Renesas Electronics Corporation

Takeshi Oshita

Takanori Hirota

Masato Suzuki

Atsuhiko Ishibashi

Masashi Ishii

Yasushi Hayakawa

Yoshiyuki Ota

A delay time is set only within the variable delay time of a clock driver and cannot be set longer than the variable delay time of the clock driver. A control circuit adjusts the delay amount of a variable delay circuit so as to synchronize a pulse phase after a first pulse outputted from a pulse generation circuit passes through the variable delay circuit N times and a second pulse outputted from the pulse generation circuit.

Semiconductor device

A phase comparison circuit detects a phase difference between a data signal and the output from a variable delay circuit. A Code Operator detects a value of a control code corresponding to a delay equal to one period of an output clock. Then, when a delay amount of the variable delay circuit exceeds one period of a clock during synchronization of the output clock with the data signal while the control code is changed in accordance with the detection result by the phase delay circuit, a control code corresponding to a delay equal to one period of the output clock is added or subtracted to/from the control code at a time. Therefore, even if there is a difference in frequency between a data signal and a clock, it becomes possible to synchronize the data signal and the clock with application of the same clock phase.

Clock data recovery circuit capable of generating clock signal synchronized with data signal

Growing community of inventors

Tokyo, Japan

Takeshi Oshita