Thermal sensor system and method based on current ratio

A thermal sensor system, comprising:

• at least one thermal sensor;
• a voltage control network which applies a reference voltage level and a corresponding delta voltage level to said at least one thermal sensor, wherein said at least one thermal sensor responsively develops a reference current signal and a corresponding delta current signal;
• a current gain network configured to adjust gain of said delta current signal relative to said reference current signal;
• a current compare sensor responsive to said reference current signal and said delta current signal which is configured to provide a comparison metric;
• a controller which is configured to select said reference voltage level and said delta voltage level from among a plurality of reference voltage levels and a corresponding plurality of delta voltage levels, wherein said selected reference and delta voltage levels correspond with a selected one of a plurality of temperature subranges;
• and
• wherein said controller is further configured to control said current gain network to adjust gain of said delta current signal while monitoring said comparison metric to determine a gain differential value indicative of a current ratio of said reference current signal and said delta current signal, and wherein said controller determines a temperature value based on said gain differential value.