Abstract:
Apparatus and associated methods relating to reducing lock time include pre-calibrating and storing phase-locked loop (PLL) and/or injection-locked oscillator (ILO) adaptation values during startup and loading the pre-calibrated values during rate change. In an illustrative example, an integrated circuit may include a controllable frequency circuit operable at frequencies within each of a plurality of frequency bands. A data store may store operational settings associated with each frequency of the plurality of frequency bands. A state machine may be coupled to the controllable frequency circuit and the data store configured to select a predetermined frequency band in response to a command signal, retrieve, from the data store, operational settings associated with the predetermined frequency band, and, apply the retrieved operational settings to the controllable frequency circuit. With the pre-calibration, PLL and/or ILO lock times during rate change in a multi-rate serializer/deserializer (SERDES) link may be advantageously reduced.
Abstract:
A data driver includes pre-driver circuitry coupled to a digital-to-analog converter (DAC) via a plurality of bit lines. The pre-driver circuitry is configured to receive a plurality of first voltages corresponding to respective bits of a digital codeword. Each of the first voltages may have one of a first voltage value or a ground potential based on a value of the corresponding bit. The pre-driver circuitry is further configured to drive a plurality of second voltages onto the plurality of bit lines, respectively, by switchably coupling each of the bit lines to ground or a voltage rail based at least in part on the voltage values of the plurality of first voltages. The voltage rail provides a second voltage value that is greater than the first voltage value. The DAC converts the plurality of second voltages to an electrical signal which is an analog representation of the digital codeword.
Abstract:
A clock and data recovery (CDR) circuit includes a phase detector, a digital loop filter, and a lock detector. The phase detector generates a phase detect result signal in response to phase detection of a plurality of samples. The plurality of samples are generated by sampling a received signal based on a sampling clock a sampling clock provided by a phase interpolator. The digital loop filter includes a phase path and a frequency path for providing a phase path correction signal and a frequency path correction signal based on the phase detect result signal respectively. A phase interpolator code generator generates a phase interpolator code for controlling the phase interpolator based on the phase path correction signal and frequency path correction signal. The lock detector generates a lock condition signal based on the frequency path correction signal, the lock condition signal indicating a lock condition of the CDR circuit.
Abstract:
An example photodiode emulator circuit includes: a first current source circuit; first and second transistors having sources coupled together and coupled to an output of the first current source circuit, a drain of the second transistor coupled to a first node; a third transistor coupled between a drain of the first transistor and a replica load circuit; a second current source circuit coupled to the first node; a capacitor coupled between the first node and electrical ground; and a fourth transistor having a source coupled to the first node and a drain that supplies an output current.
Abstract:
Techniques for correcting clock distortion. The techniques include use of circuitry for detecting and correcting duty cycle distortion and quadrature clock phase distortion. For phase detection, detection circuitry is made simpler and more accurate through the use of a sampling operation in which device mismatch within detection circuitry is accounted for by sampling charge associated with an ideal clock signal across sampling capacitors. When phase detection is performed with the detection circuitry, the stored charge compensates for the device mismatch, improving the accuracy of the detection circuit. The sampling operation is used for duty cycle distortion detection as well. Specifically, a common mode voltage is applied to sampling capacitors, which effectively zeroes the voltage differential between the sampling capacitors, compensating for offset that might exist due to operation of other components of the detection circuit. A digital value is used by a feedback algorithm to correct the clock distortion.
Abstract:
Methods and apparatus are described for synchronously stepping at least one of a data phase interpolator (PI) code or a crossing PI code in a clock and data recovery (CDR) circuit until one or more preset criteria are satisfied. One example method generally includes determining that a condition has been met; based on the determination, stepping, in a CDR circuit, at least one of a data PI code or a crossing PI code for each cycle of a clock; stopping the stepping based on one or more criteria to generate a predetermined state of the data PI code and the crossing PI code, wherein the predetermined state comprises an offset between the data PI code and the crossing PI code; receiving a data stream; and performing clock and data recovery on the data stream based on the offset between the data PI code and the crossing PI code.
Abstract:
An integrated circuit (IC) device includes a controller circuitry having an input coupled to a photodiode of an optoelectronic circuitry and an output coupled to a heater of the optoelectronic circuitry, the controller circuitry configured to determine a center frequency of the optoelectronic circuitry based on a shape of an input signal received from the photodiode, and provide a heater signal to the heater based on the shape of the input signal and the center frequency of the optoelectronic circuitry.
Abstract:
Examples described herein provide for an isolation design for an inductor of a stacked integrated circuit device. An example is a multi-chip device comprising a chip stack comprising: a plurality of chips, neighboring pairs of the plurality of chips being bonded together, each chip comprising a semiconductor substrate, and a front side dielectric layer on a front side of the semiconductor substrate; an inductor disposed in a backside dielectric layer of a first chip of the plurality of chips, the backside dielectric layer being on a backside of the semiconductor substrate of the first chip opposite from the front side of the semiconductor substrate of the first chip; and an isolation wall extending from the backside dielectric layer of the first chip to the front side dielectric layer, the isolation wall comprising a through substrate via of the first chip, the isolation wall being disposed around the inductor.
Abstract:
Apparatus and associated methods relating to reducing lock time include pre-calibrating and storing phase-locked loop (PLL) and/or injection-locked oscillator (ILO) adaptation values during startup and loading the pre-calibrated values during rate change. In an illustrative example, an integrated circuit may include a controllable frequency circuit operable at frequencies within each of a plurality of frequency bands. A data store may store operational settings associated with each frequency of the plurality of frequency bands. A state machine may be coupled to the controllable frequency circuit and the data store configured to select a predetermined frequency band in response to a command signal, retrieve, from the data store, operational settings associated with the predetermined frequency band, and, apply the retrieved operational settings to the controllable frequency circuit. With the pre-calibration, PLL and/or ILO lock times during rate change in a multi-rate serializer/deserializer (SERDES) link may be advantageously reduced.
Abstract:
A frequency divider circuit (200) includes a frequency sub-divider (201) to provide a frequency divided clock, a delay circuit (250) configured to delay the frequency divided clock by N+0.5 cycles of the input clock to generate a delayed clock, and an output circuit (202) configured to generate an output clock based on the frequency divided clock and the delayed clock, where the output clock has a frequency that is equal to 1/(N+0.5) times a frequency of the input clock, and N is an integer greater than one.