A master-slave delay locked loop system comprises a master delay locked loop (“MDLL”) and at least one slave delay locked loop (“SDLL”). The MDLL generates one or more biases. Each of the at least one SDLL has a slave calibration unit and slave delay elements. The slave calibration unit calibrates the slave delay elements using a slave calibration loop and the generated one or more bias. Thus, each of the SDLL is calibrated to account for any electrical noise, pressure, voltage, and temperature variations that the respective SDLL experiences.

A master-slave delay locked loop system comprises a master delay locked loop (“MDLL”) and at least one slave delay locked loop (“SDLL”). The MDLL generates one or more biases. Each of the at least one SDLL has a slave calibration unit and slave delay elements. The slave calibration unit calibrates the slave delay elements using a slave calibration loop and the generated one or more bias. Thus, each of the SDLL is calibrated to account for any electrical noise, pressure, voltage, and temperature variations that the respective SDLL experiences.

A phase locked loop is disclosed comprising: a phase detector, a loop filter, a frequency controller oscillator and a lock detector. The phase detector is operable in a bang-bang mode to provide a binary phase error signal indicating whether there is a positive or negative phase difference between a reference signal and a feedback signal. The loop filter is configured to provide a control signal derived from the binary phase error signal. The frequency controlled oscillator is configured to receive the control signal and provide an output signal with a frequency that varies according to the control signal. The lock/unlock detector is configured to determine a lock/unlock state of the phase locked loop, the lock/unlock state derived from a duty cycle and/or spectral content of the binary phase error signal.

A phase locked loop is disclosed comprising: a phase detector, a loop filter, a frequency controller oscillator and a lock detector. The phase detector is operable in a bang-bang mode to provide a binary phase error signal indicating whether there is a positive or negative phase difference between a reference signal and a feedback signal. The loop filter is configured to provide a control signal derived from the binary phase error signal. The frequency controlled oscillator is configured to receive the control signal and provide an output signal with a frequency that varies according to the control signal. The lock/unlock detector is configured to determine a lock/unlock state of the phase locked loop, the lock/unlock state derived from a duty cycle and/or spectral content of the binary phase error signal.

An integrated circuit with a phase-locked loop (PLL) is provided. The PLL may include a phase frequency detector, a charge pump, a source follower circuit, a variable oscillator, a frequency divider, and a control block. The phase frequency detector may be configured to align or lock a feedback clock signal to a reference clock signal. The control block includes clock loss detection circuits that are used to determine whether the reference clock signal or the feedback clock signal has stopped toggling. In response to detecting a clock loss event for either the reference or the feedback clock signal, the control block may disable the phase frequency detector to place the charge pump in a tristate mode and may apply a predetermined bias voltage to the source follower circuit to help minimize electrical overstress.

An integrated circuit with a phase-locked loop (PLL) is provided. The PLL may include a phase frequency detector, a charge pump, a source follower circuit, a variable oscillator, a frequency divider, and a control block. The phase frequency detector may be configured to align or lock a feedback clock signal to a reference clock signal. The control block includes clock loss detection circuits that are used to determine whether the reference clock signal or the feedback clock signal has stopped toggling. In response to detecting a clock loss event for either the reference or the feedback clock signal, the control block may disable the phase frequency detector to place the charge pump in a tristate mode and may apply a predetermined bias voltage to the source follower circuit to help minimize electrical overstress.

A multiplying delay-locked loop circuit includes a delay chain including a plurality of variable delay circuits connected in series and having a delay chain output, and a feedback loop including circuitry for deriving a digital control signal representing magnitude and sign of phase offset in the delay chain output, for controlling delay in ones of the variable delay circuits. The circuitry for deriving a digital control signal includes a sampling time-to-digital converter (STDC) configured to operate on a time delay between inputs to generate the digital control signal. The STDC subtracts a second difference the signals derived from the delay chain output and output of the feedback divider from a first difference between the signals derived from the delay chain output and output of the feedback divider to provide a difference value, and the difference value indicates sign and magnitude of output offset in the delay chain output.

A multiplying delay-locked loop circuit includes a delay chain including a plurality of variable delay circuits connected in series and having a delay chain output, and a feedback loop including circuitry for deriving a digital control signal representing magnitude and sign of phase offset in the delay chain output, for controlling delay in ones of the variable delay circuits. The circuitry for deriving a digital control signal includes a sampling time-to-digital converter (STDC) configured to operate on a time delay between inputs to generate the digital control signal. The STDC subtracts a second difference the signals derived from the delay chain output and output of the feedback divider from a first difference between the signals derived from the delay chain output and output of the feedback divider to provide a difference value, and the difference value indicates sign and magnitude of output offset in the delay chain output.

The disclosure provides a delay estimation device and a delay estimation method. The delay estimation device includes a pulse generator, a digitally controlled delay line (DCDL), a time-to-digital converter (TDC), and a control circuit. The pulse generator receives a reference clock signal, outputs a first clock signal in response to a first rising edge of the reference clock signal, and outputs a second clock signal in response to a second rising edge of the reference clock signal. The DCDL receives the first clock signal from the pulse generator and converts the first clock signal into phase signals based on a combination of delay line codes. The TDC samples the phase signals to generate a timing code based on the second clock signal. The control circuit estimates a specific delay between the first clock signal and the second clock signal based on the timing code.

According to one embodiment, an interface system includes a receiver, a first clock generator, a second clock generator, and a sampling circuit. The receiver is configured to receive a first clock and serial data from a host. The first clock generator includes a first voltage controlled oscillator (VCO) and is configured to generate a second clock on the basis of the first clock. The second clock generator includes a second voltage controlled oscillator (VCO) and is configured to generate a third clock on the basis of the serial data. The sampling circuit is configured to sample reception data on the basis of the third clock and the serial data.