Abstract: There is provided an oscillation circuit including: a band-gap circuit that outputs an output voltage adjusted for temperature dependency so as to give a constant output voltage independent of temperature; a voltage-current conversion circuit including a first variable resistor, the voltage-current conversion circuit converting an output voltage output from the band-gap circuit into an output current corresponding to the resistance of the first variable resistor and outputting a bias current based on the converted output current; and a CR oscillation circuit including a second variable resistor, a capacitor and a comparator section, the CR oscillation circuit oscillating with an oscillation frequency based on the resistance of the second variable resistor and the capacitance value of the capacitor, and the CR oscillation circuit operating according to the amperage of the bias current the comparator section has input from the voltage-current conversion circuit.

Abstract: A method for compensating an oscillation frequency, a device, and a phase locked loop (PLL) is applied in the LC oscillating loop, including: sending voltage control signals to one end of a variable capacitor of an LC oscillating loop to generate oscillating signals in the LC oscillating loop through the voltage control signals; obtaining variable bias voltage that reflects changes of external parameters; and sending the variable bias voltage to the other end of the variable capacitor to compensate changes to the oscillation frequency of oscillation signals generated in the LC oscillating loop. This disclosure compensates the changes to the oscillation frequency of the circuit that contains the LC oscillating loop and improves the stability of the circuit oscillation frequency by sending bias voltage to one end of the variable capacitor of the LC oscillating loop.

Abstract: A temperature compensation method for a piezoelectric oscillator including a piezoelectric vibrator having a frequency temperature characteristic with a hysteresis characteristic, and an oscillation circuit which oscillates the piezoelectric vibrator and outputs an oscillation signal, wherein, to a temperature compensation circuit which can calculate a quantity of temperature compensation using frequency temperature information indicating a temperature characteristic of an oscillation frequency of the piezoelectric vibrator and temperature information of the piezoelectric vibrator at the time of oscillation of the oscillation signal, the oscillation signal and the frequency temperature information are outputted, includes: calculating, as the frequency temperature information, an intermediate value between elevated-temperature frequency temperature information of the piezoelectric vibrator that is generated in the case where ambient temperature of the piezoelectric vibrator is elevated, and lowered-temperature

Abstract: A servo system is provided for controlling movement of a flexible structure having multiple masses and elements. Each element couples a respective two of the masses and functions as a spring when the flexible structure is subject to a linear or rotational input at or above a frequency at which the respective element exhibits flexure. The servo system includes multiple sensors, where each sensor is disposed relative to a respective one of the masses to sense a respective acceleration. A motor having a torque input may operatively be configured to output one of a linear or rotational force on the first mass based on a torque signal present on the torque input. A servo controller that receives each sensed acceleration from each sensor may generate a compensation feedback signal based on a sum of sensed accelerations. The torque signal may be output to the motor based on the compensation feedback signal.

Abstract: A temperature-compensated oscillator includes a temperature sensor, a temperature compensation circuit, a voltage-controlled oscillation circuit adapted to output an oscillation signal on which temperature compensation is performed based on the temperature compensation voltage, an output circuit adapted to output an ON/OFF signal based on a relationship between variation of the detected-temperature voltage output by the temperature sensor and a reference voltage, a switch circuit adapted to supply the temperature compensation circuit with electrical power in response to the ON/OFF signal, and a sample-and-hold circuit adapted to be switched between a state of outputting the temperature compensation voltage to the voltage-controlled oscillation circuit while holding the temperature compensation voltage output by the temperature compensation circuit, and a state of outputting the temperature compensation voltage held to the voltage-controlled oscillation circuit while cutting the connection to the temperature c

Abstract: A temperature-compensated oscillator includes a temperature compensation circuit adapted to output a temperature compensation voltage, a voltage-controlled oscillation circuit on which temperature compensation is performed based on the temperature compensation voltage, a switch circuit adapted to perform ON/OFF control on power supply to the temperature compensation circuit, and a sample-and-hold circuit adapted to perform switching control between an ON state of outputting the temperature compensation voltage to the voltage-controlled oscillation circuit while being connected to the temperature compensation circuit and holding the temperature compensation voltage output from the temperature compensation circuit when the power is supplied to the temperature compensation circuit, and an OFF state of outputting the temperature compensation voltage held to the voltage-controlled oscillation circuit while cutting connection to the temperature compensation circuit when the power supply to the temperature compensat

