Process independent temperature sensor based on oscillator

A digital temperature sensor comprising:

• a first oscillator generating a first output signal having a first temperature characteristic;
• a second oscillator generating a second output signal having a second temperature characteristic different from the first temperature characteristic;
• and
• a time digital convertor outputting a digital signal using the first and second output signals, the digital signal indicating a temperature of the digital temperature sensor,
• wherein the first temperature characteristic of the first oscillator indicates a frequency of the first output signal that increases in proportion to an increase of the temperature and the second temperature characteristic of the second oscillator indicates a frequency of the second output signal that changes insensitively to a temperature change compared to the first temperature characteristic, and the second temperature characteristic of the second oscillator indicates the frequency of the second output signal that increases in proportion to the increase of the temperature and the first temperature characteristic of the first oscillator indicates the frequency of the first output signal that changes insensitively to the temperature change compared to the second temperature characteristic.