Integrated Device Technology, Inc.

Other

Silicon Clocks, Inc.

Jagdeep Singh Bal

Richard Steven Miller

Min Chu

Pankaj Goyal

Eduard Van Keulen

Elie Ayache

Colin Wai Mun Leong

Tao Jing

I-Chang Wu

Stephen E Aycock

Louis F Poitras

Cheng Wen Hsiao

Ron Wade

Arvind Sridhar

A time-to-digital converter obtains a Start signal to indicate the start of an event, and a Stop signal whose assertion indicates the stop of the event. The Stop signal can be asserted multiple times due to false indications of the event stop. The TDC continuously monitors the Stop signal to generate a separate digital value for the duration from the event's starting time to each assertion of the Stop signal. The digital values can be analyzed to select the true duration of the event. Other features and embodiments are also provided.

Apparatus and methods for automatic time measurements

A system includes a first device comprising a first clock generating circuit and a transmitter circuit, and a plurality of second devices, each comprising a respective receiver circuit and a respective second clock generating circuit. The first clock generating circuit may be configured to generate a first clock signal, which may provide internal clocking for the first device. The transmitter circuit may be configured to generate a synchronization signal in response to the first clock signal and wirelessly transmit a broadcast signal communicating only the synchronization signal. The respective receiver circuit may be configured to receive the broadcast signal and present a recovered synchronization signal to the respective second clock generating circuit. The respective second clock generating circuit may be configured to generate a respective intermediate clock signal, synchronize the respective intermediate clock signal with the recovered synchronization signal, and generate a respective second clock signal that provides internal clocking for the second device.

Wirelessly synchronized clock networks

An apparatus includes a plurality of independently clocked devices and a low frequency beacon. Each of the plurality of independently clocked devices has a respective local clock generator. The low frequency beacon communicates a low frequency synchronization signal to each of the independently clocked devices. The respective local clock generators of the plurality of independently clocked devices are generally synchronized using the low frequency synchronization signal.

Separate clock synchronous architecture

An apparatus includes a first independently clocked device and one or more second independently clocked devices. The first independently clocked device may comprise a clock generator. The clock generator may be configured to generate a clock signal. The first independently clocked device may be configured to wirelessly broadcast a synchronization signal based on the clock signal. The one or more second independently clocked devices may each comprise respective clock generators. The one or more second independently clocked devices may (a) be configured to receive the synchronization signal from the first independently clocked device and (b) synchronize the respective clock generators to the clock signal of the first independently clocked device in response to the synchronization signal.

A clock generator having deskewed outputs signals wherein a transit time of each of a plurality of traces coupled to the clock generator outputs are determined and the longest trace is identified as the trace having the longest transit time. A time delay is then added to an output clock signal at each of the clock generator outputs that are not coupled to the longest trace. The addition of the time delay for each of the clock generator outputs is effective in automatically deskewing the clock generator outputs.

System and method for deskewing output clock signals

An integrated circuit comprising, a resonator, a first clock circuit for generating a first clock signal having a first frequency in response to the resonator, a second clock circuit for generating a second clock signal having a second frequency in response to the resonator, wherein the second frequency of the second clock signal is determined by the programmable frequency divider and a clock mode control circuit coupled to the first clock circuit and the second clock circuit, the clock mode control circuit for gradually switching the resonator between the first oscillator circuit and the second oscillator circuit of the integrated circuit, using a shift register based state machine and utilizing the inertia of the resonator to smoothly transition between the two oscillators, to provide a dual mode clock output signal.

Dual mode clock using a common resonator and associated method of use

An integrated circuit to remove jitter from a clock signal includes an integrated circuit die. The integrated circuit die includes a signal comparator. The signal comparator is configured to determine a frequency difference between a jittery input clock signal and a correction signal. A digital low pass filter is coupled to receive and filter the frequency difference and to provide a filtered output signal. A free running crystal-less oscillator produces a reference signal. A fractional output divider is coupled to the free running crystal-less oscillator and the digital low pass filter. The fractional output divider utilizes the filtered output signal to establish a value to divide the reference signal by to obtain a clean output clock signal. The clean output clock signal is fed back to the signal comparator and is used as the correction signal.

Crystal-less jitter attenuator

Methods and apparatuses are described to convert analog signals to digital signals using a local charge averaging capacitor array (LCACA) in an analog-to-digital converter (ADC.) An apparatus includes a comparator. The comparator is configured with a first high input, a first low input, and is configure to receive a clock signal. A logic/latch block is configured to receive the clock signal and an output from the comparator. The logic/latch block is configured to output a control signal and a digital N-bit output signal. A local charge-averaging capacitor array (LCACA) is configured to receive the control signal and a reference voltage. An output of the LCACA is coupled to the first low input. The first LCACA is divided into a high sub-array and a low sub-array. The high sub-array is pre-charged to a high reference voltage and the low sub-array is pre-charged to a low reference voltage. The high reference voltage is greater than the low reference voltage. In operation, an analog signal is input to the first high input and the digital N-bit output signal is the digital conversion of the analog signal.

