Patent ID: 6908227

Claim:
A system comprising: a first thermal sensor sensing a first temperature of the system and generating a first digital signal having a frequency representing the first temperature; a second thermal sensor sensing a second temperature of the system and generating a second digital signal having a frequency representing the second temperature, wherein the second temperature is a reference temperature; a first counter coupled to the first thermal sensor and enabled by the first digital signal, the first counter counts in a first direction in response to a transition of the first digital signal; a second counter coupled to the second thermal sensor and enabled by the second digital signal, the second counter counts in a second direction in response to a transition of the second digital signal; and a digital controller coupled to the first counter and the second counter, wherein the digital controller compares the count values of the first counter and the second counter, wherein if the second counter reaches a target value before the first counter, the digital controller decreases an operating voltage of the system.