A quadrature oscillation circuit includes a plurality of adjacent quadrature oscillators, wherein a first quadrature oscillator includes a first I-phase inductor, a first Q-phase inductor, and a first drive circuit that generates a first I-phase current passing the first I-phase inductor and a first Q-phase current passing the first Q-phase inductor such that phases of a first I-phase differential signal from the first I-phase inductor are different from phases of a first Q-phase differential signal from the first Q-phase inductor, a second quadrature oscillator includes a second I-phase inductor, a second Q-phase inductor, and a second drive circuit that generates a second I-phase current passing the second I-phase inductor and a second Q-phase current passing the second Q-phase inductor such that phases of a second I-phase differential signal from the second I-phase inductor are different from phases of a second Q-phase differential signal from the second Q-phase inductor.

A quadrature oscillation circuit includes a plurality of adjacent quadrature oscillators, wherein a first quadrature oscillator includes a first I-phase inductor, a first Q-phase inductor, and a first drive circuit that generates a first I-phase current passing the first I-phase inductor and a first Q-phase current passing the first Q-phase inductor such that phases of a first I-phase differential signal from the first I-phase inductor are different from phases of a first Q-phase differential signal from the first Q-phase inductor, a second quadrature oscillator includes a second I-phase inductor, a second Q-phase inductor, and a second drive circuit that generates a second I-phase current passing the second I-phase inductor and a second Q-phase current passing the second Q-phase inductor such that phases of a second I-phase differential signal from the second I-phase inductor are different from phases of a second Q-phase differential signal from the second Q-phase inductor.

In accordance with an embodiment, a voltage controlled oscillator (VCO) includes a VCO core having a plurality of transistors and a varactor circuit that has a first end coupled to emitter terminals of the VCO core and a second end coupled to a tuning terminal. The varactor circuit includes a capacitance that increases with increasing voltage applied to the tuning terminal with respect to the emitter terminals of the VCO core.

A system includes a sensor integrated circuit (IC), including a driver adapted to be coupled to an oscillator, the driver including first and second transistors. The sensor IC includes an amplitude control amplifier coupled to the first transistor. The sensor IC also includes a common mode control amplifier coupled to the second transistor. The sensor IC includes a handover control circuit coupled to the amplitude control amplifier and configured to hand off an operation from the sensor IC to a different sensor IC, the handover control circuit including a resistor network coupled to a switch network.

An apparatus for temperature sensing may include: a bias generator suitable for generating a complementary-to-absolute-temperature (CTAT) bias voltage; a regulator suitable for regulating a bias voltage by using CTAT bias voltage and outputting a regulated bias voltage; and a ring oscillator suitable for receiving the regulated bias voltage and generating an oscillation signal based on the regulated bias voltage.

An oscillation signal generation circuit includes an oscillator and a calibration circuit. The oscillator includes a reference signal source circuit that has a reference signal source outputting a reference signal and converts the output reference signal into a control voltage, a filter that includes a variable resistance and a capacitance and removes noise in the control voltage, a transistor that converts the control voltage which has passed through the filter into a control current and outputs the control current, a core circuit that is driven by the control current and generates an output signal, and an output terminal that outputs the generated output signal. The calibration circuit is connected to the output terminal of the oscillator, detects whether or not the generated output signal is oscillating, and adjusts the current value of the control current by controlling the resistance value of the variable resistance in accordance with the detection result.

A voltage controlled oscillator (VCO) comprising a first supply node, a second supply node, an oscillation transistor, a biasing network, an output node and a feedback network is described. The VCO is be powered by a supply voltage applied across the first and second supply nodes. The oscillation transistor and the biasing network are connected in series between the first supply node and the second supply node. The output node is connected to the oscillation transistor so as to deliver an oscillatory output signal. The feedback network provides an oscillatory feedback signal from the output node to the biasing network. The feedback network comprises a capacitive element and a transmission line connected in series for transferring the feedback signal. The VCO may be integrated in a radar device, for example.

A two-walled coupled inductor includes an outer wall and an inner wall separated by a slit. The outer wall has a first width and the inner wall has a second width. The inner wall and the outer wall may be configured to be coupled to oscillator circuitry. The two-walled coupled inductor may include an electrically conductive stub coupled to the outer wall to be coupled to a power supply. A common mode current flows through the outer wall, and the stub if one is present, and a differential mode current flows through both the outer wall and the inner wall, but not the stub. The first and second widths, and dimensions of the stub, may be sized to increase an inductance of the common mode compared to an inductance of the differential mode, thereby reducing phase noise of the inductor-based resonator.

A two-walled coupled inductor includes an outer wall and an inner wall separated by a slit. The outer wall has a first width and the inner wall has a second width The inner wall and the outer wall may be configured to be coupled to oscillator circuitry. The two-walled coupled inductor may include an electrically conductive stub coupled to the outer wall to be coupled to a power supply. A common mode current flows through the outer wall, and the stub if one is present, and a differential mode current flows through both the outer wall and the inner wall, but not the stub. The first and second widths, and dimensions of the stub, may be sized to increase an inductance of the common mode compared to an inductance of the differential mode, thereby reducing phase noise of the inductor-based resonator.

A circuit includes an error amplifier including a reference input, a feedback input, and an error output. A compensation network has a frequency input and a compensation output, in which the compensation output is coupled to the error output. The compensation network configured to provide a variable capacitance between the compensation output and a ground terminal based on a frequency signal at the frequency input having a value representative of a frequency of a clock signal.