Time domain digital temperature sensing system and method thereof

A digital temperature sensing system for converting a test temperature into a digital output signal, the system comprising:

• a temperature-to-time circuit for generating a thermally sensitive time signal of which a width varies with the test temperature;
• an adjustable time reference circuit having a digital input terminal for receiving a digital set value from the digital input terminal and generating a time reference signal of which a width changes with the digital set value;
• a time comparator receiving the thermally sensitive time signal and the time reference signal for generating a time comparison signal according to the width difference between the thermally sensitive time signal and the time reference signal;
• a logic control circuit receiving the time comparison signal for adjusting the digital set value of the adjustable time reference circuit according to the time comparison signal so that the width of the thermally sensitive time signal and the width of time reference signal are close enough or substantially equal;
• and
• a digital output terminal electrically connected to the digital input terminal of the adjustable time reference circuit for providing the digital output signal to be an output of the digital temperature sensing system.