Image device and operating method thereof

1. An image device, comprising:

a clock generator to generate a first output clock of a first frequency;

a link layer circuit to generate a control signal for changing the first frequency and output first parallel data including first frame information;

a detector to generate a collision avoidance command to change the first frequency to a second frequency during a vertical blanking time, the second frequency being different from the first frequency; and

a frequency changing circuit to receive the collision avoidance command from the detector and transmit a frequency change command to the link layer circuit, wherein:

the link layer circuit transmits the control signal to the clock generator based on the frequency change command, and

the vertical blanking time is a time period from a first time point at which the first parallel data is not output from the link layer circuit to a second time point at which second parallel data is output, the second parallel data including second frame information subsequent to the first frame information.

2. The image device as claimed in claim 1 , wherein

the clock generator includes a phase-locked loop (PLL) circuit and a clock gating circuit, and wherein:

the PLL circuit generates a first PLL clock of the first frequency, and

the clock gating circuit generates the first output clock by controlling output of the first PLL clock.

3. The image device as claimed in claim 2 , wherein

the control signal includes a frequency division control signal and a clock enable signal, and wherein:

the frequency division control signal changes the first frequency of the first PLL clock to the second frequency, and

when the clock enable signal is deactivated, the first PLL clock is blocked by the clock gating circuit such that the first output clock is not output.

4. The image device as claimed in claim 3 , wherein the clock gating circuit includes an inverter, a selector, a first flip-flop, and a second flip-flop, wherein:

the inverter receives the first PLL clock and outputs an inverted first PLL clock,

the first flip-flop receives the clock enable signal via a first input terminal of the first flip-flop and receives the inverted first PLL clock via a second input terminal of the first flip-flop,

the second flip-flop includes a third input terminal connected to a first output terminal of the first flip-flop, receives the inverted first PLL clock via a fourth input terminal of the second flip-flop, and outputs a selection signal via a third output terminal of the second flip-flop, and

the selector receives the first PLL clock via a first input selection terminal of the selector, receives a ground voltage via a second input selection terminal of the selector, selects one of the first PLL clock and the ground voltage, and outputs the selected one as the first output clock.

5. The image device as claimed in claim 3 , wherein:

the clock enable signal is deactivated at the second time point when is later than the first time point by a first period,

the frequency division control signal changes the first frequency of the first PLL clock at a third time point when is later than the second time point by a second period, and

the clock enable signal is activated at a fourth time point when is later than the third time point by a third period.

6. The image device as claimed in claim 5 , wherein:

the link layer circuit is operated based on a first word clock, and

the first period is thirty times of a clock cycle of the first word clock.

7. The image device as claimed in claim 5 , wherein the third period is 75 microseconds or more.

8. The image device as claimed in claim 1 , further comprising a first peripheral circuit to operate in a first bandwidth, wherein

the detector senses whether there is frequency collision between the first frequency and the first bandwidth and transmits the collision avoidance command to the frequency changing circuit when the frequency collision is sensed.

9. The image device as claimed in claim 8 , wherein the second frequency does not collide with the first bandwidth.

10. An image device, comprising:

a detector to generate a collision avoidance command;

a frequency changing circuit to receive the collision avoidance command from the detector and generate a frequency change command;

a link layer circuit to receive the frequency change command from the frequency changing circuit, generate a control signal based on the frequency change command, and output first parallel data including first frame information; and

a clock generator to receive the control signal from the link layer circuit and generate a first output clock of a first frequency, wherein:

the first frequency is changed to a second frequency during a vertical blanking time, the second frequency being different from the first frequency, and

the vertical blanking time is a time period from a first time point at which the first parallel data is not output from the link layer circuit to a second time point at which second parallel data is output, the second parallel data including second frame information subsequent to the first frame information.

11. The image device as claimed in claim 10 , wherein

the clock generator includes a phase-locked loop (PLL) circuit and a clock gating circuit, wherein:

the PLL circuit generates a first PLL clock of the first frequency,

the clock gating circuit generates the first output clock by controlling output of the first PLL clock, and

the control signal includes a frequency division control signal and a clock enable signal, and wherein:

the frequency division control signal changes the first frequency of the first PLL clock, and

when the clock enable signal is deactivated, the first PLL clock is blocked by the clock gating circuit such that the first output clock is not output.

