Qualcomm Incorporated

Megachips Corporation

Wenjing Yin

Jeffrey Mark Hinrichs

Xuhao Huang

Debesh Bhatta

Sungmin Ock

Andrew Weil

Xu Zhang

John Abcarius

Anand Gopalan

Robert Martin Ondris

Qingjin Du

A programmable delay-line circuit is provided that includes a single ring oscillator that is calibrated continuously by a calibration logic circuit. A clock edge sampler samples an input clock responsive to a plurality of oscillator output signals from the ring oscillator to form a corresponding plurality of data output signals. A clock edge voter processes the data output signals to identify a first one of the oscillator output signals that samples an edge transition of the input clock. Based upon a desired delay, a decoder selects for a second one of the oscillator output signals to produce an output clock signal.

Programmable delay-line circuit with single delay array and real-time calibration

Certain aspects of the present disclosure provide a relatively compact frequency-locked loop (FLL) using a discrete-time integrator. For certain aspects, the FLL also includes a supplemental oscillator and other circuitry that allows for saving the FLL frequency when a reference clock will be disconnected, maintaining a similar frequency during disconnection, and restoring the FLL frequency when the reference clock is reconnected. One example FLL circuit generally includes: an encoder; a combiner comprising a first input coupled to an output of the encoder; a digital-to-analog converter (DAC) comprising an input coupled to an output of the combiner; a discrete-time integrator comprising an input coupled to an output of the DAC; a voltage-controlled oscillator (VCO) comprising a control input coupled to an output of the discrete-time integrator; and a counter comprising an input coupled to an output of the VCO and comprising an output coupled to a second input of the combiner.

Compact frequency-locked loop architecture for digital clocking

A low-voltage differential signaling receiver is provided that amplifies a differential input voltage to produce a differential output voltage. A signal distortion circuit that detects a distortion in a differential output voltage to assert a signal detection signal that adjusts a gate voltage of a pair of load transistors to reduce the distortion. The load transistors are selectively diode connected to reduce power consumption.

Low-power low-voltage differential signaling receiver with signal distortion correction

A bias current circuit is provided with a bias circuit that generates a bias voltage to control the resistance of an active resistor transistor. The bias circuit is configured to generate the bias voltage to be greater than one-half of a power supply voltage for the current bias circuit and to have a negative temperature dependency to reduce the temperature sensitivity of the bias current circuit.

Low-power temperature-insensitive current bias circuit

A switched capacitor circuit includes a first capacitor coupled in series with a second capacitor in a first mode of operation across differential output terminals of a circuit. The first capacitor and the second capacitor are coupled in an anti-parallel layout in a second mode of operation. The switched capacitor circuit also includes a third capacitor coupled on a first side to a common node of the first capacitor and the second capacitor. The third capacitor is further coupled on a second side to a current source control voltage in the first mode of operation, and coupled between a bias reference voltage and a common mode reference voltage in the second mode of operation.

High impedance passive switched capacitor common mode feedback network

A hybrid pulse-width control circuit is provided that includes a ramp voltage generator for generating a ramp voltage signal. A clock pulse generator asserts an output clock signal responsive to the ramp voltage signal equaling a reference voltage.

Hybrid pulse-width control circuit with process and offset calibration

A switched-capacitor voltage divider is provided that functions to divide an input voltage only while a low-duty-cycle clock pulse signal is asserted. All the switches in the switched-capacitor voltage divider are idle during an off time for the low-duty-cycle clock pulse signal.

Low-power low-duty-cycle switched-capacitor voltage divider

Certain aspects of the present disclosure provide methods and apparatus for implementing a fully differential charge pump circuit that eliminates a source of noise and power consumption by using a low-noise switched-capacitor common-mode feedback (CMFB) circuit, rather than a continuous-time amplifier-based CMFB circuit. The fully differential charge pump circuit presented in this disclosure includes the switched-capacitor CMFB (SC-CMFB) unit connected to differential output nodes of the charge pump and provides a feedback signal to the charge pump to control a common-mode voltage of the differential signals based on a reference common-mode voltage. In certain aspects, a replica phase-frequency detector (PFD), a frequency divider, and a non-overlapping clock generator provides control signals for the SC-CMFB circuit.

Fully differential charge pump with switched-capacitor common-mode feedback

Certain aspects of the present disclosure provide a high-speed AC-coupled inverter-based buffer, which may be used as a buffer for a voltage-controlled oscillator (VCO), for example. One example buffer for a VCO generally includes a first inverter stage having an input node configured to receive a first complementary signal of a differential pair, a second inverter stage having an input node configured to receive a second complementary signal of the differential pair, a biasing stage replicating the first inverter stage or the second inverter stage, wherein an output node of the biasing stage is connected with an input node of the biasing stage, a first impedance coupled between the input node of the first inverter stage and the input node of the biasing stage, and a second impedance coupled between the input node of the second inverter stage and the input node of the biasing stage.

High-speed AC-coupled inverter-based buffer with replica biasing

A PLL circuit includes an oscillator, a detection block, an integral path and a proportional path. The oscillator generates an oscillation signal. The detection block detects a phase difference between the oscillation signal and a reference signal and generates an integral signal that represents an integral value of the phase difference and a proportional signal that represents a current value of the phase difference. The integral path includes a regulator that receives the integral signal and supplies a regulated integral signal to the oscillator, and the regulator has a feedback loop including an error amplifier. The proportional path supplies the proportional signal, separately from the integral signal, to the oscillator. The oscillator generates the oscillation signal having an oscillation frequency controlled by both of the regulated integral signal and the proportional signal such that the phase of the oscillation signal is locked to the phase of the reference signal.

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San Diego, CA, United States of America

Wenjing Yin