Temperature compensated oscillation circuits

Abstract

A temperature compensated oscillation circuit capable of providing a stable frequency output over temperature is provided, in which an oscillator with a crystal resonator is arranged to generate an oscillation signal with an output frequency, and a temperature sensor provides a temperature compensation voltage of which a function is linear with respect to an ambient temperature of the oscillator. A first accumulation mode MOS varactor is coupled to the oscillator, and the first accumulation mode MOS varactor adjusts a capacitance thereof in response to the temperature compensation voltage, such that the coupled oscillator has a frequency compensation over temperature for the oscillation signal, wherein the frequency compensation substantially varies as an inverse function of a deviation of the crystal resonator over temperature when the ambient temperature is within a predetermined temperature range.

Dependencies are inferred from the claim text.