LOW FREQUENCY DETECTING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To output a negative delay signal corresponding to the frequency of a clock signal input from the outside without increasing the circuit scale and complicating the circuit. SOLUTION: This low frequency detecting circuit includes a negative delay signal generating part 100 adapted to receive an input signal CK and output a negative delay signal CK1 and low frequency detecting signals NDAS1-NDAS7, a low frequency detecting part 101 adapted to receive a low frequency detecting signal NDAS1-NDAS7 and output a flag signal SF, and a signal select part 102 for selecting either the input signal CK or the load delay signal CK and outputting the same according to the flag signal SF.