Apparatuses and methods of DLL measurement initialization are disclosed. An example apparatus includes: a clock enable circuit that provides a first clock signal having a half frequency of an input clock signal and second clock signals having a quarter frequency of the input clock signal; a coarse delay that provides the first clock signal with a coarse delay; a fine delay that provides the first clock signal with the coarse delay and a fine delay as an output clock signal; a model delay having a feedback delay equivalent to a sum of delays of an input stage and an output stage, and provides a feedback signal that is the output clock signal with the feedback delay; and a measurement initialization circuit that performs measurement initialization. The measurement initialization circuit includes synchronizers that receive the feedback signal and the second clock signals, and provide a stop signal to the coarse delay.

A clock generation circuit may include a clock receiver, a first delay loop circuit, and a second delay loop circuit. The clock receiver may receive a first clock signal and a second clock signal and generate a first reception clock signal and a second reception clock signal. The first delay loop circuit may receive the first reception clock signal and the second reception clock signal generate a reference clock signal. The first delay loop circuit may perform a delay-locking operation on the reference clock signal to generate a first delay locked clock signal. The second delay loop circuit may delay the first reception clock signal and the second reception clock signal based on the first delay locked clock signal and an internal clock signal to generate a first internal clock signal.

A pulse signal generation circuit includes a clock frequency division component, a time delay component and a selection component. The clock frequency division component is configured to perform frequency division on a clock signal to generate a clock frequency division signal; the time delay component is configured to generate a time delay signal based on the clock frequency division signal; and the selection component is configured to receive the clock frequency division signal and the time delay signal at the same time, and select the clock frequency division signal and the time delay signal according to a preset condition to generate a pulse signal.

A time measurement device for calculating a time from an input of a first trigger signal to an input of a second trigger signal as a measured time includes a start gate configured to generate a start signal, a stop gate configured to generate a stop signal, a TDC circuit configured to generate a digital code corresponding to the time from an input of a start signal to an input of a stop signal, a delay circuit configured to delay an input of at least one of the start signal and the stop signal to the TDC circuit by a predetermined delay time, and a control unit configured to calculate a measured time on the basis of a plurality of digital codes generated by the TDC circuit, wherein the time delay unit selects at least two delay times.

Digital delay locked loop circuits, devices systems, and associated methods are provided and described. Such devices, systems, and methods utilize an open loop measurement for establishing a coarse delay lock.

A delay locked loop circuit includes: a variable delay line configured to delay an initial clock signal to generate a delayed clock signal; and a control circuit connected to the variable delay line, configured to control the variable delay line to perform delay adjustment of a first mode and further configured to perform delay adjustment of a second mode on the variable delay line when the delayed clock signal satisfies a preset condition. A step value of each delay adjustment of the first mode is a first step value, a step value of each delay adjustment of the second mode is a second step value, and the second step value is greater than the first step value.

A delay locked loop operates over a wide range of frequencies and has high accuracy, small silicon area usage, low power consumption and a short lock time. The DLL combines an analog domain and a digital domain. The digital domain is responsible for initial lock and operational point stability and is frozen after the lock is reached. The analog domain is responsible for normal operation after lock is reached and provides high accuracy using smaller silicon area and low power.

According to one embodiment, a synchronous semiconductor device is disclosed According to this embodiment, the synchronous semiconductor device includes a pulse width detection circuit to determine whether at least one of a plurality of delay step sizes is less than at least one of a high pulse width and a low pulse width of a first clock signal and to select one of the delay step sizes and a delay line to delay the first clock signal to produce as second clock signal by a first delay amount that is changed based at least on the one of the delay step sizes.

A delay locked loop circuit includes: a variable delay line configured to delay an initial clock signal to generate a delayed clock signal; and a control circuit connected to the variable delay line, configured to control the variable delay line to perform delay adjustment of a first mode and further configured to perform delay adjustment of a second mode on the variable delay line when the delayed clock signal satisfies a preset condition. A step value of each delay adjustment of the first mode is a first step value, a step value of each delay adjustment of the second mode is a second step value, and the second step value is greater than the first step value.

Digital delay lock circuits and methods for operating digital delay lock circuits are provided. A phase detector is configured to receive first and second clock signals and generate a digital signal indicating a relationship between a phase of the first clock signal and a phase of the second clock signal. A phase accumulator circuit is configured to receive the digital signal and generate a phase signal based on values of the digital signal over multiple clock cycles. A decoder is configured to receive the phase signal and generate a digital control word based on the phase signal. A delay element is configured to receive the digital control word. The delay element is further configured to change the relationship between the phase of the first clock signal and the phase of the second clock signal by modifying the phase of the second clock signal according to the digital control word.