Abstract: A mixed signal circuit architecture is disclosed for automatic frequency control and digital temperature compensation in an LC-PLL system. Some embodiments allow for high-volume manufacturing of products such as microprocessors and chipsets, and other circuits that employ LC-PLL technology. In some embodiments, various capacitor loadings can be selected to compensate for variation associated with process, voltage, temperature, and reference frequency. In addition, a multi-leg capacitor bank can be selectively used to further compensate for temperature variation post-lock, in accordance with some embodiments. A programmable timer can be used in some embodiments to allow for loop settling prior to assessing parameters of interest.

Abstract: A semiconductor device contrived to prevent a reference voltage and a reference current which are supplied to a high speed OCO from varying with a change in ambient temperature and/or a change in an external power supply voltage and to reduce the circuit area of a power supply module. The high speed OCO outputs a high speed clock whose magnitude is determined by the reference current and the reference voltage. A logic unit adjusts the values of the reference current and reference voltage, according to the reference voltage and reference current trimming codes related to detected ambient temperature and operating voltage.

Abstract: A device for compensating for the frequency of a resonator includes (a) a temperature sensor, (b) a sequencer determining a second compensation signal on the basis of the temperature and corresponding to a positive value N, and a third compensation signal on the basis of the temperature corresponding to a ratio between a positive integer S and N, S being lower than or equal to N, and (c) a variable counter receiving the compensation signals and generating a fourth output signal every N periods of a clock signal from the resonator and generating a fifth signal for modifying the charge capacity of the resonator.

Abstract: Some embodiments disclosed herein relate to techniques for providing a relatively constant oscillation frequency. In some instances, these techniques can make use of a ring oscillator that is powered by an adaptive voltage supply. The adaptive voltage supply provides a temperature-dependent supply voltage to respective delay elements in the ring oscillator, such that the oscillation frequency of the ring oscillator is approximately constant over a predetermined temperature range. For example, if temperature increases, the supply voltage can be increased proportionally, thereby tending to limit variation in the oscillation frequency delivered by the ring oscillator.

Abstract: A resonator of a VCO includes a fine tuning main varactor circuit, an auxiliary varactor circuit, and a coarse tuning capacitor bank circuit coupled in parallel with an inductance. The main varactor circuit includes a plurality of circuit portions that can be separately disabled. Within each circuit portion is a multiplexing circuit that supplies a selectable one of either a fine tuning control signal (FTAVCS) or a temperature compensation control signal (TCAVCS) onto a varactor control node within the circuit portion. If the circuit portion is enabled then the FTAVCS is supplied onto the control node so that the circuit portion is used for fine tuning. If the circuit portion is disabled then the TCAVCS is supplied onto the control node so that the circuit portion is used to combat VCO frequency drift as a function of temperature. How the voltage of the TCAVCS varies with temperature is digitally programmable.

Abstract: The present invention discloses a continuous voltage controlled oscillator (VCO) frequency temperature compensation apparatus for a phase locked loop (PLL) and a continuous VCO frequency temperature compensation method for a PLL. The system utilizes a VCO with one digital coarse tuning input, a first analog fine tuning input, and a second analog fine tuning input. The system uses the second analog fine tuning inputs to compensate the VCO for frequency shifts due to temperature fluctuation. When the PLL transitions to the fine lock (FL) mode, the system starts driving the second fine tuning input with a differential amplifier. The differential amplifier compares the first fine tuning input with a reference voltage, and drives the second fine tuning input to compensate the first fine tuning input.

Abstract: A thermally-compensated oscillator has a current reference with an output current which relates to an ambient temperature with a first relationship, a ring oscillator having an operating frequency which relates to the ambient temperature with a second relationship, and which receives the output current of the current reference and outputs an oscillator signal, and a level shifter which receives the oscillator signal from the ring oscillator and outputs a corresponding voltage-regulated clock signal.

