The disclosure provides a signal synchronizing device and a digital signal output device. A digital circuit counts a first frequency signal to generate a count value, and generates an output voltage according to the count value. An analog circuit generates a feedback signal according to the output voltage. A synchronization circuit samples the feedback signal according to a second frequency signal to generate a synchronization signal. A control circuit generates a voltage control signal according to the second frequency signal and the synchronization signal to control the digital circuit to stop counting the first frequency signal, and a frequency of the first frequency signal is lower than a frequency of the second frequency signal.

An oscillator including a switched capacitor configured to generate a sawtooth or ramp voltage in response to a switched capacitor drive signal; a low pass filter (LPF) configured to filter the sawtooth or ramp voltage to generate a filtered voltage; a reference voltage generator configured to generate a reference voltage; an integrator configured to integrate a difference between the sawtooth or ramp voltage and the reference voltage to generate a frequency control signal; a voltage controlled oscillator (VCO) configured to generate a first clock based on the frequency control signal; a frequency divider configured to frequency divide the first clock to generate a second clock; and a switched capacitor driver configured to generate the switched capacitor drive signal in response to the second clock. The oscillator may also include a switched capacitor sampler to sample the sawtooth or ramp voltage, wherein the filtered voltage is based on the sampled voltage.

An apparatus includes a first function module providing a master signal, a second function module providing a comparison signal, and safety logic. The safety logic includes a toggle signal generator having a comparator providing a comparison result in response to the master signal and the comparison signal, a feedback path generating a first toggle signal in response to the comparison result and providing a feedback signal to the comparator, and a first multiple input gate generating a second toggle signal in response to the comparison result. The safety logic also includes a toggle signal monitor providing a final fault search signal in response to the first toggle signal and the second toggle signal.

A system and method to dynamically control a reset signal for an IQ divider are provided. The system includes an IQ divider configured to output a IQ divider output clock; an input configured to receive a reference clock; a failure sensing circuit configured to sense a failure in the IQ divider output clock, the failure sensing circuit including an automatic frequency calibration (AFC) logic; and a control circuit configured to control a reset signal provided to the IQ divider, based on an output of the failure sensing circuit corresponding the failure sensed by the failure sensing circuit.

An apparatus includes a digitally controlled oscillator (DCO), which includes an inductor coupled in series with a first capacitor. The DCO further includes a second capacitor coupled in parallel with the series-coupled inductor and first capacitor, a first inverter coupled in parallel with the second capacitor, and a second inverter coupled back-to-back to the first inverter. The DCO further includes a digital-to-analog-converter (DAC) to vary a capacitance of the first capacitor.

The application discloses a time-to-digital conversion circuit (100) including a first oscillator (110), a second oscillator (120), a first counting circuit (130), a second counting circuit (140), a first conversion circuit (150) and a processing circuit (160). The first oscillator is activated by a first signal and includes oscillating units having a first delay amount, wherein the first counting circuit is configured to count a number of times that the first tail end output signal of the first oscillator changes and store the same as a first counting result; the second counting circuit counts a number of oscillating units with an output change, other than the first tail end oscillating unit and stores the same as a second counting result; the first conversion circuit generates a first conversion signal according to the first counting result and the second counting result; the processing circuit generates the output signal at least according to the first conversion signal.

Both before and after a surprise clock stop, the apparatus and method of various embodiments supplies a stable and continuous clock to a memory module with a unique arrangement of circuit components, including a clock detector circuit, a clock-smoothing circuit, and one or more PLLs. Upon detection of a stopped host clock, a first PLL seamlessly switches to an alternate reference clock from an on-board crystal oscillator. A clock smoothing circuit allows the first PLL to maintain a steady phase and frequency without inducing glitches or period excursions greater than the natural jitter of the locked PLL; one or more optional downstream PLLs may drive additional clock domains.

Provided are a random number generating device and a method of operating the same. The random number generating device includes a source detector, a pulse generator, a counter, and a verification circuit. The source detector detects particles emitted from a source to generate a detection signal. The pulse generator generates pulses corresponding to the detected particles, based on the detection signal. The counter measures time intervals among the pulses and generates binary count values respectively corresponding to the time intervals. The verification circuit determines an output of the binary count values, based on the number of 0 values and the number of 1 values included in the binary count values.

A phase-locked loop (PLL) including a multiplexer with multiple inputs, each input coupled to receive a different reference clock. A time-to-digital converter (TDC) generates a TDC output value based on a phase difference between a reference clock from the multiplexer and a feedback clock. An averager circuit coupled to an output of the TDC. An adder circuit is coupled to outputs of the TDC and the averager circuit. A loop filter is coupled to an output of the adder circuit.

A phase-locked loop (PLL) including a multiplexer with multiple inputs, each input coupled to receive a different reference clock. A time-to-digital converter (TDC) generates a TDC output value based on a phase difference between a reference clock from the multiplexer and a feedback clock. An averager circuit coupled to an output of the TDC. An adder circuit is coupled to outputs of the TDC and the averager circuit. A loop filter is coupled to an output of the adder circuit.