Temperature compensated crystal oscillator
First Claim
1. An integrated circuit for a temperature compensated crystal oscillator having an external crystal, the circuit comprisingan internal temperature sensor,a temperature compensator having one fixed or at least two selectable 3rd and/or 4th and/or 5th and/or higher order temperature compensation functions for at least one specific type of external crystal, andcalibrator circuitry for the temperature compensator, said calibrator circuitry being configured to be connected an external voltage or current source for calibration procedure of the temperature compensator, said external voltage or current source overdriving a respective temperature-dependent voltage or current supplied from said internal temperature sensor to the temperature compensator, whereby enabling the calibration procedure to be performed at one temperature without use of temperature variation.
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Abstract
The present invention relates to an integrated circuit for a temperature compensated crystal oscillator having an external crystal. The integrated circuit comprises a temperature compensation having one fixed or at least two selectable 3rd and/or 4th and/or 5th and/or higher order temperature compensation functions for at least one specific type of external crystal. The temperature compensation can be calibrated at one temperature, in other words without use of temperature variation, by means of an external voltage or current source overdriving a respective temperature-dependent voltage or current supplied from an internal temperature sensor to the temperature compensation.
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Citations
10 Claims
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1. An integrated circuit for a temperature compensated crystal oscillator having an external crystal, the circuit comprising
an internal temperature sensor, a temperature compensator having one fixed or at least two selectable 3rd and/or 4th and/or 5th and/or higher order temperature compensation functions for at least one specific type of external crystal, and calibrator circuitry for the temperature compensator, said calibrator circuitry being configured to be connected an external voltage or current source for calibration procedure of the temperature compensator, said external voltage or current source overdriving a respective temperature-dependent voltage or current supplied from said internal temperature sensor to the temperature compensator, whereby enabling the calibration procedure to be performed at one temperature without use of temperature variation.
Specification