Oscillator circuits, current sources and methods for providing periodic frequency signals

An oscillator circuit, comprising:

• a proportional to absolute temperature (PTAT) voltage source configured to provide a voltage proportional to absolute temperature (VPTAT);
• a reference voltage source configured to provide a reference voltage;
• a resistor-capacitor (RC) element comprising a switched capacitor and at least one of a silicided resistor or a metal resistor;
• an integrator,
• wherein a first input of the integrator is configured to receive a first input signal based on the reference voltage and an output voltage of the RC element, and a second input of the integrator is configured to receive a second input signal based on the VPTAT, and
• wherein the integrator is configured to perform an integration based on a difference or a sum of the first input signal and the second input signal, and to provide an integration signal based on the integration;
• an oscillator configured to provide an output frequency signal,
• wherein the output frequency signal is controlled based on the integration signal provided by the integrator, and
• wherein the switched capacitor is controlled in a feedback loop based on the output frequency signal of the oscillator;
• at least one of a temperature sensor or a mechanical stress sensor,
• wherein the temperature sensor is configured to provide a first sensor signal representative of a temperature of the oscillator circuit, and
• wherein the mechanical stress sensor is configured to provide a second sensor signal representative of a mechanical stress of the oscillator circuit;
• and
• a processing circuit configured to adjust at least one of the reference voltage, the VPTAT, a division factor of a frequency divider, or the switched capacitor based on at least one of the first sensor signal or the second sensor signal.

A device configured to provide a temperature and mechanical stress compensated electrical current, the device comprising:

• a proportional to absolute temperature (PTAT) voltage source configured to provide a voltage proportional to absolute temperature (VPTAT), wherein the PTAT voltage source comprises at least one of a silicided polysilicon resistor or a metal resistor;
• at least one of a temperature sensor or a mechanical stress sensor,
• wherein the temperature sensor is configured to provide a first sensor signal representative of a temperature of an oscillator circuit, and
• wherein the mechanical stress sensor is configured to provide a second sensor signal representative of a mechanical stress of the oscillator circuit;
• and
• a processing circuit configured to adjust at least one of a reference voltage, the VPTAT, a division factor of a frequency divider, or a switched capacitor based on at least one of the first sensor signal or the second sensor signal.

A method for providing a periodic frequency signal, the method comprising:

• providing a first electrical current using a temperature and mechanical stress compensated current source;
• providing a second electrical current using a switched capacitor;
• performing an integration based on a difference of the first electrical current and the second electrical current using an integrator, thereby providing an integration signal based on the integration;
• controlling an output frequency signal provided by an oscillator based on the integration signal;
• controlling the second electrical current provided by the switched capacitor based on the output frequency signal provided by the oscillator;
• and
• adjusting at least one of a reference voltage, a voltage proportional to absolute temperature (VPTAT), a division factor of a frequency divider, or the switched capacitor based on at least one of a first sensor signal or a second sensor signal,
• wherein the first sensor signal is representative of a temperature of the oscillator, and is provided by a temperature sensor, and
• wherein the second sensor signal is representative of a mechanical stress of the oscillator, and is provided by a mechanical stress sensor.