Abstract: A disclosed current source circuit includes a current mirror circuit having two enhancement-type MOS transistors, a depletion-type MOS transistor configured to be connected to a drain of one of the two enhancement-type MOS transistors and to function as a constant current source, and a resistor configured to have a negative temperature property and be connected to a source of the one of the two enhancement-type MOS transistors.

Abstract: An oscillator may include a crystal resonator, an active element coupled in parallel with the crystal resonator and configured to produce at its output a waveform with an approximate 180-degree phase shift from its input, a voltage regulator a voltage regulator coupled to the active element, a sum of thresholds circuit coupled to the input of the voltage regulator, and a temperature-dependent current source coupled to the input of the voltage regulator. The voltage regulator may be configured to supply a supply voltage to the active element, the supply voltage a function of a reference voltage received at an input of the voltage regulator. The sum of thresholds circuit may be configured to generate the reference voltage such that the reference voltage is process-dependent. The temperature-dependent current source may be configured to generate a temperature-dependent current such that the reference voltage is temperature-dependent.

Abstract: An oscillator arrangement is specified, in which a relaxation oscillator is refined to the extent that the comparator (2) to be used for comparing the voltage across a charge storage device (1) with a switching threshold (VTH) is a current comparator with two current branches (5, 6). One of these two current branches is used in the present case for guiding a charging or discharging current of the charge storage device (1). In this way, a current branch is eliminated, so that the proposed principle is preferably suitable for so-called ultra low power applications.

Abstract: There is provided a temperature compensated piezoelectric oscillator which excels in frequency stability and has a good electronic noise characteristic, and with which a circuit can be structured simply. An auxiliary oscillator unit 21 sharing a crystal substrate 2 with a main oscillator unit 11 outputting a set frequency f0 to an outside is used as a temperature detecting unit 32 detecting a temperature T for obtaining a compensation voltage ?V in a temperature compensated piezoelectric oscillator (TCXO), and electrodes 13, 23 of the main oscillator unit 11 and the auxiliary oscillator unit 21 are provided separately on the crystal substrate 2. For example, a fundamental wave and an overtone are used or a thickness shear vibration and a contour shear vibration are used in the main oscillator unit 11 and the auxiliary oscillator unit 21, respectively.

Abstract: Crystal oscillator control and calibration is disclosed. Temperature and frequency control circuits included on a printed circuit board (PCB) comprising a crystal oscillator are used to determine, for each of a plurality of set points in a range of sensed internal temperatures sensed by an internal temperature sensing circuit or device located adjacent to the oscillator in a thermally insulated region of the PCB, a corresponding compensation required to be applied to maintain a desired oscillator output frequency. The PCB is configured to use at least the determined compensation values and a sensed internal temperature to determine during operation of the PCB a compensation, if any, to be applied to maintain the desired oscillator output frequency.

Abstract: In a crystal-oscillator circuit having a quartz crystal unit, further stabilization of output frequency change at a time of startup of the power supply is achieved. A crystal-oscillator circuit having a quartz crystal unit includes a first variable-capacitance element, which forms an oscillation loop with the quartz crystal unit, and a temperature compensation circuit which provides a first control signal for the first variable-capacitance element to compensate for a temperature characteristic of the quartz crystal unit. In addition, the crystal-oscillator circuit includes a second variable-capacitance element group, and a time constant circuit which provides a time constant signal, which changes with a predetermined time constant, for the second variable-capacitance element group as a second control signal.

Abstract: A frequency synthesizer comprises a VCO group; a phase comparator; and a loop filter. Each VCO includes a varactor and a capacitor bank including a plurality of weighted capacitance elements, and a plurality of switches turned ON and OFF based on a control signal. Also provided a temperature compensation including a varactor correction potential generation circuit, a correction potential generation circuit for parasitic capacitance of the capacitor bank, a variable gain amplifier in which weighting processing, based on a control signal of the capacitor bank, is performed on an output potential of the correction potential generation circuit, and an adder circuit that adds the output voltage of the correction potential generation circuit of the varactor and output voltage of the variable gain amplifier, and the varactor of the VCO is controlled by output (correction potential) of the adder circuit.

