Low-power and all-digital phase interpolator-based clock and data recovery architecture
The proposed invention is about an improved method for serial-in and serial-out transceiver applications. The proposed system includes a dual loop phase locked loop (PLL) architecture having a PLL and a phase rotator (PR)-based delay locked loop (DLL). An advantage of this architecture is that a single PLL offers decoupled bandwidths; a wide jitter-tolerance (JTOL) bandwidth for receiving data and a narrow jitter transfer (JTRAN) bandwidth for the data transmission. Thus, the amount of jitter at the output can be substantially reduced relative to the input while offering sufficient jitter tracking bandwidth. Also, this architecture is suitable for low-power applications since a phase shifter in the data path, which is one of the most power-hungry blocks in conventional DPLL designs, is not required.
1. A transceiver comprising:
a phase rotator (PR)-based delay-locked loop and phase-locked loop (D/PLL) unit configured to generate demultiplexed data samples for input data using multiphase clock signals for sampling the input data and a reference clock signal; and
a multiplexer configured to serialize the demultiplexed data samples,
wherein the multiphase clock signals are generated using a first clock signal, for retiming the sampled input data, controlled by the phase-locked loop (PLL) and a second clock signal controlled by the delay-locked loop (DLL),
wherein, for the DLL, the PR-based D/PLL unit comprising:
a plurality of input samplers configured to generate the demultiplexed data samples by time-interleaving using the input data and the multiphase clock signals;
a control code generating unit configured to generate a control code for controlling a phase of the second clock signal;
a first phase rotator configured to add a phase of the first clock signal to a phase of the second clock signal of which a phase is determined using the control code or subtract the phase of the first clock signal from the phase of the second clock signal; and
a plurality of phase interpolators (PIs) configured to generate the multiphase clock signals using an output of the first phase rotator.
2. The transceiver of claim 1 , wherein, for the PLL, the PR-based D/PLL unit further comprises:
a digital accumulator (ACC) configured to limit a phase difference between the first clock signal and the second clock signal; and
a second phase rotator configured to generate the first clock signal of which a phase is shifted using a clock signal outputted from the ACC and the reference clock signal from a frequency-locked loop (FLL).
3. A phase rotator (PR)-based delay-locked loop and phase-locked loop (D/PLL) apparatus comprising:
a plurality of input samplers configured to generate demultiplexed data samples by time-interleaving using a input data and multiphase clock signals generated for sampling the input data based on a first clock signal and a second clock signal;
a control code generating unit configured to generate a control code for controlling a phase of the second clock signal;
a first phase rotator configured to add a phase of the first clock signal to a phase of the second clock signal of which a phase is determined using the control code or subtract the phase of the first clock signal from the phase of the second clock signal;
a plurality of phase interpolators (PIs) configured to generate the multiphase clock signals using an output of the first phase rotator;
a digital accumulator (ACC) configured to limit a phase difference between the first clock signal and the second clock signal; and
a second phase rotator configured to generate the first clock signal of which a phase is shifted using a clock signal outputted from the ACC and the reference clock signal from a frequency-locked loop (FLL).