A PLL includes a controlled oscillator, a phase accumulator to measure the controlled oscillator output phase, a phase predictor to calculate the required output phase, and a phase subtractor to calculate the phase difference or phase error. The phase accumulator includes a counter whose output sequence changes only one bit per counted controlled oscillator output cycle, such as a Gray counter. It further includes a register or latches, which sample(s) the counter output value upon receiving a reference clock pulse. The latches output value represents the measured phase. A binary encoder, such as a Gray-to-binary converter, may translate the measured phase to a binary number. The phase accumulator may further include a delay line, second latches, and a delay line decoder to measure a fractional part of the phase. A calibration feedback loop may keep the number of delay line steps per output clock pulse known and stable.

Methods and circuits are provided for range extension of a phase-locked loop (PLL). The PLL uses a phase subtractor with a limited unextended range. It also includes first and second registers and combinatorial logic. The phase subtractor calculates the current phase difference. The first register stores the previous phase difference. The combinatorial logic determines, from the current phase difference and the previous phase difference, if a range excursion occurs, and if it is upward or downward. When an upward excursion occurs, the value in the second register is incremented. When a downward excursion occurs, the value of the second register is decremented. The bits in the second register are combined with the bits of the current phase difference to obtain an extended current phase difference.

A PLL has a controlled oscillator with a limited frequency range. It has a phase accumulator and a phase predictor whose ranges are limited to a value K related to their bit width. K is less than the ratio of the maximum output frequency and the minimum reference frequency. The PLL locks the output frequency to a value higher than the FCW times the reference frequency. The PLL includes a means for setting the output frequency to a target frequency before achieving final lock. The PLL may have a lock detector. After acquiring lock, the PLL may reduce the bit width and K value, for example by cutting power to or switching off some of the bits, or by switching off slow counters in a multi-counter system.

A PLL has a frequency comparator that is active during lock-in. It outputs a signal related to the difference between the oscillator frequency and a target frequency. It captures an initial phase and observes change in phase relative to the initial phase. Two ways of capturing the initial phase are provided. The frequency comparator can provide input signals for the loop filter and make the PLL act as a frequency-locked loop during lock-in. Alternatively, it can provide input signals for a search controller that may perform a binary or other search. The frequency comparator may wait one or more cycles of the reference clock signal to reduce noise, or it may set a threshold to eliminate some noise. It may signal that the oscillator frequency equals the target frequency when the threshold has not been exceeded after a timeout. The search controller may directly or indirectly control the PLL's oscillator.

A PLL has a frequency comparator that is active during lock-in. It outputs a signal related to the difference between the oscillator frequency and a target frequency. It captures an initial phase and observes change in phase relative to the initial phase. Two ways of capturing the initial phase are provided. The frequency comparator can provide input signals for the loop filter and make the PLL act as a frequency-locked loop during lock-in. Alternatively, it can provide input signals for a search controller that may perform a binary or other search. The frequency comparator may wait one or more cycles of the reference clock signal to reduce noise, or it may set a threshold to eliminate some noise. It may signal that the oscillator frequency equals the target frequency when the threshold has not been exceeded after a timeout. The search controller may directly or indirectly control the PLL's oscillator.

The invention relates to a method for determining the phase difference between a first clock signal (CK1) received by a first electronic component (CE1) and a second clock signal (CK2) received by a second electronic component (CE2), comprising the steps of: S10) transmitting a first calibration signal (S12); S20) measuring a first delay (T.sub.1); S30) transmitting a second calibration signal (S21); S40) measuring a second delay (T.sub.2); S50) measuring the number (n) of clock pulses between the transmission of the first calibration signal (S12) and the active edge of the first clock signal (CK1) consecutive to the active edge of the second calibration signal (S21); S60) determining the phase difference depending on the parity of the number (n) of clock pulses.

The invention relates to a method for determining the phase difference between a first clock signal (CK1) received by a first electronic component (CE1) and a second clock signal (CK2) received by a second electronic component (CE2), comprising the steps of: S10) transmitting a first calibration signal (S12); S20) measuring a first delay (T.sub.1); S30) transmitting a second calibration signal (S21); S40) measuring a second delay (T.sub.2); S50) measuring the number (n) of clock pulses between the transmission of the first calibration signal (S12) and the active edge of the first clock signal (CK1) consecutive to the active edge of the second calibration signal (S21); S60) determining the phase difference depending on the parity of the number (n) of clock pulses.

A memory device includes a clock input configured to receive a clock from a host device. The memory device also includes a command input configured to receive command and address bits from the host device. The memory device further includes multiple die stacked in a three-dimensional stack. A first die of the plurality of die includes a first plurality of memory cells and first local control circuitry. The first local circuitry includes division circuitry configured to receive the clock from the clock input, generate a divided clock having a lower frequency than that of the clock, and generate multiple clocks from the divided clock with each of the multiple clocks having a lower frequency than the divided clock. The memory device also includes one or more transmitters configured to transmit the multiple clocks using a inter-die interconnects between the multiple die.

A memory device includes a clock input configured to receive a clock from a host device. The memory device also includes a command input configured to receive command and address bits from the host device. The memory device further includes multiple die stacked in a three-dimensional stack. A first die of the plurality of die includes a first plurality of memory cells and first local control circuitry. The first local circuitry includes division circuitry configured to receive the clock from the clock input, generate a divided clock having a lower frequency than that of the clock, and generate multiple clocks from the divided clock with each of the multiple clocks having a lower frequency than the divided clock. The memory device also includes one or more transmitters configured to transmit the multiple clocks using a inter-die interconnects between the multiple die.

A clock generator comprise a delta-sigma modulation, DSM, for generating a division control signal and a phase control signal, an oscillator, for generating an oscillation signal with a first frequency, an adjustable frequency divider, for performing a division operation on the oscillation signal according to the division control signal, to generate a first division signal and a second division signal with a second frequency, and a phase interpolator, PI, for performing a phase interpolation operation on the first and second division signals according to the phase control signal, to generate an output signal with an output frequency, wherein the first frequency is greater than the second frequency.