A phase-locked loop for a driver circuit for operating a MEMS gyroscope, including a seismic mass that is excitable into oscillations. The phase-locked loop including an input interface for receiving position signals that represent the present position of the oscillating seismic mass of the MEMS gyroscope, a phase detector for ascertaining the phase and frequency of the present oscillation movement of the seismic mass, based on the received position signals, at least two oscillators that are alternatively activatable, the alternatively activatable oscillators having different energy consumptions and/or different noise properties, and at least one output interface for outputting a signal that is provided by the oscillator that is presently activated.

An integrated circuit that includes a generating circuit is described. During operation, the generating circuit may provide an edge clock having a target phase within a clock period of an input clock, where the generating circuit does not include a delay-locked loop (DLL). For example, the generating circuit may include a gated ring oscillator that provides a reference clock having a first fundamental frequency that is larger than a second fundamental frequency of the input clock. Note that the gated ring oscillator may be programmable to adjust the first fundamental frequency within a predefined range of values. Moreover, the generating circuit may include a control circuit that determines a reference count of a number of edges of the reference clock within a reference period of the reference clock.

In an embodiment a method includes generating a low-frequency clock signal having a first frequency, in a standby mode and in a run mode of the CPU, generating a high-frequency clock signal having a second frequency higher than the first frequency, in the run mode, updating a value of the reference time base at each period of the low-frequency clock signal in the standby mode, and accessing the counter register with the high-frequency clock signal in the run mode.

Presented herein are techniques for implementing a differential sub-sampling phase locked loop (PLL). A method includes detecting a common-mode voltage on an output of a differential sub-sampling phase detector operating in the differential sub-sampling phase locked loop, and controlling, based on the common-mode voltage, a duty cycle of a feedback signal of the differential sub-sampling phase locked loop that is fed back to the differential sub-sampling phase detector.

A clock and data recovery circuit includes a sampling circuit, a phase detector, a first processing circuit, a second processing circuit and an oscillator circuit. The sampling circuit is configured to sample input data according to an output clock, and generate a sampling result. The phase detector is configured to generate a detection result according to the sampling result. The first processing circuit is configured to process the sampling result to generate a first digital code. The second processing circuit is configured to accumulate a portion of the first digital code to generate a second digital code. A rate of change of a code value of the second digital code is slower than a rate of change of a code value of the first digital code. The oscillator circuit is configured to generate the output clock according to the detection result, the first digital code and the second digital code.

A clock and data recovery circuit includes a sampling circuit, a phase detector, a first processing circuit, a second processing circuit and an oscillator circuit. The sampling circuit is configured to sample input data according to an output clock, and generate a sampling result. The phase detector is configured to generate a detection result according to the sampling result. The first processing circuit is configured to process the sampling result to generate a first digital code. The second processing circuit is configured to accumulate a portion of the first digital code to generate a second digital code. A rate of change of a code value of the second digital code is slower than a rate of change of a code value of the first digital code. The oscillator circuit is configured to generate the output clock according to the detection result, the first digital code and the second digital code.

A variable capacitance circuit may operate a Metal Oxide Semiconductor (MOS) transistor or other semiconductor device to switch a capacitor in and out. Several circuits may be combined in a parallel network having offset bias voltages, such that the combined network may produce a variable capacitance over a large voltage range. The variable capacitance circuit may be incorporated into a phase locked loop (PLL) circuit where similar devices may be configured to produce a voltage reference as part of the PLL circuitry. Such a circuit may be immune to temperature, process, or voltage variances, since the current pulse magnitude times the low pass filter resistance times the sensitivity of a controlled voltage oscillator can be held constant.

A digital phase-locked loop (DPLL) may include a time-to-digital converter (TDC) to provide a phase error signal, a frequency-divider to perform frequency division on an output signal to generate a frequency-divided output signal, a delta-sigma-modulator (DSM) to provide a test signal that represents a quantization error of the DSM, and a digital-to-time converter (DTC) to at least partially remove the quantization error from the frequency-divided output signal based on the test signal to generate the feedback signal. The DPLL may include a circuit to cause the DTC to provide a percentage of the quantization error such that the percentage of the quantization error is in the phase error signal, and a TDC calibration component to calibrate the TDC by applying a gain adjustment factor to the TDC. The gain adjustment factor may be based on the test signal and the phase error signal including the percentage of the quantization error.

A digital phase-locked loop (DPLL) may include a time-to-digital converter (TDC) to provide a phase error signal, a frequency-divider to perform frequency division on an output signal to generate a frequency-divided output signal, a delta-sigma-modulator (DSM) to provide a test signal that represents a quantization error of the DSM, and a digital-to-time converter (DTC) to at least partially remove the quantization error from the frequency-divided output signal based on the test signal to generate the feedback signal. The DPLL may include a circuit to cause the DTC to provide a percentage of the quantization error such that the percentage of the quantization error is in the phase error signal, and a TDC calibration component to calibrate the TDC by applying a gain adjustment factor to the TDC. The gain adjustment factor may be based on the test signal and the phase error signal including the percentage of the quantization error.

Presented herein are techniques for implementing a differential sub-sampling phase locked loop (PLL). A method includes detecting a common-mode voltage on an output of a differential sub-sampling phase detector operating in the differential sub-sampling phase locked loop, and controlling, based on the common-mode voltage, a duty cycle of a feedback signal of the differential sub-sampling phase locked loop that is fed back to the differential sub-sampling phase detector.