A circuit device includes: an oscillation circuit configured to oscillate a resonator; a temperature compensation circuit configured to output a temperature compensation voltage for temperature compensating an oscillation frequency of the oscillation circuit, based on a temperature detection result of a temperature sensor; and a frequency control circuit configured to output a frequency control voltage for the oscillation frequency. The oscillation circuit includes a first variable capacitance circuit having a positive capacitance change characteristic with respect to a capacitance control voltage and a second variable capacitance circuit having a negative capacitance change characteristic with respect to the capacitance control voltage. The temperature compensation circuit supplies the temperature compensation voltage as the capacitance control voltage to the first variable capacitance circuit, and the frequency control circuit supplies the frequency control voltage as the capacitance control voltage to the second variable capacitance circuit.

A circuit device includes an oscillation circuit that generates an oscillation signal by using a vibrator, a frequency adjustment circuit that adjusts an oscillation frequency of the oscillation circuit based on frequency adjustment data, a temperature sensor circuit that outputs temperature data, an arithmetic operation circuit, and a storage circuit. The arithmetic operation circuit outputs converted temperature data by performing, on the temperature data, conversion processing in which a slope of the converted temperature data with respect to the temperature data in a first temperature range is different from a slope of the converted temperature data with respect to the temperature data in a second temperature range. The storage circuit stores a lookup table representing a correspondence between the converted temperature data and the frequency adjustment data.

Disclosed are a crystal oscillator, a chip, and an electronic device. The crystal oscillator includes: an oscillating circuit, including: a crystal, an amplification circuit, a first load capacitor, and a second load capacitor, where the first load capacitor and the second load capacitor are respectively connected to a first terminal and a second terminal of the crystal; and a first Miller multiplication circuit, where an input terminal and an output terminal of the first Miller multiplication circuit are respectively connected to two terminals of the first load capacitor, and the first Miller multiplication circuit is configured to increase a first load capacitance of the oscillating circuit, where the first load capacitance is a capacitance between the first terminal of the crystal and the ground. According to this technical solution, an area occupied by the load capacitor as well as circuit costs can be reduced.

The digital-output temperature sensor includes a temperature sensor circuit, a current mirror circuit which makes a mirror current of a temperature detection current flow and pulls in a mirror current of a reference current to thereby output a first difference current from a first output node and output a second difference current from a second output node, a chopping circuit, and an A/D conversion circuit. The chopping circuit performs a chopping operation of making the mirror current of the reference current flow in a second state through a transistor of the current mirror circuit through which the mirror current of the temperature detection current flows in a first state, and making the mirror current of the temperature detection current flow in the second state through the transistor of the current mirror circuit through which the mirror current of the reference current flows in the first state.

A circuit device includes an oscillation circuit and a processing circuit that generates capacitance control data. The oscillation circuit includes a variable capacitance circuit whose capacitance value is variably controlled based on the capacitance control data, and an oscillation frequency thereof is controlled based on the capacitance value of the variable capacitance circuit. The variable capacitance circuit includes a capacitor array. The capacitor array includes a plurality of capacitors each having a binary-weighted capacitance value, and a plurality of switches that are on-off controlled based on the capacitance control data. The processing circuit outputs the capacitance control data, which is subjected to dithering, so as to switch the capacitance value of the variable capacitance circuit between a first capacitance value and a second capacitance value in a time division manner.

A fast start-up crystal oscillator (XO) and a fast start-up method thereof are provided. The fast start-up XO may include a XO core circuit, a frequency synthesizer, and a fast start-up interfacing circuit, wherein the frequency synthesizer may include a voltage control oscillator (VCO) and a divider. The XO core circuit generates a XO signal having a XO frequency. The VCO generates a VCO clock having a VCO frequency, and the divider generates a divided clock having a divided frequency, wherein the VCO frequency is divided by a divisor of the divider to obtain the divided frequency. The fast start-up interfacing circuit transmits the divided clock to the XO core circuit, and then generates a reference clock having the XO frequency according to the XO signal. More particularly, the VCO frequency is calibrated according to the reference clock, in order to make the divided frequency approach the XO frequency.

A variable capacitance circuit includes a capacitor array having a first capacitor in which a plurality of MIM capacitors are coupled in parallel and a second capacitor in which a plurality of MIM capacitors are coupled in series, and a switch array having a first switch and a second switch. A shape pattern of at least one of a first electrode of the first capacitor, a first ground shield, a second electrode of the second capacitor, and a second ground shield is set so that a first capacitance difference per 1 LSB between first capacitance values of the first capacitor when the first switch is turned on and off and a second capacitance difference per 1 LSB between second capacitance values of the second capacitor when the second switch is turned on and off are close to each other.

Both parallel-type and serial-type dual-mode oscillators employing stress compensated cut resonators having various configurations are disclosed. Both classes of dual-mode oscillators employ multiple tank circuits to pass one frequency of the resonator and block the other frequency. The tank circuits isolate the operation of the two oscillator sub-circuits that form the dual-mode oscillator from one another. The dual-mode oscillators may be implemented with either bipolar or CMOS transistors. The parallel-type dual-mode oscillators employ inverters to provide gain. The serial-type dual-mode oscillators employ a two (or three) stage design including a follower circuit first stage and an inverting amplifier/limiter circuit second stage, with an optional intervening transimpedance amplifier stage.

A nanoelectromechanical systems (NEMS) oscillator network and methods for its operation are disclosed. The NEMS oscillator network includes one or more network inputs configured to receive one or more input signals. The NEMS oscillator network also includes a plurality of NEMS oscillators coupled to the one or more network inputs. Each of the plurality of NEMS oscillators includes a NEMS resonator and produces a radio frequency (RF) output signal that oscillates at a particular frequency and a particular phase. The NEMS oscillator network further includes a plurality of connections that interconnect the plurality of NEMS oscillators. The NEMS oscillator network further includes one or more network outputs coupled to the plurality of NEMS oscillators and configured to output one or more output signals.

A circuit device includes an oscillation circuit generating an oscillation signal by oscillating a vibrator, a temperature sensor circuit performing an intermittent operation, a logic circuit performing temperature compensation processing based on an output of the temperature sensor circuit, and a power supply circuit supplying power to the oscillation circuit. The oscillation circuit is disposed in a circuit region, the temperature sensor circuit and the logic circuit are disposed in a circuit region, and the power supply circuit is disposed in a circuit region, which is positioned between the circuit region and the circuit region.