On-chip temperature detection using an oscillator
View Patent ↗A temperature detection circuit on an integrated circuit has a temperature sensitive oscillator, at least one temperature insensitive oscillator, a reference clock, process detection circuitry coupled to an output of the temperature insensitive oscillator and the output of the reference clock, the process detection circuitry to compare the outputs and produce a process signal, and temperature reference circuitry coupled to an output of the temperature sensitive oscillator, the output of the reference clock, and the process signal, the temperature detection circuitry to produce a temperature for the integrated circuit.
1. A temperature detection circuit on an integrated circuit, comprising:
a temperature sensitive oscillator;
at least one temperature insensitive oscillator;
a reference clock;
process detection circuitry coupled to an output of the temperature insensitive oscillator and the output of the reference clock, the process detection circuitry to compare the outputs and produce a process corner signal indicating a process corner to which the integrated circuit belongs; and
temperature reference circuitry coupled to an output of the temperature sensitive oscillator, the output of the reference clock, and the process corner signal, the temperature detection circuitry to produce a temperature for the integrated circuit.
2. The temperature detection circuitry of claim 1 , wherein the at least one temperature insensitive oscillator comprises two temperature insensitive oscillators.
3. The temperature detection circuitry of claim 2 , wherein the two temperature insensitive oscillators comprise one CMOS P oscillator and one CMOS N oscillator.
4. The temperature detection circuitry of claim 2 , wherein the process detection circuitry couples to the output of the two temperature insensitive oscillators through counters.
5. The temperature detection circuitry of claim 1 , wherein the temperature sensitive oscillator comprises a CMOS PN oscillator.
6. The temperature detection circuitry of claim 1 , wherein the temperature sensitive oscillator couples to the temperature reference circuitry through a counter.
7. The temperature detection circuitry of claim 1 , further comprising a voltage regulator coupled to the temperature sensitive oscillator and the temperature insensitive oscillator.
8. The temperature detection circuitry of claim 1 , wherein the temperature reference circuitry couples to the reference clock through a counter.
9. The temperature detection circuitry of claim 1 , wherein the temperature reference circuitry comprises:
a comparator to compare the output of the temperature sensitive oscillator and the reference clock to produce a temperature sensitivity signal; and
a look up table of temperatures, wherein the process corner signal is used to access an appropriate temperature look up table to determine a temperature for the integrated circuit.
10. A method of classifying an integrated circuit, comprising:
operating at least one temperature insensitive oscillator at a steady state;
counting an output of the temperature insensitive oscillator to produce a temperature insensitive count;
counting an output of a reference clock to produce a reference count;
comparing the reference count to the temperature insensitive count; and
using the comparison to determine a process corner by which the integrated circuit is classified.
11. The method of claim 10 , further comprising operating a temperature sensitive oscillator at a steady state.
12. The method of claim 11 , further comprising comparing an output of the temperature sensitive oscillator to the reference clock.
13. The method of claim 10 , further comprising using the process corner by which the integrated circuit is classified and the comparison between the temperature sensitive oscillator to the reference clock to determine a temperature for the integrated circuit.