A digital phase-locked loop (PLL) includes a time-to-digital converter (TDC) and a digitally controlled oscillator (DCO). The DCO generates a PLL clock signal and various sampling clock signals that are mesochronous. The TDC samples a phase difference between a reference clock signal and a frequency-divided version of the PLL clock signal based on the sampling clock signals and various enable signals. The enable signals are generated based on a calibration of the digital PLL. Each enable signal is associated with a sampling clock signal and indicates whether the associated sampling clock signal is to be utilized for sampling the phase difference. Further, the TDC generates control data indicative of the sampled phase difference. The DCO generates the PLL clock signal and the sampling clock signals based on the control data until the digital PLL is in a phase-locked state.

Disclosed herein is a tunable resonant circuit including an inductance directly electrically connected in series between first and second nodes, a variable capacitance directly electrically connected between the first and second nodes, and a set of switched capacitances coupled between the first and second nodes. The set of switched capacitances includes a plurality of capacitance units, each capacitance unit comprising a first capacitance for that capacitance unit directly electrically connected between the first node and a switch and a second capacitance for the capacitance unit directly electrically connected between the switch and the second node. Control circuitry is configured to receive an input control signal and connected to control the switches of the set of switched capacitances. A biasing circuit is directly electrically connected to the tunable resonance circuit at the first and second nodes.

In a PLL circuit, first an ILFD is connected to an output voltage Vtune from an LPF, thereby causing the ILFD to operate as an oscillator. The ILFD, a DIV, PFD, CP, and LPF form a PLL and thereby locking operations are initiated. When a predetermined time elapses, an output frequency from the ILFD converges into a certain value and the PLL is subjected to a locked state. After the locked state is reached, a sample hold circuit SH holds the output voltage Vtune from the loop filter as of that time and frequency adjustment of the ILFD is completed. Similar frequency adjustment is sequentially performed on other ILFDs.

A method for generating a clock signal using a digital phase-locked loop includes updating a gain of a variable gain digital filter of the digital phase-locked loop using an estimate error of a current estimate of a phase and a frequency of an input clock signal and a measurement error of a measurement of the phase and the frequency of the input clock signal. The gain may include a proportional gain component and an integral gain component. The method may include calculating the current estimate of the phase and the frequency of the input clock signal based on a previous estimate of the phase and the frequency of the input clock signal, the measurement of the phase and the frequency of the input clock signal, and the gain of the variable gain digital filter. The gain may be updated every cycle of the input clock signal.

An apparatus comprises a digitally controlled circuit having a variable capacitance and a controller configured to adjust a magnitude of the variable capacitance of the digitally controlled circuit. The digitally controlled circuit comprises a plurality of gain elements, the plurality of gain elements comprising one or more positive voltage-to-frequency gain elements and one or more negative voltage-to-frequency gain elements. The controller is configured to adjust the magnitude of the capacitance by adjusting the gain provided by respective ones of the gain elements in an alternating sequence of the positive voltage-to-frequency gain elements and the negative voltage-to-frequency gain elements.

A transmitter circuit in a wireless power transmission system has a tank circuit, having an inductor and a capacitor, the inductor being couplable to the inductor of a receiver circuit. An oscillator generates an oscillation frequency signal for driving the tank circuit. A first digital-to-analog converter (DAC) provides a first control signal to control the oscillating frequency of the oscillator. A frequency shift keying (FSK) circuit changes a digital signal input to the digital-to-analog converter for shifting the oscillation frequency utilized to drive the tank circuit, the FSK signal transmitting data or commands to the receiver circuit. A method of transmitting FSK signals in a wireless power transmission system is also disclosed.

To speed up output clock alignment in a digital phase locked loop wherein a controlled oscillator generates synthesizer pulses that are divided to produce output pulses at a predetermined normal spacing and time location, and wherein during an alignment procedure the output pulses are moved in time in response to a delay value obtained by comparing a phase of the output pulses with a phase applied to the controlled oscillator averaged over a number of synthesizer pulses in a feedback circuit to align said output pulses with a reference clock taking into account hardware delay, a group of the output pulses is advanced during the alignment procedure to reduce the spacing between them. After determining the delay value averaged over the group of output pulses subsequent output pulses are restored to their normal spacing and time locations.

To speed up output clock alignment in a digital phase locked loop wherein a controlled oscillator generates synthesizer pulses that are divided to produce output pulses at a predetermined normal spacing and time location, and wherein during an alignment procedure the output pulses are moved in time in response to a delay value obtained by comparing a phase of the output pulses with a phase applied to the controlled oscillator averaged over a number of synthesizer pulses in a feedback circuit to align said output pulses with a reference clock taking into account hardware delay, a group of the output pulses is advanced during the alignment procedure to reduce the spacing between them. After determining the delay value averaged over the group of output pulses subsequent output pulses are restored to their normal spacing and time locations.

The present disclosure provides an adaptive adjustment circuit in a computer chip having a voltage-controlled oscillator (VCO) and a processor. The adaptive adjustment circuit comprises a frequency difference acquisition module to generate a frequency difference signal based on a first difference between an oscillation frequency of the VCO and a target frequency. The adaptive adjustment circuit also includes a power module to supply a working voltage to the VCO and the processor, adjust the working voltage based on the frequency difference signal, and supply the adjusted working voltage to the VCO and the processor.

A delay locked loop includes a delay line, a delay circuit, a phase detector, a delay code generator, and a delay controller. The delay line may delay an input clock signal in units of unit delay in response to a delay control code to generate an output clock signal. The delay circuit may delay the output clock signal to generate a delay clock signal. The phase detector may compare the input clock signal and the delay clock signal to generate a phase detection signal. The delay code generator may compare the input clock signal and the delay clock signal to detect a phase difference therebetween, and generate a delay code using the phase difference. The delay controller may generate the delay control code using the delay code and the phase detection signal.