Stmicroelectronics International N.v.

Stmicroelectronics Pvt. Ltd.

Stmicroelectronics S.a.

Stmicroelectronics (crolles 2) Sas

Kallol Chatterjee

Chittoor Parthasarathy

Nitin Chawla

Gagan Midha

Nitin Agarwal

Anurag Ramesh Tiwari

Anand Kumar

Paras Garg

Atul Dwivedi

Pascal Urard

Abhishek Jain

Promod Kumar

Nitin Bansal

Nitin Jain

Ankit Gupta

Pierre Dautriche

Pijush Kanti Panja

Gauri Mittal

Pradeep Kumar Badrathwal

Samala Sreekiran

Nitin Kumar Gupta

Vinod Kumar

Saurabh Kumar Singh

Saiyid Mohammad Irshad Rizvi

Rohit Kumar Gupta

SaurabhKumar Singh

Tanmoy Sen

Deependra Kumar Jain

Pallavi Muktesh

Junaid Yousuf

Vijender Singh Chauhan

Anurup Mitra

Jeet Narayan Tiwari

Deependra Jain

A low power crystal oscillator circuit has a high power part and a low power part. Crystal oscillation is initialized using the high power part. An automatic amplitude control circuit includes a current subtractor that decreases current in the high power part as an amplitude of the crystal oscillation increases. A current limiting circuit may limit current in the low power part in order to further reduce power consumption by the low power crystal oscillator circuit. Additionally, an automatic amplitude detection circuit may turn off the high power part after the amplitude of the crystal oscillation reaches a predetermined level in order to further reduce power consumption of the low power crystal oscillator circuit, and may turn back on the high power part after the amplitude of the crystal oscillation reaches a second predetermined level in order to maintain the crystal oscillation.

Low power crystal oscillator with automatic amplitude control

A method for determining temperature of a chip, includes generating a first voltage and a second voltage using a pair of bipolar-junction transistors, and generating a third voltage using another bipolar-junction transistor. When a most recent bit of a bitstream is a logic-zero, the difference between the first and second voltages is sampled using a switched-capacitor input-sampling circuit, and a difference between the first and second voltages is integrated, to produce a proportional-to-absolute-temperature voltage. The proportional-to-absolute-temperature voltage is quantized to produce a next bit of the bitstream. When the most recent bit of the bitstream is a logic-one, the third voltage is sampled using the switched-capacitor input-sampling circuit, and the third voltage is integrated, to produce a complementary-to-absolute-temperature voltage. The complementary-to-absolute-temperature voltage is quantized to produce a next bit of the bitstream. The bitstream is filtered and decimated to produce an output code representative of the temperature of the chip.

Method for implementing Vptat multiplier in high accuracy thermal sensor

Provided is a voltage level shifter that operates in sub-threshold voltages. The level shifter includes a level shifting stage. The level shifting stage receives a first signal from a first voltage domain and outputs a second signal to a second voltage domain. The level shifter includes a first auxiliary stage. In response to the first signal having a first voltage level corresponding to a first logical state and a first node of the level shifting stage having a supply voltage level, the first auxiliary stage sources current to a second node of the level shifting stage. Sourcing the current to the second node accelerates a transition of the first node to a reference voltage. The level shifting stage outputs a second signal to a second voltage domain.

Voltage level shifter for sub-threshold operation

A temperature sensing circuit a switched capacitor circuit selectively samples ΔVbe and Vbe voltages and provides the sampled voltages to inputs of an integrator. A quantization circuit quantizes outputs of the integrator to produce a bitstream. When a most recent bit of the bitstream is a logic zero, operation includes sampling and integration of ΔVbe a first given number of times to produce a voltage proportional to absolute temperature. When the most recent bit of the bitstream is a logic one, operation includes cause sampling and integration of Vbe a second given number of times to produce a voltage complementary to absolute temperature. A low pass filter and decimator filters and decimates the bitstream produced by the quantization circuit to produce a signal indicative of a temperature of a chip into which the temperature sensing circuit is placed.

A phase lock loop (PLL) includes an input comparison circuit configured to compare a reference signal to a divided feedback signal and generate at least one charge pump control signal based thereupon. A charge pump generates a charge pump output signal in response to the at least one charge pump control signal. A loop filter is coupled to receive and filter the charge pump output signal to produce an oscillator control signal. An oscillator generates an output signal in response to the oscillator control signal, with the output signal divided by a divisor using divider circuitry to produce the divided feedback signal. Divisor generation circuitry is configured to change the divisor over time so that a frequency of the divided feedback signal changes from a first frequency to a second frequency over time.

High performance phase locked loop for millimeter wave applications

A PLL includes an input comparison circuit comparing a reference signal to a divided feedback signal to thereby control a charge pump that generates a charge pump output signal. A filter receives the charge pump output signal when a switch is closed, and produces an oscillator control signal causing an oscillator to generate an output signal. Divider circuitry divides the output signal by a divisor to produce the divided feedback signal. Divisor generation circuitry changes the divisor over time so the output signal ramps from a start frequency to an end frequency. Modification circuitry stores a first oscillator control signal equal to the value of the oscillator control signal when the frequency of the output signal is the start ramp frequency. When the frequency of the output signal reaches the end ramp frequency, the switch is opened, and the stored first oscillator control signal is applied to the loop filter.

