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).

A frequency synthesizer on an integrated circuit provides a local oscillator (LO) signal for RF operations and also functions as an injection clock signal source during crystal oscillator startup. The integrated circuit goes into a sleep mode in which the crystal oscillator is off and responsive to a wakeup event the crystal oscillator starts up again using the injection clock signal sourced from the frequency synthesizer. Parameters that cause the injection clock signal to match the crystal oscillator frequency are stored. The frequency synthesizer includes a phase-locked loop having an LC oscillator. A digital to analog converter controls the LC oscillator during injection. During an initial power up of the integrated circuit, a PLL in the frequency synthesizer locks to the crystal oscillator frequency to determine the parameters to store for injection.

A frequency synthesizer on an integrated circuit provides a local oscillator (LO) signal for RF operations and also functions as an injection clock signal source during crystal oscillator startup. The integrated circuit goes into a sleep mode in which the crystal oscillator is off and responsive to a wakeup event the crystal oscillator starts up again using the injection clock signal sourced from the frequency synthesizer. Parameters that cause the injection clock signal to match the crystal oscillator frequency are stored. The frequency synthesizer includes a phase-locked loop having an LC oscillator. A digital to analog converter controls the LC oscillator during injection. During an initial power up of the integrated circuit, a PLL in the frequency synthesizer locks to the crystal oscillator frequency to determine the parameters to store for injection.

The present disclosure relates to an electronic device comprising a first capacitor and a quartz crystal coupled in series between a first node and a second node; an inverter coupled between the first and second nodes; a first variable capacitor coupled between the first node and a third node; and a second variable capacitor coupled between the second node and the third node.

A system includes a power driver, configured to generate an electric excitation; an oscillating system, configured to perform an oscillation induced by the electric excitation; a feedback detector, configured to detect a feedback measurement signal with to the oscillation; and a controller configured to operate: in a closed loop mode, to control the power driver to generate the electric excitation as a discontinuous electric excitation according to timing information obtained from the detected feedback measurement signal, to synchronize the discontinuous electric excitation with the detected feedback measurement signal; in a learning mode preceding the closed loop mode, to control the power driver to generate the electric excitation as a continuous electric excitation, to obtain timing information from the feedback measurement signal to be used, at least once, in the subsequent closed loop mode, to synchronize the discontinuous electric excitation with the detected feedback measurement signal.

A system includes a power driver, configured to generate an electric excitation; an oscillating system, configured to perform an oscillation induced by the electric excitation; a feedback detector, configured to detect a feedback measurement signal with to the oscillation; and a controller configured to operate: in a closed loop mode, to control the power driver to generate the electric excitation as a discontinuous electric excitation according to timing information obtained from the detected feedback measurement signal, to synchronize the discontinuous electric excitation with the detected feedback measurement signal; in a learning mode preceding the closed loop mode, to control the power driver to generate the electric excitation as a continuous electric excitation, to obtain timing information from the feedback measurement signal to be used, at least once, in the subsequent closed loop mode, to synchronize the discontinuous electric excitation with the detected feedback measurement signal.

A method of operating an oscillator circuit comprising a resonator is provided. The method comprises maintaining a resonance of the resonator by a) connecting the resonator to an input voltage (V.sub.buf) for a first pulse period to charge the resonator only partially towards the input voltage (V.sub.buf); b) connecting the resonator to a second, lower, voltage for a second pulse period to discharge the resonator at least partially; and repeating steps a) and b) at a rate corresponding to the resonance of the resonator and with a phase corresponding to the resonance of the resonator, so as to maintain the resonance of the resonator.

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).

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 disclosure relates to an electronic device comprising a first capacitor and a quartz crystal coupled in series between a first node and a second node; an inverter coupled between the first and second nodes; a first variable capacitor coupled between the first node and a third node; and a second variable capacitor coupled between the second node and the third node.