Abstract: A constant-temperature type crystal oscillator includes: a surface-mount crystal unit, in which a crystal element is housed in a case main body to hermetically encapsulate the crystal element with a metal cover, and which includes a crystal terminal serving as a mounting terminal that is electrically connected to at least the crystal element on an outer bottom face of the case main body; a thermistor that detects an operational temperature of the surface-mount crystal unit; and a circuit substrate, on which elements forming an oscillator circuit and elements forming a temperature control circuit along with the thermistor are installed. The thermistor includes a first and second terminal electrode and a temperature detecting electrode that is electrically independent of the first and second terminal electrode. The temperature detecting electrode is electrically connected to the crystal terminal of the surface-mount crystal unit through a circuit pattern formed on the circuit substrate.

Abstract: A voltage controlled oscillator having a temperature and process controlled output. A VCO in accordance with the present invention comprises a reference current source, a fixed current source, coupled in series with the reference current source, the fixed current source comprising a temperature independent current source, a third current source, coupled in parallel with the combination of the reference current source and the fixed current source, and an oscillator, coupled in series with the third current source, wherein a current used to control the oscillator is based on operating temperatures and processes of the reference current source and the third current source.

Abstract: A circuit may comprise an amplifier powered by a first supply voltage, with a first input of the amplifier coupled to a stable reference voltage, and the output voltage of the amplifier provided as a designated supply voltage to an oscillator configured to produce a periodic signal having a specified frequency. The circuit may further include a control circuit coupled to a second input of the amplifier, to the output of the amplifier, and to ground, and configured to control the rate of change of the output voltage of the amplifier with respect to temperature. This rate of change may be specified according to a characterization of the oscillator over supply voltage and temperature, and may result in stabilizing the specified frequency across temperature. The periodic signal may therefore be unaffected by variations in the first supply voltage, and the amplitude of the periodic signal may be proportional to the stable reference voltage.

Abstract: Aspects of a method and system for a temperature sensing crystal Integrated circuit with digital temperature output are provided. In this regard, an indication of temperature may be generated in an integrated circuit (IC) comprising a memory, a crystal or crystal oscillator, and at least a portion of an analog-to-digital converter. The temperature indication may be digitized via the analog-to-digital converter. Operation of one or more circuits may be controlled based on the digital temperature indication. The digital temperature indication may be communicated over a communication bus. An analog portion of the analog-to-digital converter may be integrated in the IC and may comprise, for example, a delta-sigma modulator. A digital portion of the analog-to-digital converter may be external to the IC and may comprise, for example, a digital filter.

Abstract: An oscillator circuit comprises a charging block with a first terminal for feeding a first charging current, to which terminal a first capacitor and a series circuit of a first and a second switch are connected, and with a second terminal for feeding a second charging current, to which terminal a second capacitor and a series circuit of a third and a fourth switch are connected, as well as a comparison circuit with a first and a second comparator. The comparators are configured to compare voltages at the first and second terminals to a reference voltage, wherein their output is connected to control terminals of the third or first switch. The oscillator circuit further comprises a flipflop that is coupled on the input side to the outputs of the first and second comparators, and on the output side, to control terminals of the second and fourth switches, as well as to an oscillator output.

Abstract: A thermostatic-chamber temperature control device includes: a heating element for heating a thermostatic chamber; a bridge circuit having a temperature sensitive element whose resistance value varies in accordance with the temperature of the heating element; a detection circuit for detecting an unbalanced voltage of the bridge circuit; a PWM signal generating circuit for generating a PWM signal corresponding to the unbalanced voltage detected by the detection circuit; and a switching element that has a current output terminal connected to the heating element and a current input terminal connected to a power supply circuit and is driven on the basis of the PWM signal generated by the PWM signal generating circuit.

Abstract: The application relates to a calibration apparatus and calibration method for a tuneable resonator of a delta-sigma modulator of the continuous time, band pass type. The calibration apparatus comprises: a resonator driver capable of causing an oscillating behavior in a resonator output signal, a reference signal source that provides a reference signal, a frequency detector that provides a frequency relation signal corresponding to the frequency relation between the resonator output signal and the reference signal, and a controller that controls the tuneable resonator in dependence from the frequency relation signal so as to reduce frequency deviation.