Methods and systems for analog-to-digital conversion (ADC) using an ultra small capacitor array with full range and sub-range modes

Methods and apparatuses are described to reduce phase noise in a low noise fractional reference-injection phase locked loop (FRIPLL). The FRIPLL includes a ring voltage controlled oscillator (VCO). An output of the ring VCO is input to a fractional interpolative frequency divider (FIFD). A signal comparison circuit receives a reference clock signal and a further delayed output of the FIFD. The signal comparison circuit produces a control voltage signal in response to a phase difference between the reference clock signal and the further delayed output of the FIFD. The control voltage signal is input to the ring VCO to control a ring VCO frequency. An oscillator control circuit has a first input and a second input. The first input is a first delayed output of the FIFD. The second input is the reference clock signal. The oscillator control circuit generates a realignment signal which is used to realign a state transition in a ring VCO output signal to the reference clock signal when the ring VCO output signal is in a low state. Realignment occurs repeatedly at a frequency of the reference clock signal.

Fractional reference-injection PLL

A fractional N-frequency divider having a reduced fractional spurious output signal, which utilizes a multi-modulus frequency divider and an accumulator to generate a calibration-timing window that is used to calibrate two oscillator circuits and a phase compensation circuit. The calibrated phase compensation circuit is then used to mitigate the fractional spurs in the output signal of the fractional N-frequency divider. The fractional N-frequency divider may be implemented into a fractional N-frequency synthesizer.

Low-spurious fractional N-frequency divider and method of use

Integrated circuit devices include first and second periodic signal generators and a power down detection circuit. The first periodic signal generator is configured to generate at least a first periodic signal having a first frequency at an output thereof and the second periodic signal generator is configured to generate a second periodic signal having a second frequency less than the first frequency at an output thereof. The power down detection circuit is configured to selectively provide one or the other of the first and second periodic signals to an output terminal of the integrated circuit device, in response to monitoring a status of a signal received at an input terminal of the integrated circuit device. This received signal reflects a power down status of an external device that receives the selected one of the first and second periodic signals.

Clock distribution systems for low power applications

A clock signal generator includes a phase-lock loop for generating an imaging clock signal having a frequency based on a reference clock signal. The imaging clock signal generator also includes a modulation circuit for determining a number of pixels in a horizontal line of an image to be generated based on the imaging clock signal. The modulation circuit generates a modulation signal based on the determined number of pixels and the clock signal generator spreads the frequency of the imaging clock signal across a frequency range based on the modulation signal. In this way, the clock signal generator reduces electromagnetic interference in the imaging clock signal. In further embodiments, the clock signal generator generates an adjustment signal for adjusting the frequency range based on the frequency of the reference clock signal and the frequency of the imaging clock signal.

Spread spectrum clock generation technique for imaging applications

A clock circuit includes a phase-lock loop for generating an output clock signal based on a data signal and a harmonic frequency detector for detecting whether the frequency of the output clock signal is a harmonic frequency of a frequency of a reference clock signal. The harmonic frequency detector includes a counter for generating a first divided clock signal by dividing the frequency of the output clock signal by a first divisor. Additionally, the harmonic frequency detector includes a counter for generating a second divided clock signal by dividing the frequency of the reference clock signal by a second divisor. The harmonic frequency detector also includes a frequency comparator for generating an output indicating whether the frequency of the output clock signal is a harmonic frequency of the frequency of the reference clock signal based on the first divided clock signal and the second divided clock signal.

Clock circuit with harmonic frequency detector

A hybrid frequency synthesizer includes an analog phase lock loop (PLL), a digital PLL, and a control circuit to control an output oscillator. The control circuit assigns control of the output oscillator between the analog PLL and/or the digital PLL depending on a state of lock of the analog PLL and/or the digital PLL. During a frequency acquisition mode, the digital PLL provides a coarse control of the output oscillator. During a phase capture mode, the analog PLL provides a fine control and the digital PLL provides a coarse control of the output oscillator. During the phase capture mode, the analog PLL control signal and the digital PLL control signal may be given a percentage of control over the output oscillator depending on the state of lock of the analog PLL and/or the digital PLL. During a phase lock mode, the analog PLL controls the output oscillator.

Method and apparatus for a hybrid phase lock loop frequency synthesizer

A hybrid frequency synthesizer includes an analog phase lock loop (PLL), a PLL, and a control circuit to control an output oscillator. The control circuit combines a control signal from the analog PLL with a control signal from the digital PLL to form a composite control signal. The composite control signal is conditioned depending on a state of lock of the analog PLL and/or the digital PLL. The composite signal controls the phase and frequency of the output oscillator. The analog control signal and the digital PLL control signal may be given a percentage of over the hybrid frequency synthesizer depending on the state of lock of the PLL and/or the digital PLL. The composite control signal provides both rapid, accurate, and robust acquisition by the digital PLL, and a smooth transition thereafter to low noise phase lock by the analog PLL.

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Saratoga, CA, United States of America

Jagdeep Singh Bal