Low current oscillator structure with common mode transient noise cancelation
AssigneeInfineon Technologies AG
InventorMarcus Nuebling
Life of this patent
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Abstract
Circuitry to automatically compensate a differential output oscillator circuit for common mode disturbances that may affect the oscillator output. For any differential oscillator the common mode voltage excursion may reduce the oscillator output, which in some examples may negatively affect the circuitry receiving the oscillator output. The addition of feedback circuitry with an automatic gain control, e.g., to regulate the differential output voltage, may further reduce the gain of the oscillator in the presence of common mode voltage. In contrast, the feedback circuitry of the oscillator circuit of this disclosure may include gain control circuitry to increase an output voltage amplitude at the differential output terminals for a duration of the common mode disturbance.
Claims20
A device comprising:
- an oscillator circuit including differential output terminals;
- a feedback circuit comprising a common mode detector configured to automatically control a gain of the oscillator circuit, the common mode detector:
- comprising differential input terminals connected to the differential output terminals of the oscillator circuit;
- and
- in response to sensing a common mode disturbance at the differential output of the oscillator circuit, the common mode detector is configured to automatically control the gain to increase an output voltage amplitude at the differential output terminals for a duration of the common mode disturbance.
A system comprising:
- message output circuitry;
- message receiving circuitry;
- isolated data transmission circuitry configured to receive a control signal from the message output circuitry and transmit a message based on the control signal to the message receiving circuitry, the data transmission circuitry comprising:
- an oscillator circuit comprising differential output terminals;
- a feedback circuit comprising a common mode detector configured to automatically control a gain of the oscillator circuit, the common mode detector:
- comprising differential input terminals connected to the differential output terminals of the oscillator circuit;
- and
- in response to sensing a common mode disturbance at the differential output of the oscillator circuit, the common mode detector is configured to automatically control the gain to increase an output voltage amplitude at the differential output terminals for a duration of the common mode disturbance.
A method of transmitting a message from message output circuitry over an isolation barrier to message receiving circuitry;
- the method comprising:
- receiving, by isolated data transmission circuitry, a control input from the message output circuitry,
- wherein the data transmission circuitry comprises an oscillator circuit and a feedback circuit, and
- wherein the feedback circuit comprises a common mode detector;
- controlling the oscillator circuit to turn off or to turn on based on the control input, wherein the oscillator circuit comprises differential output terminals;
- and
- in response to sensing a common mode disturbance at the differential output of the oscillator circuit, increasing, by the common mode detector of the feedback circuit, an output voltage amplitude at the differential output terminals for a duration of the common mode disturbance.
Dependencies are inferred from the claim text.