Patent ID: 8248171

Claim:
A thermally-compensated oscillator, comprising: a current reference having an output current which has a first relationship to an ambient temperature; at least one ring oscillator having an operating frequency which has a second relationship to the ambient temperature, and which receives the output current of the current reference and in response outputs an oscillator signal; and a level shifter which receives the oscillator signal from the ring oscillator and outputs a corresponding voltage-regulated clock signal, wherein the current reference includes a first grounded MOSFET transistor and a second grounded MOSFET transistor, the first MOSFET transistor and the second MOSFET transistor being gate-coupled, and a source of the second MOSFET transistor being grounded via a resistance which has a third relationship to the ambient temperature, wherein the current reference further comprises: a third MOSFET transistor and a fourth MOSFET transistor, the third and the fourth MOSFET transistors being gate-coupled and supplying the output current to the ring oscillator, wherein the first and second MOSFET transistors are of a same channel type, and the third and fourth MOSFET transistors are of an opposite channel type to the first and second MOSFET transistors.