The present invention discloses a clock data recovery method having quick locking and bandwidth stabilizing mechanism used in a clock data recovery circuit. A relative position relation between a serial data and a sampling clock is detected by a phase detection circuit in an adaptive control period to generate a tracking direction. The tracking direction of a first clock period is directly outputted as an adaptive tracking direction by an adaptive tracking circuit. For each of the clock periods behind the first clock period, a previous tracking direction is replaced by a current tracking direction only when the current tracking direction exists and is different from the previous tracking direction of a previous clock period such that an actual tracking direction is generated when the adaptive tracking direction changes. The phase of the sampling clock is adjusted according to the actual tracking direction by a clock control circuit.

A frequency-locked loop (FLL) logic circuit, including a validity signal generator configured to receive an external clock signal and determine whether a glitch occurs in the external clock signal; a clock divider configured to generate a reference frequency clock signal based on the external clock signal and a determination result of the validity signal generator; a synchronizer configured to synchronize a phase of an oscillator clock signal with a phase of the reference frequency clock signal; a clock counter configured to count a number of pulses of the oscillator clock signal during a reference time; and a code limiter configured to determine a range of a frequency selection value for calibrating an operating frequency of the oscillator clock signal based on the counted number of pulses.

A frequency-locked loop (FLL) logic circuit, including a validity signal generator configured to receive an external clock signal and determine whether a glitch occurs in the external clock signal; a clock divider configured to generate a reference frequency clock signal based on the external clock signal and a determination result of the validity signal generator; a synchronizer configured to synchronize a phase of an oscillator clock signal with a phase of the reference frequency clock signal; a clock counter configured to count a number of pulses of the oscillator clock signal during a reference time; and a code limiter configured to determine a range of a frequency selection value for calibrating an operating frequency of the oscillator clock signal based on the counted number of pulses.

A phase-locked loop (PLL) circuit generates an analog signal in phase-lock with a reference signal at a reference frequency. The PLL circuit includes a charge pump circuit, a loop filter circuit, a feedback divider, and a voltage controlled oscillator (VCO). The charge pump circuit charges a sample capacitor of the loop filter circuit to a sample voltage based on a phase difference between the generated analog signal and the reference signal. The loop filter circuit stores the sample voltage as a proportional control voltage in a hold capacitor to reduce or avoid ripple in the control voltage that causes jitter in the analog signal. The loop filter circuit also provides the sample voltage to an integral component circuit comprising a comparator and digital accumulator producing an integral control. The VCO generates the analog signal at a frequency based on the proportional control voltage and the integral control voltage.

A phase-locked loop (PLL) circuit generates an analog signal in phase-lock with a reference signal at a reference frequency. The PLL circuit includes a charge pump circuit, a loop filter circuit, a feedback divider, and a voltage controlled oscillator (VCO). The charge pump circuit charges a sample capacitor of the loop filter circuit to a sample voltage based on a phase difference between the generated analog signal and the reference signal. The loop filter circuit stores the sample voltage as a proportional control voltage in a hold capacitor to reduce or avoid ripple in the control voltage that causes jitter in the analog signal. The loop filter circuit also provides the sample voltage to an integral component circuit comprising a comparator and digital accumulator producing an integral control. The VCO generates the analog signal at a frequency based on the proportional control voltage and the integral control voltage.

An apparatus includes a sampling circuit, a sense circuit, and a tuning circuit. The sampling circuit samples an input signal according to a sampling clock signal to produce a sampled signal. The sense circuit determines a scaling factor based on a distortion in the sampled signal caused by the sampling clock signal. The tuning circuit generates an offset signal based on the sampling clock signal and the scaling factor. The offset signal reduces the distortion in the sampled signal caused by the sampling clock signal.

An apparatus includes a sampling circuit, a sense circuit, and a tuning circuit. The sampling circuit samples an input signal according to a sampling clock signal to produce a sampled signal. The sense circuit determines a scaling factor based on a distortion in the sampled signal caused by the sampling clock signal. The tuning circuit generates an offset signal based on the sampling clock signal and the scaling factor. The offset signal reduces the distortion in the sampled signal caused by the sampling clock signal.

An electronic device includes a dock dividing circuit configured to generate sampling clocks, alignment clocks and output clocks by dividing a frequency of a write clock; and a data alignment circuit configured to, in a first operation mode, receive input data having any one level among a first level to a fourth level and generate alignment data by aligning the input data in synchronization with the sampling clocks, the alignment clocks and the output clocks, and to, in a second operation mode, receive the input data having any one level of the first level and the fourth level and generate the alignment data by aligning the input data in synchronization with the sampling clocks, the alignment clocks and the output clocks.

An electronic device includes a dock dividing circuit configured to generate sampling clocks, alignment clocks and output clocks by dividing a frequency of a write clock; and a data alignment circuit configured to, in a first operation mode, receive input data having any one level among a first level to a fourth level and generate alignment data by aligning the input data in synchronization with the sampling clocks, the alignment clocks and the output clocks, and to, in a second operation mode, receive the input data having any one level of the first level and the fourth level and generate the alignment data by aligning the input data in synchronization with the sampling clocks, the alignment clocks and the output clocks.

Various implementations described herein are directed to a device with a voltage-controlled oscillator that receives an enable signal, receives a reset signal, and provides internal pulse signals including one or more coarse internal pulse signals and multiple fine internal pulse signals. The device may have a coarse sampler that receives the one or more coarse internal pulse signal and provides a coarse sampled output signal. The device may have a fine sampler that receives the multiple fine internal pulse signals and provides a fine sampled output signal.