Current sensor with input/output isolation

A current sensor formed on a silicon die for measuring a sampled current, the current sensor comprising:

• a first thermal difference generator formed on the silicon die, the first thermal difference generator having a current input portion consisting of a first conductive material;
• the first thermal difference generator including
• a current transfer portion consisting of a second conductive material dissimilar to the first conductive material, the current transfer portion physically coupled to the current input portion and forming a first temperature generating junction therewith;
• a current output portion consisting of the first conductive material, the current output portion physically coupled to the current transfer portion forming a second temperature generating junction therewith, the first temperature generating junction and the second temperature generating junction being spaced apart on the silicon die,
• the sampled current coupled to the current input portion of the first thermal difference generator and the thermal difference generator providing the sampled current as an output from the current output portion, the sampled current flowing through the current input portion, the first junction, the current transfer portion, the second junction, and through the current output portion and generating a first temperature at the first junction and a second temperature at the second junction, wherein the first temperature is less than the second temperature;
• a first thermal difference sensor having a first output portion consisting of a third conductive material and including;
• a current transfer portion consisting of a fourth conductive material dissimilar to the third conductive material, the current transfer portion physically coupled to the first output portion forming a first temperature sensing junction;
• a second output portion consisting of the third conductive material, the second output portion physically coupled to the current transfer portion forming a second temperature sensing junction spaced apart from the first temperature sensing junction;
• the first temperature sensing junction spaced apart from and thermally coupled to the first temperature generating junction, and the second temperature sensing junction spaced apart from and thermally coupled to the second temperature generating junction, the thermal difference sensor providing an output signal on the first and second output portions that is a function of the temperature difference between the first and second temperatures;
• and
• a dielectric barrier interposed between the first temperature generating junction and the first temperature sensing junction and the second temperature generating function and the second temperature sensing junction.