Oscillator circuit
AssigneeEM Microelectronic-Marin SA
InventorJiri Nerad
Life of this patent
Estimating the term…
Abstract
The disclosure concerns an oscillator circuit (10) for a signal transmitter, the oscillator circuit (10) comprising: a resonant circuit (12) comprising a resonant inductor (LR) and a resonant capacitor (CR) parallel to the resonant inductor (LR) or comprising a crystal device, a driving branch (14) comprising a pump capacitor (CP) connected to the resonant circuit (12), a feedback branch (20) connected to the resonant circuit (12), a phase shifting circuit (22) connected to the resonant circuit (12) via the feedback branch (20), a comparator circuit (24) connected to the feedback branch (20) via the phase shifting circuit (22) and a driver circuit (28) connected to an output of the comparator circuit (24) and operable to charge the pump capacitor (CP).
Claims14
An oscillator circuit for a signal transmitter, the oscillator circuit comprising:
- a resonant circuit comprising a resonant inductor connected between an oscillator output and ground and a resonant capacitor connected between the oscillator output and ground, that is parallel to the resonant inductor,
- a driving branch comprising a pump capacitor connected to the oscillator output, and connected to the resonant capacitor and the resonant inductor of the resonant circuit,
- a feedback branch connected to the resonant circuit, via a feedback divider connected between the oscillator output and ground, and connected in parallel to the resonant circuit, wherein the feedback divider comprises a feedback capacitor connected in series with a ground capacitor between the oscillator output and ground, and wherein the feedback branch is connected to the resonant circuit via a feedback node located to the connection of the feedback capacitor and the ground capacitor,
- a phase shifting circuit connected to the resonant circuit via the feedback branch, wherein the phase shifting circuit comprises a RC bridge circuit having an input terminal connected to the feedback branch and having a differential output comprising two output terminals connected to two signal nodes,
- a voltage comparator circuit connected to the feedback branch via the RC bridge circuit of the phase shifting circuit, wherein two differential input terminals of the comparator circuit are connected to the two signal nodes driven by the two differential output terminals of the RC bridge circuit and wherein the voltage comparator circuit is operable to compare the voltages at the two signal nodes, and
- a driver circuit comprising an input terminal driven by the output of the voltage comparator circuit and operable to charge the resonant capacitor via the pump capacitor.
A method of generating an oscillation of an oscillator circuit comprising a resonant circuit, the method comprising the steps of:
- sensing a feedback signal from the resonant circuit via a feedback branch,
- phase shifting the feedback signal by a phase shifting circuit connected to the resonant circuit via the feedback branch,
- transferring the phase shifted feedback signal into a logic signal by a comparator circuit and
- applying the logic signal to a driver circuit operable to charge a resonant capacitor of the resonant circuit via a pump capacitor in a driving branch of the resonant circuit.
An oscillator circuit for a signal transmitter, the oscillator circuit comprising:
- a resonant circuit connected between an oscillator output and ground,
- a driving branch comprising a pump capacitor connected to the oscillator output and connected to the resonant circuit,
- a feedback branch connected to the resonant circuit, via a feedback divider connected between the oscillator output and ground, and connected in parallel to the resonant circuit, wherein the feedback divider comprises a feedback capacitor connected in series with a ground capacitor between the oscillator output and ground, and wherein the feedback branch is connected to the resonant circuit via a feedback node located to the connection of the feedback capacitor and the ground capacitor,
- a phase shifting circuit connected to the resonant circuit via the feedback branch, wherein the phase shifting circuit comprises a RC bridge circuit having an input terminal connected to the feedback branch and having a differential output comprising two output terminals connected to two signal nodes,
- a voltage comparator circuit connected to the feedback branch via the RC bridge circuit of the phase shifting circuit, wherein two differential input terminals of the comparator circuit are connected to the two signal nodes driven by the two differential output terminals of the RC bridge circuit and wherein the voltage comparator circuit is operable to compare the voltages at the two signal nodes, and
- a driver circuit comprising an input terminal driven by the output of the voltage comparator circuit and operable to charge the resonant circuit via the pump capacitor.
Dependencies are inferred from the claim text.