Abstract: A resonator having an effective spring constant (kz) and comprising a beam having a beam spring constant (kB) adapted to resonate in an oscillation direction, and extending at a non-zero angle (?) to the oscillation direction, wherein the resonator has a predetermined geometry and is formed from one or more materials, the or each material having a coefficient of thermal expansion (CTE), the CTE of the or each material together with the predetermined geometry of the resonator causing ? to vary with temperature, such that the temperature dependence of the beam spring constant is compensated for, resulting in the effective spring constant of the resonator remaining substantially constant within an operating temperature range.

Abstract: A temperature compensated crystal oscillator includes an oscillation circuit including a crystal oscillator; a variable capacitor inserted in series in the oscillation circuit; a thermosensitive circuit element whose resistance value changes in accordance with a temperature of the crystal oscillator, the thermosensitive circuit element being formed on the crystal oscillator by vapor deposition; and a correction circuit configured to correct capacitance of the variable capacitor based on a current value that is used when applying current to the thermosensitive circuit element.

Abstract: Aspects of a method and system for an energy efficient temperature sensing crystal integrated circuit (TSCIC) are provided. In this regard, one or more circuits in a temperature sensing crystal integrated circuit (TSCIC) may be configured to control power consumption of the TSCIC. The one or more circuits in the TSCIC may comprise a memory and a crystal. The one or more circuits in the TSCIC may be operable to generate an indication of temperature of the crystal. The one or more circuits in the TSCIC may be configured to control a current supplied to the crystal within the TSCIC, wherein the configuring is based on phase noise requirements of a signal generated by the crystal. Generation of the temperature indication may be enabled or disabled. The enabling or disabling may occur based on a rate of change of a temperature in the TSCIC.

Abstract: An integrated circuit (IC) with a low temperature coefficient and an associated calibration method are provided to lower the effect of the environmental temperature on the IC and at the same time to maintain the small area and low power consumption of the IC. The IC includes a first circuit, a second circuit and a calibration control circuit. The first circuit has a low temperature coefficient and generates a first output. The second circuit has a high temperature coefficient and generates a second output. The calibration control circuit detects the first and second outputs, and compares the first and second outputs according to a predefined relationship therebetween so as to generate an adjusting signal. The adjusting signal is for adjusting the second circuit such that the second circuit can have the characteristic of the low temperature coefficient.

Abstract: A temperature controlled oscillator is provided with a circuit substrate having a crystal resonator, an oscillating circuit, and a temperature control circuit, arranged on one or both principal surfaces, and a container main body that accommodates the circuit substrate and has mount terminals on an outer bottom surface thereof. The temperature control circuit includes at least a first temperature sensor that detects an operating temperature of the crystal resonator, a second temperature sensor that detects a surrounding temperature of the container main body, and a heating resistor that applies heat to the crystal resonator, and lead wires extend from the circuit substrate and are connected electrically to the mount terminals. An insulation groove that passes through the circuit substrate in a thickness direction is formed between: a first lead wire closest to the second temperature sensor, and the second temperature sensor; and the heating resistor.

Abstract: A voltage source circuit for a crystal oscillation circuit is provided, in which the voltage source circuit and the crystal oscillation circuit are formed with the same process. The voltage source circuit includes a current source, a first PMOS, a first NMOS and a regulator unit. The current source is coupled between a voltage source and an output terminal, in which the output terminal outputs a reference voltage. Both of the gates and drains of the first PMOS and the NMOS are coupled to each other, and the first PMOS and the first NMOS are coupled between the output terminal and a ground. The regulator unit generates a work voltage to the crystal oscillation circuit as a voltage source of the crystal oscillation circuit according to the reference voltage.

