A phase locked loop device may include: a frequency modulating circuit configured to output a reference signal obtained by multiplying a frequency of an input signal by a predetermined ratio based on the input signal; a sigma-delta modulator configured to output division ratio information on one of a plurality of division rates at a number of times proportional to a frequency of the reference signal; and a phase locked loop (PLL) circuit configured to determine whether to activate based on a command signal, and, when activated, perform a phase-locking operation based on a fractional division based on the reference signal and the division ratio information.

A DTC circuit, includes: a DAC connected to a first node; a first switch connected between a first power source and a second node, and to provide a charge current to the second node according to a first switching signal; and a second switch connected between the first node and the second node, and to electrically connect the DAC to the second node according to a second switching signal. The DAC is to be charged to generate a voltage ramp corresponding to the charge current during a first DTC operational phase when the first and second switching signals have an active level to turn on the first and second switches, and to generate an input control word dependent voltage according to an input control word during a second DTC operational phase when the first and second switching signals have an inactive level to turn off the first and second switches.

Disclosed is an open loop fractional frequency divider including an integer divider, a control circuit, and a phase interpolator. The integer divider processes an input clock according to the setting of a target frequency to generate a first frequency-divided clock and a second frequency-divided clock. The control circuit generates a coarse-tune control signal and a fine-tune control signal according to the setting. The phase interpolator generates an output clock according to the first frequency-divided clock, the second frequency-divided clock, and the two control signals. The two control signals are used for determining a first current, and their reversed signals are used for determining a second current. The phase interpolator controls a contribution of the first (second) frequency-divided clock to the generation of the output clock according to the first (second) frequency-divided clock, the reversed signal of the first (second) frequency-divided clock, and the first (second) current.

A digital phase-frequency detector characterizes a delay between two input clock signals using a ring oscillator. A cycle count of a ring oscillator signal circulating through a loop in the ring oscillator during the delay provides a coarse measurement of the delay. A phase of the ring oscillator signal in the loop at the end of the delay provides a fine measurement of the delay. A digital phase-locked loop may control an oscillation frequency of a digitally-controlled oscillator responsive to the fine measurement of the delay and control a division within a clock divider responsive to the coarse measurement of the delay.

A calibration scheme is used to control PLL bandwidth and contain its spread. In open loop, the VCO control voltage is swept over a range of values and VCO output frequency is measured at each control voltage level. The gain KVCO is determined for each measured output frequency and a corresponding current magnitude for the variable magnitude charge pump is calculated from a ratio of a constant to the gain KVCO and correlated in a look-up table to the measured output frequency. Once calibration is completed, the PLL loop is closed and a calculated current magnitude is fetched from the look-up table based on a desired output frequency for the PLL circuit. The variable magnitude charge pump circuit is then controlled to generate a charge pump current with a magnitude corresponding to the fetched charge pump current magnitude.

A phase and frequency detector receives a reference clock signal with a period error and receives a feedback clock signal from a feedback divider. The feedback divider circuit divides a clock signal from a voltage controlled oscillator. The feedback divider divides by different divide values during odd and even cycles of the reference clock signal to cause the feedback clock signal to have a period error that substantially matches the period error of the reference clock signal. The divider values supplied to the feedback divider are determined, at least in part, by the period error of the reference clock signal.

A semiconductor device may include a programmable fabric and a processor. The processor may utilize one or more extension architectures. At least one of these extension architectures may be used to integrate and/or embed the programmable fabric into the processor as part of the processor. Systems and methods for transitioning data between the programmable fabric and the processor associated with different clock domains is described.

[Problem to be Solved] To provide a serial data transmission device that makes it possible to dynamically switch a band or a data transmission path and enhance the stability to failure while multiplexing and transmitting data by a TDM method when serial data is transmitted between a plurality of daisy-chained data transmission devices. [Solution] There is provided a serial data transmission device including: a receiver that receives data serially transmitted by a time-division multiplex method from another device daisy-chained to the serial data transmission device; a transmitter that serially transmits data by the time-division multiplex method to another device daisy-chained to the serial data transmission device; and a controller that controls serial transmission by the receiver and the transmitter, in which the controller performs control to make the serial transmission by the transmitter adjustable.

A signal generator includes a first phase-locked loop (PLL) configured to receive a first reference signal having a first reference frequency and generate a ramping signal based on the first reference signal, where the ramping signal is between a minimum frequency and a maximum frequency of a radar frequency band; a system clock configured to generate a second reference signal having a common system reference frequency; and a second PLL configured to receive the second reference signal from the system clock, generate the first reference signal based on the second reference signal, and provide the first reference signal to the first PLL.

Disclosed is an open loop fractional frequency divider including an integer divider, a control circuit, and a phase interpolator. The integer divider processes an input clock according to the setting of a target frequency to generate a first frequency-divided clock and a second frequency-divided clock. The control circuit generates a coarse-tune control signal and a fine-tune control signal according to the setting. The phase interpolator generates an output clock according to the first frequency-divided clock, the second frequency-divided clock, and the two control signals. The two control signals are used for determining a first current, and their reversed signals are used for determining a second current. The phase interpolator controls a contribution of the first (second) frequency-divided clock to the generation of the output clock according to the first (second) frequency-divided clock, the reversed signal of the first (second) frequency-divided clock, and the first (second) current.