12. The image device as claimed in claim 11 , wherein the clock gating circuit includes an inverter, a selector, a first flip-flop, and a second flip-flop, and wherein:

the inverter receives the first PLL clock and outputs an inverted first PLL clock,

the first flip-flop receives the clock enable signal via a first input terminal of the first flip-flop and receives the inverted first PLL clock via a second input terminal of the first flip-flop,

the second flip-flop includes a third input terminal connected to a first output terminal of the first flip-flop, receives the inverted first PLL clock via a fourth input terminal of the second flip-flop, and outputs a selection signal via a third output terminal of the second flip-flop, and

the selector receives the first PLL clock via a first input selection terminal, receives a ground voltage via a second input selection terminal of the selector, and selects one of the first PLL clock and the ground voltage, and outputs the selected one as the first output clock.

13. The image device as claimed in claim 11 , wherein the clock enable signal is deactivated at a second time point when is later than the first time point by a first period, and

the frequency division control signal changes the first frequency of the first PLL clock at a third time point when is later than the second time point by a second period, and

the clock enable signal is activated at a fourth time point when is later than the third time point by a third period.

14. The image device as claimed in claim 13 , wherein:

the link layer circuit is operated based on a first word clock, and

the first period is thirty times of a clock cycle of the first word clock.

15. The image device as claimed in claim 13 , wherein the third period is 75 microseconds or more.

16. The image device as claimed in claim 10 , further comprising a first peripheral circuit to operate at a first bandwidth, wherein:

the detector senses whether there is frequency collision between the first frequency and the first bandwidth, and transmits the collision avoidance command to the frequency changing circuit when the frequency collision is sensed, and

the second frequency does not collide with the first bandwidth.

17. An image device, comprising:

a link layer circuit to generate first parallel data including first frame information, the first parallel data being not generated from a first time point;

a first peripheral circuit to operate at a first bandwidth;

a clock generator to generate a first output clock of a first frequency;

a detector to sense whether there is frequency collision between the first bandwidth and the first frequency and generate a collision avoidance command when the frequency collision is sensed; and

a frequency changing circuit to receive the collision avoidance command from the detector and generate a frequency change command to change the first frequency to a second frequency after the first time point, the second frequency not colliding with the first bandwidth.

18. The image device as claimed in claim 17 , wherein the clock generator includes a phase-locked loop (PLL) circuit and a clock gating circuit, wherein:

the PLL circuit generates a first PLL clock operating at the first frequency,

the clock gating circuit generates the first output clock by controlling output of the first PLL clock, and

the link layer circuit generates a control signal, the control signal including a frequency division control signal and a clock enable signal, wherein:

when the clock enable signal is deactivated, the first PLL clock is blocked by the clock gating circuit such that the first output clock is not output at a second time point when is later than the first time point by a first period, and

the frequency division control signal changes the first frequency of the first PLL clock to the second frequency at a third time point when is later than the second time point by a second period.

19. The image device as claimed in claim 18 , wherein:

the link layer circuit is operated based on a first word clock,

the first period is thirty times of a clock cycle of the first word clock,

the clock enable signal is activated at a fourth time point when is later than the third time point by a third period, and

the third period is 75 microseconds or more.

20. The image device as claimed in claim 17 , further comprising a first peripheral circuit to operate in a first bandwidth, wherein:

the detector senses whether there is frequency collision between the first frequency and the first bandwidth and transmits the collision avoidance command to the frequency changing circuit when the frequency collision is sensed,

the second frequency does not collide with the first bandwidth,

the clock generator includes a phase-locked loop (PLL) circuit and a clock gating circuit, and wherein:

the PLL circuit generates a first PLL clock operating at the first frequency,

the clock gating circuit generates the first output clock by controlling the first PLL clock,

the link layer circuit generates a control signal, the control signal including a frequency division control signal and a clock enable signal,

the clock enable signal is deactivated, the first PLL clock is blocked by the clock gating circuit such that the first output clock is not output at a second time point when is later than the first time point by a first period, and

the frequency division control signal changes the first frequency of the first PLL clock to the second frequency at a third time point when is later than the second time point by a second period.