Abstract: An apparatus comprising a transconductance control circuit, a boost control circuit, a current computation circuit and an oscillator circuit. The transconductance control circuit may be configured to generate a current control signal in response to (i) a voltage control signal and (ii) a plurality of range control signals. The boost control circuit may be configured to generate a current boost signal in response to a reference current signal and an enable signal. The current computation circuit may be configured to generate a first control signal and a second control signal in response to the current boost signal and the current control signal. The oscillator circuit may be configured to generate an output signal oscillating at a particular frequency in response to the first control signal and the second control signal.

Abstract: A frequency-control circuit, which is configured to receive a first signal having a first untuned frequency from a first oscillator, and to alter one or more pulses of the first signal to tune an output frequency of an output clock signal to have an average frequency at the desired target frequency. In some embodiments, the frequency-control circuit receives a signal from a single oscillator to generate a calibrated, precise, and temperature-stable clock.

Abstract: Exemplary embodiments provide a reference signal generator having a reference or center frequency within a predetermined variance over variations in temperature within a specified range. An exemplary apparatus comprises a reference resonator to generate a first reference signal having a resonant frequency, with the reference resonator having a first temperature dependence; and a plurality of switchable circuits, with at least one switchable circuit providing a second temperature dependence opposing the first temperature dependence to maintain the resonant frequency within a predetermined variance over a temperature variation.

Abstract: An electronic apparatus has a display portion, and first and second oscillating circuits each having a quartz crystal resonator, the quartz crystal resonator of each of the first and second oscillating circuits vibrating in a different mode from each other. One of the quartz crystal resonators is a quartz crystal tuning fork resonator having first and second tuning fork tines. Electrodes are disposed on side surfaces of each of the first and second tuning fork tines so that the electrodes of the first tuning fork tine have an electrical polarity opposite to an electrical polarity of the electrodes of the second tuning fork tine. The capacitance ratio r1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator is less than a capacitance ratio r2 of a second overtone mode of vibration thereof. An output signal of the oscillating circuit having the quartz crystal tuning fork resonator is a clock signal used to display time information at the display portion of the electronic apparatus.

Abstract: Dual table temperature compensation for a voltage controlled crystal oscillator is achieved by sensing the temperature of the voltage controlled crystal oscillator (VCXO), retrieving from a first table the frequency error with variations in the temperature sensed, retrieving from a second table the oscillator control voltage corresponding to the frequency error from the first table and applying the oscillator control voltage to the VCXO.

Abstract: Techniques of compensating frequency in an output in reference to a reference frequency signal are disclosed. The reference frequency signal may be from a crystal oscillator or other oscillators. Due to the changes of the temperature, the reference frequency signal drifts. According to one aspect of the techniques, a temperature frequency correction word is generated in accordance with a frequency compensation value in view of a current temperature to generate a substantially temperature compensated frequency output from a reference frequency signal. The frequency control word is produced from a successive approximation circuit configured to produce the temperature frequency correction word in accordance with the frequency compensation value in view of the current temperature. Both the temperature frequency correction word and a frequency control word are data represented in a sequence of bits. As a result, the compensated frequency output can be of high precision.

Abstract: A temperature compensated crystal oscillator is mounted to a board. A quartz resonator includes a quartz chip that generates an oscillation frequency. A resistive element is formed on the quartz chip. A temperature sensor is located closer to the board than the quartz resonator. The compensation part compensates for a change in the oscillation frequency generated by the quartz resonator based on a value of a current flowing in the resistive element and an output of the temperature sensor.

Abstract: An oscillator including a current bias circuit and a ring oscillator. The current bias circuit tracks a temperature change of the oscillator by using a control voltage and generates a plurality of bias voltages to supply a bias current according to the temperature change. The ring oscillator compares differential output signals generated according to the bias voltages and generates an oscillation signal as a result of the comparison.

Abstract: An oscillator that includes a movable element formed of silicon, the movable element vibrating by electrostatic force, a stationary element supporting the movable element, a temperature detector located in contact with the stationary element, the temperature detector detecting the temperature of the stationary element, a supporting element joined to a joint surface between the movable element and the stationary element, the supporting element supporting the movable element, the stationary element, and the temperature detector on a surface opposite to the joint surface, a surrounding element contacted with the supporting element, the surrounding element and the supporting element surround the movable element, and electrodes provided on a surface of the surrounding element opposite to a surface of surrounding element contacted with the supporting element.

