscale data in blank periods of the frame periods;

a switch controller generating a first switch control signal when a blank period is longer than a predetermined period, and generating a second switch control signal when the blank period ends;

a power supply supplying a voltage different from a first power voltage to a first power line when the first switch control signal is received and supplying the first power voltage to the first power line when the second switch control signal is received; and

pixels commonly connected to the first power line,

wherein lengths of the active periods of the frame periods are equal to each other,

wherein at least two of the blank periods of the frame periods have different lengths,

wherein the blank periods include a first blank period and a second blank period,

wherein the first power line maintains the first power voltage during the first blank period,

wherein the first power line maintains the first power voltage during a first period of the second blank period, and the first power line maintains the voltage different from the first power voltage during a second period of the second blank period, and

wherein the first period is longer than the first blank period.

2. The display device of claim 1 , wherein the power supply supplies a second power voltage lower than the first power voltage to the first power line when the first switch control signal is received, and wherein the pixels are commonly connected to a second power line to which the second power voltage is applied.

3. The display device of claim 2 , wherein the first power voltage is greater than the second power voltage.

4. The display device of claim 2 , wherein the power supply includes:

a first power source generating the first power voltage;

a second power source generating the second power voltage; and

a switch connecting the first power line to the second power line when the first switch control signal is received, and connecting the first power line to the first power source when the second switch control signal is received.

5. The display device of claim 1 , wherein the power supply supplies a reference voltage lower than the first power voltage to the first power line when the first switch control signal is received,

Wherein the pixels are commonly connected to a second power line to which a second power voltage is applied, and

wherein the reference voltage is different from the first power voltage and the second power voltage.

6. The display device of claim 5 , wherein the first power voltage is greater than the reference voltage.

7. The display device of claim 5 , wherein the power supply includes:

a first power source generating the first power voltage;

a second power source generating the second power voltage; and

a switch applying the reference voltage to the first power line when the first switch control signal is received, and connecting the first power line to the first power source when the second switch control signal is received.

8. The display device of claim 1 , wherein the blank periods further include a third blank period,

wherein the first power line maintains the first power voltage during a third period of the third blank period, and the first power line maintains the voltage different from the first power voltage during a fourth period of the third blank period,

wherein lengths of the third period and the first period are equal to each other, and

wherein the fourth period is longer than the second period.

9. The display device of claim 8 , wherein the pixels are in a non-emission state during the second period and the fourth period.

10. A display device comprising:

a processor supplying grayscale data in active periods of frame periods and stopping supply of the grayscale data in blank periods of the frame periods;

a switch controller generating a first switch control signal when a blank period is longer than a predetermined period, and generating a second switch control signal when the blank period ends;

a power supply supplying a voltage different from a first power voltage to a first power line when the first switch control signal is received and supplying the first power voltage to the first power line when the second switch control signal is received; and

pixels commonly connected to the first power line,

wherein the switch controller includes:

a counter generating a low frequency detection signal when the blank period is longer than the predetermined period; and

a switch control signal generator generating the first switch control signal when the low frequency detection signal is received and generating the second switch control signal when a scan start signal is received.

11. The display device of claim 10 , wherein the counter generates the low frequency detection signal when a data enable signal having a disable level is longer than the predetermined period.

12. The display device of claim 10 , wherein the counter generates the low frequency detection signal when a vertical synchronization signal having a disabled level is longer than the predetermined period.

13. The display device of claim 10 , further comprising:

a scan driver sequentially providing scan signals of a turn-on level to scan lines connected to the pixels when the scan start signal is received.

14. A driving method of a display device comprising:

supplying grayscale data in an active period of a frame period and stopping supply of the grayscale data in a blank period of the frame period by a processor;

generating a first switch control signal by a switch controller when the blank period is longer than a predetermined period;

supplying a voltage different from a first power voltage to a first power line by a power supply when the first switch control signal is received;

receiving the voltage different from the first power voltage by pixels commonly connected to the first power line;

generating a second switch control signal by the switch controller when the blank period ends;

supplying the first power voltage to the first power line by the power supply when the second switch control signal is received; and

receiving the first power voltage by the pixels,

wherein the processor supplies the grayscale data in active periods of frame periods and stops supply of the grayscale data in blank periods of the frame periods,

wherein lengths of the active periods are equal to each other,

wherein at least two of the blank periods have different lengths,

wherein the blank periods include a first blank period and a second blank period,

wherein the first power line maintains the first power voltage during the first blank period,

wherein the first power line maintains the first power voltage during a first period of the second blank period, and the first power line maintains the voltage different from the first power voltage during a second period of the second blank period, and

wherein the first period is longer than the first blank period.

15. The driving method of claim 14 , wherein the blank periods further include a third blank period,

wherein the first power line maintains the first power voltage during a third period of the third blank period, and the first power line maintains the voltage different from the first power voltage during a fourth period of the third blank period,

wherein lengths of the third period and the first period are equal to each other, and

wherein the fourth period is longer than the second period.

16. The driving method of claim 15 , wherein the pixels are in a non-emission state during the second period and the fourth period.