| 摘要 |
PROBLEM TO BE SOLVED: To change momentarily a frequency of an output signal by changing a frequency of a global clock signal in response to a control signal and keeping a feedback clock signal to be a prescribed frequency at the same time. SOLUTION: A feedback clock signal FBCLK is generated by a feedback control loop consisting of a phase clock circuit 210 and a frequency converter 200a. The circuit 210 compares the signal FBCLK with a reference clock signal RCLK to apply proper adjustment to a PLL clock signal PLLCLK generated by an output node 215. Furthermore, the circuit 210 generates a 1st clock signal in response to the signals RCLK, FBCLK and generates a global clock signal GCLK in response thereto. A converter 200a changes he frequency of the signal GCLK in response to the control signal and keeps the signal FBCLK to be a constant frequency. Then the phase or frequency deviation between the signals RCLK, FBCLK is corrected to realize the synchronization. |