Abstract: In order to decrease the temperature sensitivity of an oscillator output, and obtain a frequency of oscillation that remains stable over variations in temperature, two oscillators may be configured with identical comparators and logic circuitry, but having different oscillation frequencies. The different oscillation frequencies may be achieved by configuring each oscillator with a respective resistor divider circuit configured to adjust the reference voltage at the reference input of the respective comparator. The difference between the respective periods of oscillation of the two oscillators may therefore become independent of the comparator delay, and may only depend on temperature sensitivity of the resistor.

Abstract: A phase locked loop apparatus includes an oscillator, a variable capacitance device, a selectable capacitance device, and a capacitance controller that is configured to provide a control signal to the selectable capacitance device. The selectable capacitance device is connected to the oscillator and is responsive to the control signal such that the selectable capacitance device has a first capacitance at a first control signal value and a second capacitance at a second control signal value. The capacitance controller only selects either the first capacitance or the second capacitance by providing a control signal that has the first control signal value to select the first capacitance and having the second control signal value to select the second capacitance.

Abstract: A method and apparatus for frequency compensation for multi-band VCO have been disclosed where a VCO tank loading capacitance is adjusted slowly to allow VCO operation in a linear range.

Abstract: A temperature-compensated-resistance (TCR) circuit, which may be part of an integrated circuit, is provided. The TCR circuit consists of two resistors and a diode. The two resistors are connected in parallel and the diode is connected in series with one of the resistors. The two parallel legs of the TCR circuit may be connected to a reference voltage source, such as a ground. No specialized devices, such as bipolar transistors, Zener or Schottky diodes, or specially-processed resistors, are required by the TCR circuit. The resistors and the diode of the TCR circuit may be chosen to adjust for temperature variations in the resistance values of the resistor, leading to a negative, zero, or positive temperature coefficient of resistance for the circuit. A phase-locked loop (PLL) circuit is described as an application of the TCR circuit.

Abstract: The invention discloses a PVT-independent current-controlled oscillator, including a PV-controller, a current-controlled oscillator and a T-controller. The current-controlled oscillator is coupled to the PV-controller and outputs an oscillation frequency.

Abstract: The fundamental breakthrough in green technology are the Varactor Free Amplitude Controlled Oscillator VFACO and the planar EMI-Free Planar Inductor. The VFACO makes the fine tune for oscillation frequency. It has the frequency compensation over temperature. It doesn't have the VCO self-modulation-induced phase noise. It is phase-noiseless. It is high-Q and high stability. It increases the communication capacity. The EMI-Free Planar Inductor is the backbone of the platform of green technology. The platform of green technology contains the Xtaless ClockChip, Inductorless PMU & PA and ESDS-PCB to provide the green technology for green chip design. Especially for the 4th generation wireless communication, the Inductorless PMU & PA are the most important green technology. The Xtaless ClockChip adopts the most advanced self-compensation Amplitude controller. The ESDS-PCB has the minimum Via assignment algorithm to make the optimum pin assignment for the platform of green technology.

Abstract: An object of the invention is to provide an oven controlled crystal oscillator that prevents a reduction in characteristics due to temperature rise in the crystal vibrator and circuit elements other than the oscillating stage, and that increases energy efficiency of a heater element, to thereby facilitate temperature control.

Abstract: An automatic temperature compensated real-time clock (RTC) chip includes a clock portion having a crystal oscillator block including crystal compensation circuitry adapted to be coupled to a crystal. The crystal compensation circuitry includes a non-linear capacitor DAC including a plurality of load capacitors, wherein the load capacitors have respective switches which switch respective ones of the load capacitors to change a parallel resonance frequency (fp) generated by the oscillator block. The capacitor DAC is arranged so that Analog Trimming (ATR) bits received cause an arrangement of the switches to provide a non-linear change in overall load capacitance to result in a linear relationship between fp and the ATR bits. A temperature sensor block is coupled to the crystal for measuring a temperature of at least the crystal. An A/D converter is coupled to the temperature sensor for outputting a digital temperature signal representative of the temperature of the crystal.