A voltage controlled oscillator is provided. The voltage controlled oscillator includes a current controlled oscillator, a voltage to current conversion circuit and a noise cancellation circuit. The current controlled oscillator is configured to receive a bias current and generate an oscillating signal with an oscillating frequency according to the bias current. The voltage to current conversion circuit is coupled to a power supply voltage and configured to generate a supply current according to an input voltage. The noise cancellation circuit is configured to receive a bias voltage and the supply current from the voltage to current conversion circuit, and configured to generate a noise cancellation current in response to power supply voltage variation and cancel the noise cancellation current from the supply current to generate the bias current. The bias voltage of the noise cancellation circuit is coupled to an internal voltage of the voltage to current conversion circuit.

An oscillator configured to generate an oscillation signal is provided. The oscillator includes a transistor pair and a cross-coupled transistor pair. The transistor pair is coupled to a first current source and has a first transconductance. The first transconductance is changed in response to a current value of the first current source. The cross-coupled transistor pair is coupled to a second current source and has a second transconductance. The second transconductance is changed in response to a current value of second current source. The transistor pair and the cross-coupled transistor pair are mutually coupled by a plurality of inductors. A frequency of the oscillation signal is determined according to the first transconductance and the second transconductance. Furthermore, a clock generator and a method for generating a clock signal thereof are also provided.

A crystal oscillator circuit that can be controlled for fast start-up and for efficient operation is disclosed. The control includes adjusting a voltage applied to a body terminal of a transistor in order to control the amplification of the crystal oscillator. The amplification can be increased, relative to a motional resistance of the crystal oscillator, at start-up to reduce a start-up time necessary for oscillation. The amplification can also be decreased in order to maintain oscillation after start-up more efficiently. In some implementations, the transistor for control is a fully depleted silicon on insulator (FDSOI) transistor that accommodates a wide range of body bias voltages.

A digitally controlled oscillator (DCO) includes; a current mirror configured to generate a supply current in response to a bias voltage matching a reference current, a variable resistor connected to the current mirror through a first node outputting the reference current and configured to provide a variable resistance in response to a first control signal, an oscillation circuit connected to the current mirror through a second node outputting the supply current and configured to generate an oscillation signal in response to the supply current, and a feedback circuit configured to control the bias voltage in relation to at least one of a voltage at the first node and a voltage at the second node.

An oscillator circuit includes an oscillating circuit coupled to a vibrator, and a control circuit that controls the oscillating circuit. The oscillator circuit has a normal operation mode in which the oscillating circuit oscillates in a state where a negative resistance value is a first value, and a start mode in which the oscillator circuit shifts from a state where oscillation is stopped to the normal operation mode. In the start mode, the control circuit controls the negative resistance value to increase from a second value which is smaller than the first value.

A method of manufacturing an oscillator including housing a first resonator and a first integrated circuit device configured to oscillate the first resonator in a first container to manufacture the first oscillator, and housing a second resonator and a second integrated circuit device configured to oscillate the second resonator in a second container to manufacture the second oscillator, wherein the first integrated circuit device includes a first oscillation circuit configured to oscillate the first resonator to output a first oscillation signal, and no PLL circuit, the second integrated circuit device includes a second oscillation circuit configured to oscillate the second resonator to output a second oscillation signal, and a PLL circuit to which the second oscillation signal is input, and which is configured to output a third oscillation signal, and the first container and the second container are containers same in type.

A CMTI circuit includes a first detector that receives one or more output signals from an oscillator and a first enable signal and generates a first detection signal when the received output signals are determined to be substantially not oscillating at a first time. The CMTI circuit further includes a first activation signal generator that generates a first activation signal in response to the first detection signal to resume oscillation of the output signals.

A current generating circuit includes a current generator configured to supply a reference current, switches connected to the current generator, wherein one switch of the switches is selected and configured to operate, according to a switch selection signal, and one or more resistors, respectively connected to the switches, wherein a rate of current change according to a temperature change of the current generator is adjusted based on a temperature coefficient of resistance (TCR) of resistors connected to the one switch, according to adjustment of the one switch.

The present invention relates to an active shunt capacitance cancelling oscillator circuit. Such systems can be used in resonator-based methods, while avoiding impedance distortion and phase shift anomalies.

Examples of increasing yield and operating temperature range of transmitters are disclosed. In one example, a transmitter has an a thin-film bulk acoustic (FBAR) resonator. The transmitter may be a Bluetooth Low Energy (BLE) transmitter. In this example, the FBAR-based BLE transmitter does not require or have a phase locked loop, and does not require or have a crystal reference. The FBAR-based BLE transmitter may have an oscillator with a split capacitor array. The oscillator may be a Pierce oscillator with a split capacitor array. The FBAR-based transmitter and calibration methods described herein provide a greater yield and wider operating range than prior transmitters.