A delay chain circuit with series coupled delay elements receives a reference clock signal and outputs phase-shifted clock signals. A multiplexer circuit receives the phase-shifted clock signals and selects among the phase-shifted clock signals for output as in response to a selection signal. The selection signal is generated by a control circuit from a periodic signal having a triangular wave profile. A sigma-delta modulator converts the periodic signal to a digital signal, and an integrator circuit integrates the digital signal to output the selection signal. The selected phase-shifted clock signal is applied as the reference signal to a phase locked loop which generates a spread spectrum clock signal.

Delay-based spread spectrum clock generator circuit

Disclosed herein is a fine capacitance tuning circuit for a digitally controlled oscillator. The tuning circuit has low and high frequency tuning banks formed by varactors that have their top plates connected to one another. A controller initially sets states of switches selectively connecting the bottom plates of the varactors of the low frequency bank to a low voltage, a high voltage, or to an RC filter, in response to an integer portion of a control word. A sigma-delta modulator initially sets the states of switches selectively connecting the bottom plates of the varactors of the high frequency bank to either the low voltage or the high voltage, in response to a fractional portion of the control word. The controller modifies the states of the switches of the tuning banks in a complementary fashion, based upon comparisons between the fractional portion of the control word and a series of thresholds.

Digitally controlled LC oscillator

A low-voltage-differential-signaling (LVDS) fault detector includes first and second LVDS lines, and a window comparator provides a first output indicating whether a difference between voltages at the first and second LVDS lines is greater than a threshold voltage, and a second output indicating whether a difference between the voltages at the second and first LVDS lines is greater than the threshold voltage. A charge circuit charges a capacitive node when either the first or second output is at a logic low, and discharges the capacitive node when neither the first nor second output is at a logic low. A Schmitt trigger generates a fault flag if charge on the capacitive node falls to a threshold.

Low voltage differential signaling fault detector

A phase locked loop (PLL) circuit disclosed herein includes a phase detector receiving a reference frequency signal and a feedback frequency signal and configured to output a digital signal indicative of a phase difference between the reference frequency signal and the feedback frequency signal. A digital loop filter filters the digital signal. A digital to analog converter converts the filtered digital signal to a control signal. An oscillator generates a PLL clock signal based on the control signal. A sigma-delta modulator modulates a divider signal as a function of a frequency control word. A divider divides the PLL clock signal based on the divider signal, and generates a noisy feedback frequency signal based thereupon. A noise filtering block removes quantization noise from the noisy feedback frequency signal to thereby generate the feedback frequency signal.

Fraction-N digital PLL capable of canceling quantization noise from sigma-delta modulator

A circuit includes an oscillator circuit to receive a bias current and generate an oscillating signal at an output node. A current differencing circuit subtracts a current at the output node from a reference current to generate a first current. In addition, a current mirroring circuit mirrors the first current to generate the bias current. An inverter stage is coupled to the output node, and includes an input branch configured to receive the oscillating signal and generate first and second control signals based upon the oscillating signal. At least one amplifying branch receives the first and second control signals and amplifies the first and second control signals. An output branch receives the amplified first and second control signals and generates an amplified version of the oscillating signal based upon the amplified first and second control signals.

Compensation circuit and inverter stage for oscillator circuit

An embodiment of a detector includes first and second generators. The first generator is operable to receive a transition of a first signal and to generate in response to the transition a first pulse having a length that is approximately equal to a length of a detection window. And the second generator is operable to receive a second signal and to generate a second pulse having a relationship to the first pulse in response to a transition of the second signal occurring approximately during the detection window.

Transition detector

A method and apparatus are provided. The apparatus includes a plurality of devices forming a positive feedback loop for driving a regulated output voltage towards a reference voltage. Device ratios of at least two of the plurality of devices are set such that the positive feedback loop is stable.

Voltage regulator

A circuit and method for referenceless CDR with improved efficiency and jitter tolerance by using an additional loop for frequency detection. Such an improved circuit includes a frequency detector for identifying whether an initial recovered clock signal is faster or slower than the actual bit rate of the received data stream. The frequency detector provides a jitter tolerance of +/&#x2212;0.5 UI and uses significantly fewer components that other conventional frequency detectors. Having fewer components, significantly less power is also consumed. In an embodiment, the FD uses only four flip-flops, two AND gates, and one delay circuit. Having fewer components also uses less die space in integrated circuits. Having high jitter tolerance and fewer components is an improvement over conventional referenceless CDR circuits.

Referenceless clock and data recovery circuit

Disclosed is a system and method for providing a critical path replica system in a circuit. A critical path replica system is created by determining a critical path in a circuit, generating a critical path replica circuit, generating a circuit blueprint, and creating the blueprinted circuit. The circuit comprises a functional logic module having functional logic elements and replica logic modules having logic elements. Each logic element is configured to replicate one or more of the functional logic elements and process a test signal. A replica error detection module analyzes the processed signal to determine whether a timing violation has occurred. In some embodiments, the replica logic module further comprises one or more load modules. A replica controller may modify operation of the circuit based on reported errors. A replica mode select module sets the replica logic module to an aging test mode or a timing sensor mode.

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Kolkata, India

Kallol Chatterjee