摘要 |
It is an object of the present invention to improve the phase difference detection accuracy of a phase comparator. A phase difference signal generation circuit outputs a signal C_SIGNAL which takes a high level for a period corresponding to the phase difference between the comparison target signals COMP1 and COMP2 to the control terminal of a tri-state buffer, based on a signal synchronous with the start-up of the comparison target signal COMP1 detected by an edge detection flag generation circuit and a signal synchronous with the start-up of the comparison target signal COMP2 detected by an edge detection flag generation circuit. A status management circuit outputs a signal A_SIGNAL corresponding to the phase advance or delay of the comparison target signals COMP1 and COMP2 to the input terminal of the tri-state buffer. |