Patent ID: 6094081
Filing Date: 2000-07-25
Classification: H03K,H03L

Abstract:
A digital controlled oscillation circuit in which the oscillation frequency is controlled in accordance with a control signal, comprising:a first delay circuit for delaying a first signal by exactly a delay time set by the control signal and outputting the same as a first delay signal;a second delay circuit for delaying a second signal by exactly the delay time set by the control signal and outputting the same as a second delay signal;an output signal generation circuit which switches a first output signal from a first level to a second level and outputs the same and, switches a second output signal from the second level to the first level and outputs the same when receiving the first delay signal, while switches the first output signal from the second level to the first level and outputs the same and, switches the second output signal from the first level to the second level and outputs the same when receiving the second delay signal;a first switching detection circuit for generating the first signal and outputting the same to the first delay circuit when detecting that the first output signal is switched from the second level to the first level; anda second switching detection circuit for generating the second signal and outputting the same to the second delay circuit when detecting that the second output signal is switched from the second level to the first level.