Apparatus and methods for generating multiple oscillating signals. An example circuit generally includes a first voltage-controlled oscillator (VCO) circuit and a second VCO circuit having a differential bias input coupled to a differential output of the first VCO circuit. At least one of the first VCO circuit or the second VCO circuit generally includes: a pair of cross-coupled transistors comprising a first transistor and a second transistor, a first inductive element coupled between a first node and the drain of the first transistor, a second inductive element coupled between the first node and the drain of the second transistor, a third transistor having a drain coupled to the drain of the first transistor and having a source coupled to a second node, and a fourth transistor having a drain coupled to the drain of the second transistor and having a source coupled to the second node.

An apparatus for communicating across an isolation barrier includes a differential pair of input terminals. The apparatus includes a bandpass filter circuit configured to receive a received signal on the differential pair of input terminals and to provide a received differential signal on a differential pair of nodes. The apparatus includes a demodulator directly coupled to the bandpass filter circuit and configured to directly demodulate the received differential signal on the differential pair of nodes to provide a demodulated received signal.

Described is a high Q-factor inductor. The inductor is formed as a unit cell coil, which is copied twice for a dual-coil inductor and copied four times for a quad-coil inductor. For each copy of the unit cell coil, the coil is rotated a subsequent substantially 90 degrees or substantially −90 degrees. The rotation enables the terminals of the inductor to be routed equal-distant to a circuit that is placed in the line of symmetry between the two coils.

A method for detecting an RF signal detected by a super-regenerative receiver (1). The receiver includes a reference oscillator (4) for generating an oscillation in the oscillator, a bias current generator (7) for supplying a bias current, an oscillation detector (6) connected between an output (coilp) of the oscillator and the bias current generator for controlling when an RF signal is received by the receiver, and an impedance matching unit (3) disposed between the input of the receiver and the reference oscillator (4). Following activation of a start control signal, detection of the oscillation of the reference oscillator is performed, and once the reference oscillator oscillates above a critical increasing bias current value, the oscillation detector orders the bias current generator to cut off the bias current and thus stop the oscillation of the reference oscillator to reduce the overall electricity consumption during an RF signal detection phase.

A method is provided for enhancing the detection of the start time of a reference oscillator (4) of a super-regenerative receiver (1), which includes the reference oscillator, a bias current generator (7), an oscillation detector (6), and an impedance matching unit (3). Following the supply of the bias current (i_vco) after receiving the activation control signal (Sosc), an oscillation detection is performed by the oscillation detector (6), and once oscillation is detected, an additional amplification current (iboost) dependent on the envelope of the detected oscillation, of an amplification current generation circuit is supplied to the reference oscillator (4) in addition to the bias current to amplify the oscillation signal to be above a critical oscillation start threshold so as to precisely define the start time of the oscillator, and enable the oscillation detector (6) to order the stoppage of oscillation of the reference oscillator (4).

The present invention provides an oscillator including a tapped inductor and a cross-coupled pair. The tapped inductor includes a first terminal, a second terminal, a first tap and a second tap. The cross-coupled pair receives two input signals from the first terminal and the second terminal to generate two output signals to the first tap and the second tap, respectively.

An oscillator circuit includes a first BAW oscillator, a first coupling stage, a second BAW oscillator, and a second coupling stage. The first BAW oscillator is configured to generate a first output signal at a frequency. The first coupling stage is coupled to the first BAW oscillator, and is configured to amplify the first output signal. The second BAW oscillator is coupled to the first coupling stage, and is configured to generate a second output signal at the frequency. The second output signal differs in phase from the first output signal. The second coupling stage is coupled to the first BAW oscillator and the second BAW oscillator, and is configured to amplify the second output signal and drive the first BAW oscillator.

An oscillator is provided. The oscillator includes two reverse amplification elements, and each of the reverse amplification elements forms a self-feedback structure by using an inductor. Output ends of the two reverse amplification elements are coupled to each other by using one or more inductors, and input ends of the two reverse amplification elements are coupled to each other by using a capacitor. A capacitance value of the capacitor may be adjusted, to change an oscillation frequency of a differential output oscillation signal output by the oscillator.

Voltage-controlled oscillation circuitry includes multiple cores and multiple mode or gain boosters coupled between the multiple cores. To prevent an undesired operating mode of the voltage-controlled oscillation circuitry from dominating a desired operating mode (e.g., an in-phase operating mode or an out-of-phase operating mode), the mode boosters may increase a desired gain of the desired operating mode and decrease an undesired gain of the undesired operating modes. In particular, mode boosters coupled to terminals of the cores that are associated with the desired operating mode may be enabled, while mode boosters coupled to terminals of the cores that are associated with the undesired operating mode may be disabled.

A DC-DC converter includes: an transformer having a primary winding and a secondary winding magnetically coupled to the primary winding; a power oscillator applying an oscillating signal to the primary to transmit a power signal to the secondary winding; a rectifier connected to the secondary winding of the transformer to obtain an output DC voltage by rectification of the power signal; comparison circuitry to generate an error signal representing a difference between the output DC voltage and a reference voltage; a transmitter connected to the secondary winding of the transformer to apply an amplitude modulation to the power signal at the secondary winding of the transformer in response to the error signal to thereby produce an amplitude modulated signal at the primary winding; and a receiver and control circuit connected to the primary winding to control an amplitude of the oscillating signal as a function of the amplitude modulated signal.